design & marketing of concrete products curriculumcu.clarkson.edu/highschool/k12/pdf/concrete...

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Design & Marketing of Concrete

Products Curriculum [Also taught as PIE – Partners in Engineering Program]

How can we design a concrete product for sale that has

environmentally friendly attributes?

Curriculum Overview....................................................................................................... 2

Sample Teaching Schedule Outline ................................................................................ 3

Concept map Concrete curriculum:................................................................................. 4

Assessment Opportunities .............................................................................................. 5

Summary of NYS MST Standards Covered: ................................................................... 6

Problem Statement.......................................................................................................... 9

Lesson Plans................................................................................................................. 11

Lesson 1 – Introduction to program, solid waste, unit problem ............................................... 11

Lesson 2 – Product Brainstorm � concrete ............................................................................. 20

Lesson 3 – Concrete Research .................................................................................................. 25

Lesson 4 – Waste aggregates and material properties .............................................................. 39

Lesson 5 – Making concrete & safety..................................................................................... 49

Lessons 6 and 7 Foam Bridge Experiment- Forces and Stresses Lab ...................................... 58

Lesson 6&7- Spaghetti Lab- Alternative to Foam Bridge Lesson............................................ 71

Lesson 6 – Forces and Stresses – the shorter (lecture based) lesson for tension and compression .......................................................................................................... 82

Lesson 8 – Testing Cylinders for Compressive Strength......................................................... 91

Lesson 9 – Evaluating results ................................................................................................... 96

Lesson 10 – Weighted Objectives Table and Optimum Mix Sheet.......................................... 99

Lesson 11 – Value of Product................................................................................................. 106

Lesson 12 – Prototype production .......................................................................................... 115

Lesson 13 – Wrap-up / Final assessment................................................................................ 117

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Curriculum Overview

Concrete is one of our most valuable building materials, yet innovations in how concrete can be made, including making and using it in more environmentally friendly ways continues to be developed. Changing the aggregate materials for example is one important change. Concrete products can be made utilizing waste materials as aggregate to provide a valuable use for these materials, reduce their disposal in a landfill, and reduce the need to extract sand and gravel resources from the earth. Concrete products that are porous can also be made to increase water infiltration and reduce runoff. This property is especially important for applications such as parking lots that otherwise create a substantial impervious surface. In one version of the curriculum, eighth-grade technology students address the opportunity for integrating solid waste as aggregate materials in concrete. The curriculum begins with an introduction to solid waste and concrete materials. Students brainstorm about potential waste aggregates that they can integrate into concrete and then make test cylinders out of a wide range of materials. These concrete specimens are tested at Clarkson University facilities provide data on the strength of the concrete mixes that can be used for design choices. Students then make concrete products (e.g., stepping stones) and develop a marketing plan to sell the products based on their environmentally friendly attributes. In the Fall 2008 semester the curriculum is being adapted to consider porous concrete products in alignment of the research of Clarkson’s Dr. Narayanan Neithalath, Assistant Professor of Civil and Environmental Engineering.

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Sample Teaching Schedule Outline

Lesson Plan

Lesson 1: What is solid waste?

Lesson 2: What can we do with solid waste? – Introduce concrete

Lesson 3: Concrete research- WWW/ Packet

Lesson 3: Wrap Up Concrete Research

Lesson 4: Material Properties and Waste Aggregates

Lesson 5: How to make concrete, safety – Mix & pour test cylinders

Lesson 6/7: Forces and Stresses

Lesson 8: Breaking concrete test cylinders (Field trip to Clarkson)

Lesson 9: Go over graphs of cylinder results

Lesson 10: Weighted objectives table / Determine Optimum Mix

Lesson 11: Value of concrete product- marketing

Lesson 11: Wrap Up Marketing

Lesson 12: Prototype Production

Lesson 13: Wrap-up / final assessment – Concrete exam / project rubric/ surveys of fellows

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Concept map Concrete curriculum:

Solid waste -

What it is

Biodegradable

materialsNon-biodegradable

materials persist

Landfills 3 R’s

Products that

can be made from SW Concrete for

non-biodegradable

Compost

PIE

Concrete -

What it is

Concrete as an

industrial material

Waste aggregates

Sources / uses

Types of materials

Safety / handling

Tension/compression

Making concrete

Pouring molded products

Value of the Concrete

Product

Material

Properties

Processing / forming

Concrete test cylinders

Weighted decision

analysis

Solid waste -

What it is

Biodegradable

materialsNon-biodegradable

materials persist

Landfills 3 R’s

Products that

can be made from SW Concrete for

non-biodegradable

Compost

PIE

Concrete -

What it is

Concrete as an

industrial material

Waste aggregates

Sources / uses

Types of materials

Safety / handling

Tension/compression

Making concrete

Pouring molded products

Value of the Concrete

Product

Material

Properties

Processing / forming

Concrete test cylinders

Weighted decision

analysis

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Assessment Opportunities

In-class worksheets and Homework assignments:

• Vocabulary worksheet

• Solid Waste – what can we use? (in class brainstorm worksheet)

• Homework: what we throw away?

• Concrete WEB research – answers to worksheet questions and presentation to class

• Homework: Forces and Stress

• Value of our Product – 2 worksheets available Lab Activities:

• Material Properties or Physical Properties lab/worksheets

• Lesson 6 - (2) lab alternatives: Foam Bridge or Spaghetti lab (forces and stress) data sheet/graphs

• Cylinder Compression test data analysis/graphs

• Weighted Objectives Table Projects:

• Marketing product

• Final concrete product

Unit Exam

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Summary of NYS MST Standards Covered:

Standard 1: Analysis, Inquiry and Design

Engineering Design: 1: Engineering design is and iterative process involving modeling, optimization finding the best solution within given constraints which is used to develop technological solutions to problems within given constraints

• identify needs and opportunities for technical solutions from an investigation of situations of general or social interest

• locate and utilize a range of printed, electronic and human information resources to obtain ideas

• consider constraints and generate several ideas for alternative solutions, using group and individual ideation techniques; defer judgment until a number of ideas are presented; evaluate ideas and explain why the given solution is optimal.

• in a group setting, test solutions against design specifications, present and evaluate results, describe how the solution might have been modified, discuss tradeoffs that might have been made.

Standard 2 – Information Systems

1. Information technology is used to retrieve, process and communicate information and as a tool to enhance learning

• students use a range of equipment and software to integrate several forms of information in order to create good quality audio, video, graphic and text-based presentations

• students use spreadsheets and data base software to collect, process, display and analyze information

• systematically obtain accurate and relevant information pertaining to a particular topic from a range of sources

Standard 3: Mathematics

Measurement: 5: Students use measurement in both metric and English units to provide a major link between abstraction of mathematics and the real world in order to describe and compare objects and data

• Students estimate, make and use measurements in real-world situations

• apply formulas in direct measurement activities

• explore and produce graphic representation of data using calculators/computers

Standard 4 – Science

Physical Setting: 3: Matter is made up of particles whose properties determine the observable characteristics of matter and its reactivity

• observe and describe properties of materials such as density and conductivity

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Standard 5 – Technology

Engineering design: 1: Engineering design is an iterative process involving modeling and optimization to develop technological solutions to problems with given constraints.

• students identify needs and opportunities for technical solutions from an investigation of situations of general or social interest

• locate and utilize a range of printed, electronic and human information sources to obtain ideas

• consider constraints and generate several ideas for alternative solutions

• test their solutions against design specifications

Tools, resources and technological processes: 2. Technological tools, materials and other resources should be selected on the basis of safety, cost, availability…

• choose and use resources for a particular purpose based on analysis and understanding of their properties, cost, availability and environmental impact

• use hand tools and machines to change materials into new forms

Computer technology: 3. Computers as tools for design, modeling, information processing, communication and system control have greatly increased human productivity and knowledge.

• Use a computer to connect to and access needed information from various internet sites.

Impacts of technology: 6. Technology has had positive and negative impacts on individuals, society and the environment and humans have the capability and responsibility to constrain or promote technological development

• students describe how outputs of a technological system can be desired, undesired, expected or unexpected

Standard 6: Interconnectedness: Common themes

Systems thinking

• describe how the output from one part of a system can become input to other parts

Optimization: 6. In order to arrive at the best solution that meets the criteria within constraints, it is often necessary to make tradeoffs.

• determine the criteria and constraints and make tradeoffs to determine the best decision

• use graphs of information for a decision making problem to determine the optimal solution

Standard 7 – Interdisciplinary Problem Solving

Connections: 1. The knowledge and skills of mathematics, science and technology are used together to make informed decisions and solve problems, especially those related to issues of science/technology/society, consumer decision making, design, and inquiry into phenomena.

• students analyze science/technology/society problems and issues at the local level and plan and carry out a remedial course of action

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• students design solutions to a real-world problem of general social interest related to home, school or community using scientific experimentation to inform the solution and applying mathematical concepts and reasoning to develop a solution

Strategies: 2. Solving interdisciplinary problems involves a variety of skills and strategies, including effective work habits; gathering and processing information; generating and analyzing ideas; realizing ideas; making connections and presenting results.

• Students participate in an extended, culminating MST project. The project would require students to: work effectively; gather and process information; generate and analyze ideas; observe common themes; realize ideas and present results.

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Problem Statement

Scenario:

A current problem related to advances in technology and our contemporary lifestyle is how to deal with the enormous amount of solid waste generated by our society. Over the years we have experienced many changes in our lifestyle, mostly making things easier but resulting in the creation of more and more waste. For example, milk – which was at one time sold in refillable glass bottles – is now purchased in disposable paper cartons or plastic jugs. This system is easier, we don’t have to clean the bottles and return them to the dairy, but it adds paper and plastic containers to our solid waste.

The average person in the U.S. disposes of roughly 4.5 pounds of solid waste per day. Most of this waste ends up in landfills, where it is buried in a controlled environment to prevent contamination of the surrounding area. As a result, there are literally mountains of trash now existing on the planet. Our available landfill space is running out.

Environmental engineering is a relatively new technological field, an outgrowth of man’s need to solve problems that have been created by poor decision making and mismanagement related to the impact of technological advances on the environment. They are called upon to find solutions to restore the equilibrium or balance between nature and society. One branch of environmental engineering deals specifically with finding ways to ensure that the disposal of our waste is done in a safe, responsible manner. Problem: Nonbiodegradable wastes

Solutions to the solid waste problem are not limited to the waste disposal end. As products are created and developed, engineers need to bear in mind the waste that these products will eventually generate, and the resulting implications to the environment.

One way to reduce the amounts of waste that are disposed is to avoid creating the waste in the first place. Many materials that we normally throw away may actually be used in the creation of another product. Developing usable products from waste materials is not a new concept, but is becoming more and more important as the amounts and types of solid waste increase.

Your problem assignment is to find a way to reuse solid waste in the generation of a new product. Your specific tasks include:

1. Investigate materials in the solid waste that may be adaptable as durable, raw materials for another product.

2. Explore the creation of different types of products using waste materials.

3. Determine the waste material most suitable for use in your product.

4. Design and create a prototype of your product.

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5. Test the prototype for acceptability, make improvements as necessary.

6. Manufacture your product and use it in a way that benefits your school or community.

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Lesson Plans

Lesson 1 – Introduction to program, solid waste, unit problem

1. Background Narrative:

Through the eras of humankind’s development, humans have created ways to make their existence easier. Native cultures had a profound respect and appreciation for the living environment. For example, they hunted only what they needed to survive and used all parts of their prey to meet their food, clothing and shelter needs. Modern man, having had the advantage of great technological advances throughout the 20th century, has not demonstrated the same level of appreciation for the environment at all times. While advances in technology have improved modern man’s existence certain decisions relative to his environment became a lesser priority than the goods and products manufactured to sustain his lifestyle. The result or impact has been the creation of stress on the fragile equilibrium of the natural environment.

Environmental engineering is a relatively new technological field, an outgrowth of man’s need to solve problems that have been created by poor decision making and mismanagement related to the impact of technological advances on the environment. Environmental engineers are called upon to find solutions to restore the equilibrium or balance between nature and society. But environmental engineers cannot solve all of the environmental problems caused by advancing technology - all engineers should consider environmental impacts associated with the products, processes and services they design and offer.

One current problem related to advances in technology and our contemporary lifestyle is how to deal with the enormous amount of solid waste generated by our society.

Some solid waste statistics –

(4.5 lbs trash/person/day is generated in USA – a bag of trash that contains 4.5 lb. would be a good illustrative example)

breakdown for the municipal fraction of solid waste (2001): paper and paperboard 38% yard and food waste 23% Plastics 11% Metals 8% Glass 6% Other 14%

Note that much of this high rate of trash generation is associated with the choices we make in our lives and our modern society, usually with the goal of added convenience or comfort. For example – we now use disposal milk jugs rather than reusable, refillable glass bottles that have to be cleaned before they are collected or returned for reuse.

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2. Performance objectives

• Students will be able to explain what solid waste is.

• Students will demonstrate an understanding that advances in society and technology have contributed to the solid waste problem.

• Students will be able to list problems with current solid waste disposal methods.

• Students will be able to define the terms reduce, reuse and recycle.

Standards:

• NYS: 4.7, 5.5, 5.6, 7.2

• US Sci: 5.3, 5.4, 5.6

• US Tech: 2.1, 2.2, 2.3. 3.2, 4.1

3. Resources

• Background on solid waste: see EPA solid waste web site: http://www.epa.gov/msw/

• Vocabulary worksheet

• Silverstein, S., Where the Sidewalk Ends, Harper Collins Publishers, New York, 1974. ISBN 06-025667-2

• Bill Nye Science Guy “Garbage”1

OR Beth Pike video entitled “Garbage into Gold” 2

• Technology Problem Solving Method Overhead

• Problem statement (make overhead or display in classroom)

• Worksheet: Solid Waste – what can we use?

• Homework assignment: What we throw away

4. Instructions

This is the first day – make it fun and exciting!!

1. (Less than 5 mins) Take a few minutes to introduce yourselves, if you are new in the classroom! Who are you? What do you study at college? Why do you study engineering? Does anyone know what an engineer does?... Engineers solve problems! Engineers use science and math to make improvements to the human environment and way of life. Inform the students that over the next few weeks you’ll be working with them to solve an engineering problem.

2. (3-5 mins) “This is our problem!” point to the bags of trash. Can anyone guess what our problem is? The US produces more than 245 million tons of solid

1 Order at http://dep.disney.go.com/educational/store/detail?fromsearch=1&product_id=77A53VL00 2 Order at http://www.videoproject.com/gar-063-v.html

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waste per year. That is equivalent to 4.5 lbs of trash per person per day. Have one student come up and lift a 4.5 lb bag of trash. Show pie chart with percentage breakdown of solid wastes.

***Also in here as another option: Read the Shell Silverstein’s Where the Sidewalk Ends “Sarah Cynthia Sylvia Stout Would Not Take The Garbage Out.” – or, show short clips from Bill Nye video “Garbage” or “Garbage into Gold”

3. (10 mins) Activity: have students come up and quickly organize trash into groups shown on pie chart. Percentages should match what is on pie chart to give visual representation of solid waste breakdown.

4. Pass out fill in the blank vocabulary worksheet. Have students work on the worksheet during the Bill Nye video.

5. (20 mins) Start Bill Nye video.

6. (10 mins) Go over vocabulary worksheet. Ask for examples- give me an example of a biodegradable material, etc.

7. (5 mins) Introduce the problem that we will be solving over the next 3 weeks: “We want to reduce the amount of non-biodegradable solid waste that the

community disposes by turning it into something valuable that the community can use.” (ask: why would we want to do that? So it will not accumulate and cause problems as in poem!)

8. (15 mins) Short lesson on problem solving: How will we solve this problem – does anyone have a good approach to solving a problem? Ask how many of them consider themselves to be “good” problem solvers. o Introduce the technology problem solving method (show poster).

o Ask students if they have seen this before! Identify the steps on board with them, to reinforce. Emphasize that this is an iterative process.

o Give an example of using the problem solving method, applying it to a very simple problem: what will I wear today? Field responses to each step and write on board.

� Define problem (what to wear)

� Describe the results you want (to be dressed appropriately, look good, be warm enough, etc.)

� Gather information (What’s the weather? What’s clean? What still fits? What do I feel like?)

� Think of solutions (pull out a few outfits)

� Choose best solution (best choice from the available options)

� Implement solution (get dressed!)

� Evaluate results, make changes (look in mirror, go outside, etc…)

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9. (5 mins) Define where we are on the problem solving method – Describing the problem, describing the results we want. Next step – gather information, think of solutions. Then we will choose a solution, implement it, and evaluate whether or not it works. (This is engineering!)

10. (2 min) Closure – reiterate the problem statement. If you watched the movie, ask what valuable products were shown in the video (oil from tires, soil from compost). Ask students if they think we can make oil from tires in tech class. If you didn’t watch the video, ask students what types of products they think might be made from some of the materials they found in the trash (e.g., fleece from recycled plastic). Indicate that in tomorrow’s class – we will brainstorm and decide what valuable product we can make from solid waste so that less is going to the landfill.

11. Collect student vocabulary sheets or have them saved in a binder for later use. Tell students that they will be graded on all the material you cover, so they need to save their work!

12. Distribute homework assignment and go over it. Students will be asked to record, for the next 3 days, the solid waste that they generate, and consider whether items are biodegradable or non-biodegradable and if they can be reused or recycled.

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1

7

6

54

3

2

Describe the problem

Describe the results you want

Gatherinformation

Think of solutions

Chose the bestsolution

Implement thesolution

Evaluate results and make necessary changes

Reenter the design spiral at

any step to revise as necessary

Solving a problem is faster, easier and has better results if you follow a procedure. But we must also remember that problem solving may require you to go back and forth between these steps, they are not always followed in order.

The procedure below shows the seven steps of the problem solving spiral. We will use these as we solve our problem.

The Technological Method of Problem Solving

1

7

6

54

3

2

Describe the problem

Describe the results you want

Gatherinformation

Think of solutions

Chose the bestsolution

Implement thesolution

Evaluate results and make necessary changes

Reenter the design spiral at

any step to revise as necessary

Solving a problem is faster, easier and has better results if you follow a procedure. But we must also remember that problem solving may require you to go back and forth between these steps, they are not always followed in order.

The procedure below shows the seven steps of the problem solving spiral. We will use these as we solve our problem.

The Technological Method of Problem Solving

Adapted from Hacker, M, Barden B., Living with Technology, 2

nd edition. Delmar Publishers,

Albany NY, 1993.

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Solid Waste – Vocabulary Sheet

Name: ______________________

Solid Waste - ____________________________________________________________________________________________________________

Biodegradable – __________________________________________________________________________________________________________________________________________________________________

Non-biodegradable – __________________________________________________________________________________________________________________________________________________________________

Landfill – __________________________________________________________________________________________________________________________________________________________________

Reduce – __________________________________________________________________________________________________________________________________________________________________

Reuse – __________________________________________________________________________________________________________________________________________________________________

Recycle – ________________________________________________________________________ ____________________________________

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Solid Waste – Vocabulary Sheet

Name: _key_____________________

Solid Waste - __

any discarded material that would not normally go down the drain.

Biodegradable – __materials that were once living tissues (biotic). These wastes can be broken down by other living organisms into simple substances.

Non-biodegradable – Composed of materials that were never living tissues (abiotic). For example, mineral ores. Living organisms cannot break down these wastes into simple substances.

Landfill – _A system of trash and garbage disposal in which the waste is buried according to a formal disposal plan, within a special site designed by humans to contain the wastes.

Reduce – _to diminish in size, amount, extent, or number the amount of materials that are discarded.

Reuse – __to use materials again for the same intended purpose, especiallyl after reclaiming or reprocessing.

Recycle – To process waste materials through a series of changes or treatments in order to regain material for human use.

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Name:_____________________________________ Date:_____________

Homework Assignment: What we throw away.

For the next three days, record the solid waste that you generate and complete the table

Check one

solid waste item bio-

degradable

non-bio-

degradable

Can it be Recycled or

Reused?

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Solid Waste – What Can We Use?

What are some types of things that you might find in solid waste?

_______________________________________________________________________________________________________________________________________

_______________________________________________________________________________________________________________________________________

Which can we use to solve our

problem?

Which cannot be used to solve

our problem?

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

___________________________

Vocabulary:

Biodegradable:___________________________________________________________________________________________________________________________________________________________________________________________________________________________

Non–Biodegradable:________________________________________

__________________________________________________________

__________________________________________________________

Which types of solid waste materials can we use to solve our problem?

____________________________________________________

Lesson 2 – Product Brainstorm � concrete

1. Background Narrative

A growing awareness and recognition of the negative impacts of such solid waste disposal practices as incineration and landfill has led to the investigation of alternative, environmentally friendly, methods. Such focused exploration by scientists and engineers has led to the implementation of what are now referred to as the 3 R’s of solid waste management:

� Reduce

� Reuse

� Recycle

Reduce refers to the practice of minimizing materials that could potentially become solid waste. Wherever possible, less is better. For example, can two Styrofoam boards provide the same protection in shipping a product as four?

The second component to the 3R’s is Reuse, the implementation of an item with the intent of utilizing its original form and function. For example, returnable bottles are not only a less expensive method of purchasing some beverages but a more environmentally friendly way as well.

Recycling calls for the destruction of elements in their original form for the purpose of re-utilizing them in the manufacturing of other products. Glass bottles when pulverized and treated can be re-shaped for use in other glass products.

Widespread acceptance and practice of the three R’s can help to reduce problems associated with solid waste disposal, simply by reducing the amounts of waste that ultimately must be disposed of. However, future projections of effectiveness, in the face of a growing human population and greater technological advances, is in question. Humankind’s ability to be resourceful and innovative in the solution of this challenge will be severely tested. The role of engineers from all disciplines, as well as the role of the individual consumer, will be critical in this process. Every person who generates waste must start critically thinking about his or her waste production, implementing ways to reduce the amount of waste they produce or finding ways to reuse or recycle that waste.

Concrete represents a valuable building material that may offer a repository for utilizing certain categories of solid waste materials. Through an understanding of what concrete is and how it is made, students will be able to select suitable waste materials as aggregates.

We now need to repeat our problem solving process with a new problem – Make a concrete product utilizing waste materials. As a part of the overall problem solving method, we need to use engineering design principles to choose our materials and product, and to plan the process for constructing or making our prototype. The collection of experimental data to support our decisions will be required, as will a logical approach to pick suitable aggregates based on multiple technical, social and aesthetic criteria. The approach used by the students throughout this process reflects the approach used by practicing engineers.

Students need to perform research to gather answers to questions they have about their problem solution. Ways to do research include: do an experiment, look up information in

the literature (library or WWW), or ask an expert. Through an understanding of what concrete is and how it is made, students will be able to select suitable waste materials as aggregates. The World Wide Web helps to provide the understanding that we need to implement this solution.

Students will share the information they have gathered on their group’s concrete topic with the entire class. By the end of the lesson students should have a good grasp on the information covered in each concrete research topic. This will give students a very good basic understanding about how concrete is made and tested, how it is affected by weathering, and some of its physical properties.

Some key facts about concrete that are pertinent to this lesson include:

• Concrete is a mixture that becomes hard following a chemical reaction.

• There are 5 types of Portland cement (Types I-V). The properties of finished concrete will depend on which type of cement is used.

• The ratio of water to cement in most concrete mixtures is about 0.5:1 by weight. For example, if you used 2 pounds of cement in your concrete you would need to add 1 pound of water to your mixture.

• In most concrete mixtures sand is used as a fine aggregate and pea stone is used as a course aggregate.

• During the curing process concrete gains most of its strength. Concrete hardens due to hydration. Hydration only occurs if there is enough water to react with the cement. For this reason concrete needs to be kept wet during curing, by frequent watering and covering with wet cloth or plastic to hold in moisture.

• Concrete is usually tested after 7 or 28 days of curing. Testing at 7 days will provide a good basis to compare different mixtures (provided that all mixtures have cured for the 7 days), but by the 28th day the concrete has gained most of its strength. Concrete’s strength is most commonly tested by applying compressive force to a sample until it fails. The compressive strength is measured in PSI.

Air entrainer is a material added in very small amounts to the concrete mix, to help trap air into the finished product. When concrete which is air entrained has cured, it has millions of tiny air bubbles. These air bubbles give water a place to expand when it freezes. Without these bubbles the concrete would crack much more easily after many freeze/thaw periods. Concrete types that end in an “A,” are air entrained. For example Types IA, IIA, and IIIA are air entrained but Types I, II, and III are not.


• Students will be able to recognize different materials that are currently made from solid waste.

• Students will be able to recognize concrete production as a useful way to reuse solid waste materials.

• Students will be able to explain where the new problem (How do we make concrete?) fits into the entire curriculum and the larger problem.

• Students will be able to list different research methods.

• Students will be able to discriminate, from a large amount of gathered data, which pieces of information are relevant or important to solving our problem.

• Students will be able to answer questions about several concrete topics, using the knowledge gained from group discussion.

Standards:

• NYS 2.1, 2.2, 5.3, 5.5

• US Sci: 2.3

• US Tech: 1.3, 3.2, 4.1, 5.4

3. Resources

• Examples of recycled, reused materials (e.g., polartec fleece, plastic lumber, glass bottles, plastic containers, cardboard or paperboard, concrete)

• Research Worksheets (in Lesson 3)

• Access to the internet, or if unavailable, information packets for the students containing printed resources

• Teacher’s copy of internet resources / web sites

• PowerPoint files (for teacher):

1. Concrete Basics

2. Aggregate Properties

4. Instruction plan

1. (5 min) Introduction

a. Remind students of our problem statement “We want to reduce the amount of non-biodegradable solid waste that the community disposes by turning it into something valuable that the community can use.” Show problem solving spiral transparency -Today we are going to brainstorm to generate ideas, choose a potential solution and then learn more about that particular solution – reenter the spiral then to make additional choices.

b. Discuss what would make a product “useful.”

c. What non-biodegradable wastes do you think we could use? (write suggestions on board – recall list of materials found in trash)

i. possibilities include – rubber, tires, plastic, glass, metal

2. (10 min) Discuss the idea of making usable products from solid waste materials. “The 3 Rs – reduce, reuse, recycle – suggest that many useful products can be made from non-biodegradable waste materials.

a. Provide various materials for demonstration and discussion, which are examples of solid waste being Reduced, Reused and Recycled (good examples – for “reduced” category, bring in some packaging types that show how waste is

reduced when you use less packaging, for example, or even using the back sides of paper reduces the amount of paper used. For reused and recycled – glass bottles, fleece jacket, concrete stepping stone, “plastic” lumber, recycled paper, both purchased and handmade.) Hold samples up or pass around the class, have students guess what they think the original waste materials were that went into making the product.

b. What is the difference between reuse and recycle?

Reuse – to use materials again for the same intended purpose, especially after

reclaiming or reprocessing. Recycle – To process waste materials through a series of changes or

treatments in order to regain material for human use. (have students write on their vocabulary sheets)

c. We are mainly interested in ways to reuse (that’s specified by our problem statement). Engage students in identifying additional examples of items that are reused or recycled. (new things are coming along all the time!) Point out to the students that although most human waste goes into the landfill, some people are actually using waste materials to make new products, or are reusing materials over and over again, keeping them out of the landfill. Also, as new materials are developed, people (engineers!) are working on new ways to make products from their waste materials. A good example is polar fleece, a relatively new material made from waste plastics.

Important point – we can only recycle our waste because there is a “market” for the waste. Companies want to buy our waste paper, metal, plastic, etc., because they are going to make products with them or use them as some kind of input to what they do. Engineers are the ones who come up with the ideas of ways to

reuse these waste products.

d. Brainstorm with the students about additional things that they, themselves, could make using different waste materials, to solve our problem. Lead toward building materials -- what kinds of building materials are there? What kinds of building materials can we make out of recycled materials? What kinds of building materials can we make in this classroom? Concrete… Write the term “concrete” on the board.

3. (5 min) generate discussion about concrete. OK – so now we’ve got a new problem to investigate – concrete!

a. What do we know about concrete? Who has made concrete? How did you make it? What did you put in it? What have you made out of concrete? Where do you see concrete everyday? When you look closely at concrete what do you see in it?

b. What don’t we know, or what do we need to find out about concrete? Do we know what is in concrete? How much of each ingredient do we put in? How do we make concrete strong enough to make a bench (planter)? Have you seen sidewalks crack? How do we keep our product from cracking?

4. (5 min) Introduce need for research

a. How are we going to find out the answers to all these questions? Where can you go to look up answers to these questions? The library and WWW are both good sources for information on concrete. We will be going into the computer lab (or using notebooks of materials) to research answers to our questions, and some additional questions that we think are important for you to answer.

b. Introduce World Wide Web and its advantages and disadvantages

− There are many advantages to the World Wide Web. For example, it is seemingly endless in the amount of information it contains. Sometimes information can be obtained faster than by other methods.

− For almost every advantage of the World Wide Web there are disadvantages. For example, even though there is a large amount of knowledge it is often hard to find. Unlike a library, it is poorly organized; there is no card catalog to go to. It is difficult to tell how reliable a source is on the Web because anyone can make a web page, and put almost anything they want on it.

5. (5 min) Concrete research Assignment

a. Handout research worksheets and assign students into groups. Students may be asked to find as much information as possible, or assign one of the 5 categories of questions to each group (if you only have 2 days for this assignment, assign each group to find answers to one category, and if they finish let them continue with other questions).

b. Inform students that they will be presenting their answers to the rest of the class (particularly good if you have each group do one set of questions). Provide overheads for them to write their answers on for the presentation.

c. Read through the directions on the worksheets with the students. Ask students if they understand the directions.

d. Let students begin the computer work, if there is time, and assign the rest of the web research as homework – students are to try and find internet access outside of the classroom, and to complete as much of the assignment as possible.

e. Remind students that they will share their answers the following day with the rest of the class.

6. Wrap up: Conclude lesson by reminding students:

a. We brainstormed and identified a solution to our problem – add waste products to concrete. Next – we have to learn more about this solution to make additional decisions about our solution.

b. We will go over the entire worksheet next lesson to fill in the questions that the other groups worked on. Encourage students to learn more about concrete at home on the WWW or in the library in their free time.

Lesson 3 – Concrete Research


Students will research concrete topics on the internet, and then share the information they have gathered on their group’s concrete topic with the entire class. By the end of the lesson students should have a good grasp of the information covered in each concrete research topic. This will give students a very good basic understanding about how concrete is made, tested, and some of its physical properties.

This information sharing can be done quickly by having students just read their answers while other students fill in their blanks, or if an assessment is desired, groups could prepare overheads of the answers to their sections and get up in front of the class to share their information. If this is done, students should get a copy of the grading rubric that will be used so they know what is required.

Major Concepts:

• Concrete – A heterogeneous mixture of cement, water, and aggregate.

1. Cement – The “glue” that holds the concrete together.

2. Fine Aggregate - Generally consist of natural sand or crushed stone with most particles ranging in size from 0.025 to 6.5 mm.

3. Course Aggregate - Any particles greater than 4.75 mm, but generally range between from 6.5 to 38 mm in diameter.

4. Water – Reacts with the cement to start the hardening process of the mixture.

• Hydration – The hardening of concrete through a chemical reaction of cement with water.

• Curing – The period of time that the concrete is left to harden.

• Compressive strength - Is tested by pouring cylinders of fresh concrete and measuring the force needed to break the concrete cylinders at proscribed intervals as they harden.

• Pounds Per Square Inch (PSI) – The unit used to measure the compressive strength of concrete.


• Students will be able to determine what information is relevant to understand, from the gathered information, in order to solve our problem.

• Students will be able to answer questions about each concrete topic, using the knowledge gained from group discussion.

Standards:

• NYS 2.1, 2.2, 5.3, 5.5

• US Sci: 2.3

• US Tech: 1.3, 3.2, 4.1, 5.4

3. Resources

• Key Concept Worksheet

• Student Research Worksheets, along with the answer key

• Blank overheads

4. Instruction plan

1. (5 min) Introduction: Since maximizing discussion time is important for this lesson the introduction should be kept short. Simply recap what you told the students last lesson about what they are to do today. Explain that we will go through the work sheet in its entirety and the group that researched a given topic will be responsible for explaining the answers to those questions to the class (either just saying the answers or – preferably – standing in front and presenting the answers on an overhead), while the rest of the class writes down the answers on their own work sheet packets. Also explain that students will be given a grade based on student participation in class discussion, and correctness and completeness of group answers. (provide rubric if used) Remind students that they will be tested on this material at the end of the

unit, so they need to record the answers!

2. (15-20 min) Computer time: Allow the students approximately 15 minutes on the computers to finish up any loose ends, and to give those students who could not obtain Internet access outside of the classroom a chance to participate. Students who finished the questions in their section are encouraged to “surf the web” to find information on other sites.

3. (10 - 15 min) Following this work period, instructors should facilitate discussion by asking the questions on the research worksheet and writing the correct answers on the blackboard or overhead (having students come up to write their answers on the overhead, or letting each group make a short presentation with their information, takes longer but is a good way to keep them engaged if it’s possible to do). Throughout discussion – keep students focused on relevant material. As each question is addressed, ask a different member of the designated group to provide an answer – this way every student is required to provide and answer for the benefit of the class – if there are more students than questions in a group, ask for alternate responses and compromise on the answer.

4. Hand out key concept worksheet: If time permits go over the key concepts worksheet with the students and ask if there are any questions about it. Tell students to save these! Inform them that there will be a test at the end of this unit over this material!

5. Wrap up: Review what the students learned –

a. they now know about the ingredients in concrete (cement, water, sand and gravel – cement and water critical for making “concrete,” sand and gravel really just fillers to reduce the cost - cheaper than cement).

b. They’ve used the web as an information resource – was it effective? Was it quick?

c. Tomorrow – learn more about aggregates and how we can use waste materials for aggregate.

Name _____________________________ Date ______________________

Clarkson Partnership

Key Concepts:

• The ratio of water to cement in most concrete mixtures is about 0.5:1 by weight. For example, if you used 2 pounds of cement in your concrete you would need to add 1 pound of water to your mixture.

• In most concrete mixtures sand is used as a fine aggregate and pea stone is used as a course aggregate.

• During the curing process concrete gains most of its strength. Concrete hardens due to hydration. Hydration only occurs if there is enough water to react with the cement. For this reason concrete needs to be kept wet during curing, by frequent watering and covering with wet cloth or plastic to hold in moisture.

• Concrete is usually tested after 7 or 28 days of curing. By the 28th day the concrete has gained most of its strength. Concrete’s strength is most commonly tested by compression, and measured in PSI.

Concrete Research Key Concepts

Concrete Vocabulary:

• Concrete – A heterogeneous mixture of cement, water, and aggregate.

1. Cement – The “glue” that holds the concrete together.

2. Fine Aggregate - Generally consist of natural sand or crushed stone

with most particles ranging in size from 0.025 to 6.5 mm.

3. Course Aggregate - Any particles greater than 4.75 mm, but generally

range between from 6.5 to 38 mm in diameter.

4. Water – Reacts with the cement to start the hardening process of

the mixture.

• Hydration – The hardening of concrete through a chemical reaction of

cement with water.

• Curing – The chemical process required for the hydration of cement. This

process takes a period of time, which is referred to as “curing”.

• Compressive strength - Is tested by pouring cylinders of fresh concrete and

measuring the force needed to break the concrete cylinders by applying

compression at proscribed intervals as they harden.

• Pounds Per Square Inch (PSI) – The unit used to measure the compressive

strength of concrete.

Concrete Web Research

Look through this website to help you answer the questions below: [We created a webpage that has all the web links to the concrete sites - to eliminate the need for students needing to type the url addresses – saves lots of time!]

If your group finishes your section try the extra credit or find the answers to

some of the other questions. Also feel free to help other groups out that are

having trouble finding answers to their questions.

Group 1. Cement and Concrete

1. What is the difference between concrete and cement?

2. What is the name of the chemical reaction that takes place in concrete?

3. What are the two ingredients that take part in this reaction?

4. There is more than one type of cement, list the name and type of the most

common form used for general purposes.

Group 2. Concrete Mixture

5. What four ingredients do you mix together to make concrete?

6. Approximately what percentage of concrete’s volume is made up of coarse

aggregates, fine aggregates, and cement?

7. What is the best water-to-cement ratio to use to make strong concrete?

8. Explain the “Rule of 6’s” for mixing concrete:

Group 3. Aggregates

9. What are the approximate sizes of coarse and fine aggregates (in mm)?

10. Give an example of each type of aggregate:

11. What happens to concrete if the aggregates are not clean?

12. What percentage of the concrete’s volume is taken up by the aggregates?

Group 4: Curing

13. What is curing?

14. What temperature range is ideal for curing?

15. What chemical reaction happens during curing?

16. Will concrete cure underwater? Why or why not?

Group 5: Testing 17. What is 28-day strength?

18. How long does it take for concrete to reach its greatest strength?

19. What unit of measure is used to describe concrete’s strength?

20. What would be a good strength for concrete?

21. What test do we usually perform to test concrete’s strength?

Extra Credit

22. Search for “recycled waste materials in concrete.” Can you name 2 waste

materials that people have used to make concrete?

23. Describe 2 benefits of using waste materials instead of sand and gravel in

concrete.

Concrete Web Research

List of Websites (2004): http://www.cement.org/basics/ http://www.ecosmart.ca/facts/what.asp http://www.wrmca.com/ http://dept.physics.upenn.edu/courses/gladney/mathphys/subsubsection1_1_3_1.html http://va.essortment.com/mixingconcrete_rupc.htm http://doityourself.com/concrete/cement_water_ratio.htm http://www.clovisusd.k12.ca.us/rec/classofmatter.htm

For the instructor:

Note: before doing this activity, check the websites to see that they are still current!

Categories – Topics covered: Cement- types (I-V), difference from concrete, reaction with water (hydration) http://www.ecosmart.ca/facts/what.asp Aggregate- Fine, course http://www.cement.org/basics/concretebasics_aggregate.asp Curing- how, length of time, temperature, under water? http://www.cement.org/basics/concretebasics_curing.asp http://www.cement.org/basics/concretebasics_faqs.asp Mix – What recipe, Method of 6, 1:3:4, homogeneous mixture http://va.essortment.com/mixingconcrete_rupc.htm http://www.cement.org/basics/concretebasics_concretebasics.asp http://www.cement.org/basics/ http://doityourself.com/concrete/cement_water_ratio.htm http://dept.physics.upenn.edu/courses/gladney/mathphys/subsubsection1_1_3_1.html http://www.clovisusd.k12.ca.us/rec/classofmatter.htm Testing – Compression, Normal PSI strength http://www.cement.org/basics/ Weathering- Hot & Cold, deicers, Air Entrained http://www.wrmca.com/ Note: If you need to make some groups larger than others, make groups 1 and 2 larger, there is more information in their topics.

Concrete Web Research KEY

Group 1. Cement and Concrete

1. What is the difference between concrete and cement?

“Cement is the glue that holds concrete together.” Although the terms cement and concrete often are used interchangeably, cement is actually an ingredient

of concrete. Concrete is basically a mixture of aggregates and paste. The

aggregates are sand and gravel or crushed stone; the paste is water and

portland cement.

2. What is the name of the chemical reaction that takes place in concrete?

Hydration is the chemical reaction that occurs in concrete.

3. What are the two ingredients that take part in this reaction?

a. Cement b. Water

4. There is more than one type of cement, list the name and type of the most

common form used for general purposes.

Type I is a general purpose portland cement suitable for most uses

Group 2. Concrete Mixture 5. What four ingredients do you mix together to make concrete?

Cement

Coarse aggregate

Fine aggregate

Water

6. Approximately what percentage of concrete’s volume is made up of coarse

aggregates, fine aggregates, and cement?

11% Cement 41% Coarse Aggregates 26% Fine Aggregates

7. What is the best water-to-cement ratio to use to make strong concrete?

About 0.5:1 by weight

8. Explain the “Rule of 6’s” for mixing concrete:

• A minimum cement content of 6 bags per cubic yard of concrete,

• A maximum water content of 6 gallons per bag of cement,

• A curing period (keeping concrete moist) a minimum of 6 days, and

• An air content of 6 percent (if concrete will be subject to freezing

and thawing).

3. Aggregates 9. What are the approximate sizes of coarse and fine aggregates (in mm)?

• Coarse (4.75 mm, but generally range between from 6.5 to 38 mm in diameter)

• Fine (most particles ranging in size from 0.025 to 6.5 mm)

10. Give an example of each type of aggregate:

• Coarse: Pea Stone, crushed rock, gravel • Fine: Sand

11. What happens to concrete if the aggregates are not clean?

For a good concrete mix, aggregates need to be clean, hard, strong particles free of absorbed chemicals or coatings of clay and other fine materials that could cause the deterioration of concrete.

12. What percentage of the concrete’s volume is taken up by the aggregates?

Aggregates account for 60 to 75 percent of the total volume of concrete.

4: Curing 13. What is curing?

Curing is the period of time that the concrete is left to harden.

14. What temperature range is ideal for curing?

After concrete is placed, a satisfactory moisture content and temperature (between 50°F and 75°F) must be maintained.

15. What chemical reaction happens during curing?

Hydration is the chemical reaction that occurs during curing.

16. Will concrete cure underwater? Why or why not?

Yes, concrete will cure underwater. Portland cement is a hydraulic cement which means that it sets and hardens due to a chemical reaction with water. Consequently, it will harden under water.

5: Testing 17. What is 28-day strength?

The time period of 28 days was selected by specification writing authorities as the age that all concrete should be tested. At this age, a substantial percentage of the hydration has taken place.

18. What unit of measure is used to describe concrete’s strength?

Concrete’s strength is measured in pounds per square inch (PSI).

19. How long does it take for concrete to reach its greatest strength?

Concrete will reach its ultimate strength after several years.

20. What would be a good strength for concrete?

3,000 – 4,000 PSI is a good strength for concrete.

21. What test do we usually perform to test concrete’s strength?

Compressive tests are typically preformed to test concrete’s strength.

Grading Rubric: Internet Research Activity and Presentation

Outcome Distinguished Proficient Apprentice Novice

Category 4 Points 3 Points 2 Points 1 Point

Content

Thoroughly and clearly states the main points and precise details that are accurately

focused on the internet research activity.

Adequately states the main points and details that are accurately focused on the internet research activity.

States most of the main points and details that focus on the

internet research activity. May include some unnecessary

information.

States few main points and details that focus on the internet research activity, or information

does not relate to topic.

Organization

Clearly organized into a logical sequence. Excellent use of a

flowchart. Excellent introduction and conclusion.

Adequate evidence of a logical sequence of information. Good use of a flowchart. Satisfactory

introduction and conclusion.

Fair evidence of a logical sequence of information. Some

use of a flowchart. Weak introduction and Conclusion.

Minimal or no logical flowchart usage. No logical organization;

some digressions. Unclear, confusing, no introduction or

conclusion.

Delivery

Effectively and creatively delivers the information while

staying on topic and considering the audience. Uses voices and variations; interesting and vivid

to hear.

Adequately delivers the information while staying on

topic and considering the audience. Speaks clearly and

confidently.

Delivers the information but does not stay on topic. Little

consideration of the audience. Uses incomplete sentences.

Little or no attempt is made to stay on the topic. Does not

consider audience. Difficult to understand.

Preparation Presentation shows detailed preparation and practice in

delivery.

Presentation shows satisfactory preparation as well as practice

in delivery.

Presentation shows some preparation as well as some

practice in delivery.

Presentation is lacking in preparation and in practice of

the delivery.

Written Worksheet Questions

Answers the questions clearly and completely. Provides all key

information.

Adequately answers the questions. Some information

may be missing.

Answers the questions somewhat. Most information

missing, and little or no use of vocabulary, or improper use.

Does not answer the questions correctly.

Neatness Clear, creative, and concise. Adequate. Needs interpretation from

student. Not Legible.

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Lesson 4 – Waste aggregates and material properties

1. Background Narrative:

Materials have a wide range of properties that affect how we use them in engineering processes. Materials are often chosen based upon their properties. Properties of a material include strength, hardness, density, appearance, ability to conduct electricity, and resistance to corrosion.

Some major types of material properties include mechanical, optical, thermal, electrical and magnetic properties.

Material properties that are important for determining if a material is suitable for use as an aggregate include:

• Unit weight (bulk density, or how densely the aggregate packs – how much void space there is)

• Specific gravity (material density)

• Particle shape and surface texture (want rough surface with edges, so material will hold together, as opposed to smooth, round surface)

• Shrinkage (will the material shrink as it ages?)

• Absorption, surface moisture (want particles that do not absorb much liquid)

• Resistance to freezing/thawing (obviously we want materials that are resistant)

It is important for students to understand all of these properties so they can make informed decisions about which materials work best for different applications. In this activity, we will examine the properties of a wide range of materials that could be used as aggregates in concrete. Students will learn about making concrete using different waste materials for coarse and fine aggregates. The benefits and burdens of using waste aggregates will be emphasized in this plan. Then the lesson will continue by going over material properties so appropriate choices can be made for the concrete project.

Note that for many of our 8th grade students, only a brief overview of material properties is needed. Students need to understand some of the more basic properties and understand the concept that in order to effectively use a material, you need to take into account the properties it has (e.g., need a good electrical conductor if you want to make wire, a good insulator if you want to insulate a house or make a potholder).

Major concepts

1. Define coarse aggregate as larger aggregate in mix.

2. Define fine aggregate as sand sized aggregate in mix.

3. Coarse aggregates that can be used, examples… a. Stone b. Shredded rubber tire c. PVC d. Wood Chips e. Glass f. Paper g. Gypsum h. Anything else, be creative and cautious!

4. Fine aggregates that can be used, examples…

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a. Sand b. White glass (used for pottery) c. Green glass d. Used sand e. Recycled plastic (shredded in manufacturing process – looks like coconut) f. Anything else, be creative but cautious! We went to local manufacturing businesses and

found white glass and green glass (that is, fine white power and tiny glass beads) as well as a waste product from the manufacture of plastic parts – long strings of paper-thin 3/8” wide PVC – looks kind of like old movie reels!

5. Material properties - Vocabulary /Terms: Brittle Conductor Ductile Elastic Ferrous Non-ferrous Insulator Plasticity Thermal Toughness Unit weight/bulk density Specific gravity Void space Particle shape Surface texture Shrinkage Absorption Resistance to Freezing/thawing


• Students will be able to identify needs and opportunities for technical solutions from an investigation of situations of social interest.

• Students will be able to formulate ideas on how to incorporate waste in the production of a valuable construction product such as concrete.

• Given a list of material properties, students will be able to explain what those properties mean and give an example of what type of materials might have each property.

• Students will determine which types of properties are exhibited by materials suitable for use as concrete aggregates.

• Based on their material properties, students will be able to define specific waste materials that could be used as aggregates in concrete.

Standards:

• NYS 4.3, 4.7, 5.2

• US Sci 2.2

• US Tech 1.3, 2.2

3. Resources

• Bring in samples of all Coarse and Fine aggregates listed above (plus others as appropriate)

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• Samples of waste materials for Material Properties Worksheet – use materials that students can handle, stretch, tap, feel, etc. for example:

1. shredded rubber, and some rubber bands

2. shredded plastic samples, and plastic milk jugs or bottles (note number on bottom of sample, match object to correct sample of shredded plastic!)

3. shredded PVC and a piece of PVC pipe

4. ground glass and glass bottles

5. shredded newspaper and several pieces of newspaper, whole

6. ashes from a wood stove – no real large sample available, provide an open container and spoon so students can test density and examine with magnifying glass

7. wood chips or saw dust, and a block of wood

8. shredded aluminum or metal, and a few waste metal containers (tin cans)

9. aluminum foil – shredded and whole

• Beaker of water (to test density and surface absorption)

• Magnifying glass (to examine surface texture and shape)

• Teacher resources: Information about concrete

• PowerPoint – see “Teacher resource – concrete used a construction material with pictures” and “Teacher resource – Overview of Aggregate Properties”

• Material Properties vocabulary worksheet

• Aggregate material properties definition sheet

• Properties of Aggregates worksheet (2 versions provided)

4. Instruction plan

1. (2 min) Attention grabber: Start off class with a skit of a factious phone call with one person trying to describe a new material.

Sample:

Person one: (answering phone) Hello?

Person two: Madam! We have just discovered this brand new material, its awesome and we are going to build rocket ships out of it.

Person one: So tell me about this material, what are its properties.

Person two: It’s great. Better than all the rest.

Person one: Well is it Ductile?

Person two: It’s better than ductile; this will fly better than any duck.

Person one: Well is it ferrous?

Person two: Of course, this material is ferrous, ferrous good.

Person one: Then is it elastic?

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Person two: Sir I’m building rocket ships, not sweat pants.

Person one: Well is it conductive to electricity?

Person two: Let me check (yelps) Very well sir.

Person one: What about its thermal properties?

Person two: This material is hot!

Person one: Well, you really haven’t told me anything. In fact, I’m scared about this rocket ship. Where are you building it?

Person two: In your backyard.

Explain to students that to effectively communicate material properties there are some vocabulary terms they should be familiar with.

2. (< 5 min) Introduction: recall yesterday – learned about concrete, ingredients in concrete, (cement, water, sand and gravel – cement and water critical for making “concrete,” sand and gravel really just fillers to reduce the cost.) Today, we need to figure out how to add non-biodegradable waste materials to the mix, both to get rid of the waste and also to create strong and durable concrete.

note: this lesson contains 2 versions of material properties definitions and worksheets. One is for a

basic technology curriculum (‘material properties vocabulary and worksheet’) and the other is more

geared to properties of concern when making concrete (‘physical properties of aggregates,

definitions and worksheet’). Use the one that suits the needs of the particular class. Either way,

conduct the class in the same manner – brainstorm/possible waste aggregates, go over the

definitions to make sure students understand, do the activity - look/feel waste materials and examine

properties of each, then regroup to discuss the suitability for using as concrete aggregate and why.

You may want to briefly discuss the importance of material properties to selecting a suitable waste

material (or any material to use in any project – give examples), then distribute the definitions

worksheet and fill in as a class, then split into groups and distribute the waste aggregates and have

groups complete the back side of the worksheet. In other words, skip the brainstorm. Could also set

up stations around the room with the different waste aggregates and have students circulate with

their worksheets.

3. (10 min) Waste aggregates – brainstorm

How could we incorporate solid waste into concrete? Lead students to the conclusion that we can use waste products as coarse and/or fine aggregates. We can’t just add more inert material to the concrete mixture or the strength of the concrete will be compromised. What kind of waste can be used as coarse aggregates? What kind of waste can be used as fine aggregates? As students respond with answers, all of them should be written down on the board. At the end we can briefly discuss which ones are great waste aggregates. Criteria – size, durability, strength, hardness. Want non-biodegradable materials so they will not decompose in the concrete.

After the class is finished brainstorming which waste aggregates can be used, we will bring out samples of all the waste aggregates we have in little pails or cups. We will let students look and feel all of them, first handing out the waste fine aggregates, then collecting them, then handing out the waste coarse aggregates. Don’t collect them until we discuss what would make a good waste aggregate. Here are some questions to spark discussion. How do these aggregates feel different? Which of these do you think would make a good waste aggregate?

4. (5 min) Material Properties Overview

43

a. Explain to the students that the properties of aggregates are critically important for creating a strong and durable concrete product.

b. Divide students into groups. Hand out the appropriate version of the Material Properties definitions worksheet, and have transparency up on board (if doing material properties, provide additional red information, but not examples – have students fill in examples as homework or during extra time in class).

5. Activity

Note: depending on the time available and the class size, this activity could be done in 2 possible

ways – one would be to set up stations around the room with the different materials and have kids

rotate among the stations and fill in their worksheets. Another way would be to split the kids into

groups and give a few samples to each group, then have them report back to the class about their

materials and a recommendation as to whether the material would make a good waste aggregate.

a. (10 min) Properties of Aggregates (use one of the 2 worksheet versions provided, depending on what you have for materials). Do either as stations or by groups, as described above.

b. Have students identify the material properties of each of the samples they examine and complete the worksheet.

c. Save time at the end to go over all samples together as a class.

6. Wrap up –

a. Answer the questions on the worksheets as a class.

b. Summarize what was learned (share information from the activity, share opinions about which materials would be good waste aggregates) – waste materials used as aggregates, material properties are important, many wastes have suitable material properties to be used as aggregates.

c. Ask students – based on what they did, which aggregates do they think will work best and why. How can we choose the best among these possibilities? Answer: we need to do some testing!!

d. Important – tell students to brainstorm at home about waste materials that they want to try, encourage them to bring in a sample (about 1 cup) of a waste material, ready to mix into concrete (e.g., cut up milk jugs, shredded newspaper, wood stove ashes, coffee grounds, etc…)

44

Material Properties Vocabulary Worksheet Name: ____________________________

Ductile materials Materials that can bend and be deformed without breaking.

Brittle materials A brittle material will not deform without breaking.

Elastic materials An elastic material can be bent and it will return to its original shape.

Plasticity Plastic materials can be bent and they will stay bent.

Strength Strength refers to the materials ability to retain its own shape while a force is being applied.

Toughness Toughness is a materials ability to absorb energy without breaking.

Hardness Hardness is a materials ability to resist being scratched or dented.

Conductivity Conductive materials do not resist the flow of electricity, or offer very little resistance.

Insulating Insulating materials resist the flow of electricity. They are good for preventing heat loss from a building or protection from a conductor.

Magnetic Magnetic materials can be attracted to a magnet. Most can be magnetized or made to act as a magnet.

45

Material Properties Vocabulary Worksheet

(teacher version)

Ductile materials Materials that can bend and be deformed without breaking. Any material that can be pressed, twisted, or bent into shape has a high ductility.

mild steel, gold, fiberglass.

Brittle materials A brittle materials will not deform without breaking. opposite of ductile

window glass

Elastic materials An elastic material can be bent and it will return to its original shape.

Rubber bands, springs, and fishing rods

Plasticity Plastic materials can be bent and they will stay bent. The material we know as plastic gets its name from that characteristic.

Modeling clay, metals

Strength Strength refers to the materials ability to retain its own shape while a force is being applied. Strong materials are very difficult to bend, or shape.

Toughness Toughness is a materials ability to absorb energy without breaking

Animal leather, nylon, high density polymers, metals

Hardness Hardness is a materials ability to resist being scratched or dented.

Diamonds, High carbon steel, tungsten carbide

Conductivity Conductive materials do not resist the flow of electricity, or offer very little resistance. Most good conductors are metals

The very best is silver

Insulating Insulating materials resist the flow of electricity. They are good for preventing heat loss from a building or protection from a conductor. opposite of conductive

Wood, plastic, ceramic

Magnetic Magnetic materials can be attracted to a magnet. Most can be magnetized or made to act as a magnet. These materials must have iron in them or be ferrous.

steel

46

Worksheet: Material Properties of Aggregates Name:_________________________________________ Date:______ Directions: List the materials you have available as aggregates in the left hand column. For each material, place a check in the box of the properties that describe the material, using the terms from the definitions page. Feel free to examine the materials and ask questions.

Du

ctil

e

Bri

ttle

Ela

stic

Pla

stic

ity

Str

eng

th

To

ug

hn

ess

Har

dn

ess

Co

nd

uct

ivit

y

Insu

lati

ng

Mag

net

ic

Questions: Which properties would best suite a concrete aggregate? Which of the above materials contain these properties?

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Physical Properties of Aggregates: Definitions Name: ____________________________

Bulk Density

When this aggregate material is put into a container, how much does it compact? Material that compacts a lot has high bulk density, meaning there are few “void spaces” (empty spaces). Fine aggregates will have greater bulk density than coarse aggregates, because the particles are smaller – use bulk density to determine whether an aggregate is fine or coarse.

Specific Gravity How dense is this material? Does it sink or float in water? Density is important when considering the ultimate use of the concrete (do you have to lift or move the object around?)

Particle shape and surface texture

An ideal aggregate will have a rough surface texture and an irregular shape, so the particles will hold together. Smooth, rounded shapes will not hold together as well.

Shrinkage Is this material likely to shrink when exposed to wetting/drying cycles? Aggregates that shrink will result in a concrete that cracks and breaks.

Absorption, surface moisture

When you wet the surface of this aggregate, does the water absorb or bead up on the surface? Materials that absorb moisture will not be as good for concrete aggregates, we don’t want the concrete to absorb moisture – this increases the chances for cracking and breaking.

Resistance to Freezing and Thawing

This is related to absorption. Materials that absorb moisture are less resistant to freezing and thawing (the water freezes and expands, creating cracks in the concrete).

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Worksheet: Physical Properties of Aggregates Name:_________________________________________ Date:______ Directions: Write the name of the aggregate samples you are given in the left column (“material”). With the help of the descriptions on the physical property definition sheet, indicate in each column how this aggregate fits the particular physical property listed. (one example is done for you)

Properties

Material

Bulk Density

Specific Gravity

Particle shape and surface texture

Shrinkage Absorption, surface moisture

Resistance to Freezing and Thawing

Marbles low High Smooth, round

None None high

Based on your observations, which waste materials might be suitable to use as aggregates in your concrete mixture?

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Lesson 5 – Making concrete & safety


Engineers often need to measure material properties to help evaluate different alternatives. We have defined some alternative waste materials that may be suitable as aggregates in concrete; we now need to choose which ones we will use. Experimental measurement of the strength of concrete samples, prepared with the different waste aggregates, will help us to decide which materials are best. When we perform experiments to provide quantitative data for engineering design, we don’t have to form a hypothesis as in science experiments. Experimentation for engineering requires us to:

1. Determine what measurement we need to make and how we will make these measurements to provide the data we need for engineering decisions.

2. Define a matrix of experiments that includes all of the variables we want to test.

3. Perform the experiments to gather raw data.

4. Perform calculations and present data – often in a graphical fashion – to illustrate our findings.

5. Use the findings to help us make an engineering decision or design calculation.

In our case, we want to make measurements to determine the compressive strength of concrete made with various waste materials as aggregates. We must first make concrete samples with different aggregates so that we can test their strength when they have cured. We will need a matrix of aggregate mixtures so that we know we’ve tested all of the appropriate mixes.

Before the students make cylinders they should undergo a safety lesson and they should take the safety quiz. Safe work practices during experimentation protect yourself and others around you. By following the practices outlined in the handout, you make work more enjoyable and save yourself the aggravation of an injury and possible loss of work time. Employers look for workers who practice safe work habits.

Major Concepts:

Basics of Concrete Mixing

Measuring of Ingredients

Waste Material Reuse

Tools

Safety

Vocabulary Terms: Cement Concrete Mortar Portland Caustic


• Students will demonstrate safe work practices while working with cement.

• Students will be able to answer a safety exam to a 100% accuracy level before working with concrete.

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• Students will continue to formulate ideas on how to incorporate waste in the making of a valuable construction product such as concrete.

• Students will be able to use a variety of hand tools and machines to mix and pour concrete into cylinder molds.

Standards (days 5, 8 and 9 combined):

• NYS: 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 4.5 5.2, 6.6, 7.1, 7.2

• US Math: 4.1, 4.2, 5.1, 5.2, 5.3

• US Tech: 2.2, 3.3

• US Sci: 1.1, 1.2, 2.2

3. Resources

• Teacher resource: “Teachers guide – concrete products”

• Concrete Safety information sheet and quiz

• Concrete recipe worksheets

• Safety glasses, gloves

• 1 small cylinder mold per pair of students

• cooking oil – spray or bottled

• 1 Bucket per pair of Students

• 1 Spade per pair of Students

• 1 Measuring cup per pair of Students, or have several at each station

• 1 Rod per 2 pairs of Students

• Saran Wrap

• 2 Magic Markers

• 1 drop per pair of students of air entrainment solution

• Cement (5 cups per pair of students – amount depends on recipe)

• Water

• Lots of different samples of waste materials to test as aggregates! – need about 1 cup of

each, encourage students to bring in from home

• Coarse Aggregate, examples…. a. Shredded Rubber b. Shredded PVC – note, this needs to be snipped into short (1-2 cm) pieces. This can be

done ahead of time or have students do the day of mixing. c. Broken Glass d. Gypsum e. Glass marbles f. Shredded plastic milk jugs g. Shredded aluminum foil h. Wood Chips

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i. Paper j. Pea Stone

• Fine Aggregates, examples… k. Recycled Plastic l. White Glass powder m. Green beaded Glass n. Wood stove ash o. Saw dust p. Waste Sand q. Regular Sand

4. Instruction plan NOTE: the concrete test samples are best done using only one waste aggregate at a time – that is,

either sand and a waste coarse aggregate, or stone gravel and a waste fine aggregate. That way, all

the analysis (graphing compression strength, completing the weighted objectives table) can be divided

into fine or coarse aggregate, and the end result will be an ideal fine aggregate and an ideal coarse

aggregate.

ALSO: Make sure you have your recipes defined ahead of time and written on the board, so you can

easily assign students to recipes and keep track of what is mixed!

1. Introduction – briefly review the waste aggregates that we looked at yesterday. What step was that in the problem solving method? (think of alternative solutions). What is the next step in the problem solving method? (choose the best solution). But how do we make that choice? Need to gather more data. How can we gather more data about our waste aggregates? Today we will make some test samples to see how the aggregates work. Does anyone know why we might do this? Test if the mix holds together. But – what is an important property of concrete? Strength! So we will make small concrete test samples for testing the strength of the different mixes. “We have a lot to do today, so let’s get right to work!”

2. (5 min) Before we can work with concrete, we need to learn some safe practices. Display a list of safety practices to the class and go over the guidelines.

3. (3 min) Remove the safety guidelines and have a short discussion of the rules and their importance.

4. (5 min) Hand out a short quiz assessing the retention of the safety practices.

5. (2 min) Allow the students to complete the short exam. When all the students are done have the students correct the papers (go over as a group). Any students with an incorrect answer will have a short recap with the instructor and then be asked the question until they answer correct.

6. Before beginning the activity, make sure you go over everything while the students are still in their seats. Have the recipes already written on the board, with numbers (students will write the recipe number on their cylinder, along with their names).

7. (10 minutes) Tell the students they’ll be working in pairs. Each pair will be assigned a recipe number (have students number off 1-2-1-2, then just assign recipes when ready). **remember that the groups who uses the shredded PVC need to make sure the strips

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are snipped into short (1-2 cm) pieces. Tell the students that each pair will get a recipe worksheet and a cylinder - students should not leave the room until they have written down their recipe and number on their worksheet (along with their name and their partner’s name), and have labeled their cylinder (use a sharpie) with the recipe number and their names or initials. Also they should make sure that their cylinder has tape on the bottom over the hole, and is not cracked or broken.

Distribute dust masks, gloves and safety glasses to students. Have students write their names on their dust mask, tell them they have to save them to use again the next time we mix concrete.

Tell the students – when they begin, students should bring their recipe and their cylinder to the work area. Each pair of students should go to the first station and get a bucket and a trowel. Also at this station they should spray the inside of their cylinder with cooking spray (could also use a bit of oil with paper towels – just make sure the cylinders are well oiled). Then they should get all of their dry ingredients, by rotating to the different stations – they will need cement, coarse aggregate, and fine aggregate. Students will all put cement, coarse aggregate and fine aggregate into the bucket and will mix it well before adding water. Students should get help adding water, to make sure they don’t add too much at one time. Once the water is added the students should continue to mix until it is well mixed and ready to pour into the cylinders. ** don’t add too much water – start with half the recipe amount and get this checked by the teacher before adding more** (instruct students to write in how much water they ended up using). After the water has been added to every student’s bucket one of the teachers should add a drop of air entrainment solution to the mix, if desired.

Once their concrete is completely mixed, they need to get an OK from the teacher, then they can fill their cylinder mold. [students may need a demonstration on the rodding

part] They will pour the concrete into the cylinders in three stages. This means that a student will fill his/her cylinder a third of the way and then will rod the cement to uniformly mix it in the cylinder. NOTE: Students should not stir they should simple thrust up and down through the concrete mix. Then the student should add more of the mix until it reaches 2/3 to the top of the cylinder and should rod again. NOTE: Students should only rod the second 3rd of the mix, careful not to mix the first 3rd with the second. Then students should repeat for the remaining cylinder: topping it off, rodding it, then smoothing off the top, then sealing it with saran wrap so it will cure properly.

When they are done, students should bring their cylinder molds to the designated area. The bucket and trowel need to be rinsed out in the water buckets provided, or if weather permits, outside at the hose (no concrete down the drains!) Students should write any notes about their concrete mix on the recipe worksheets, then pass them in.

8. (15 min) Once all has been explained, have the students get to work! Monitor students closely, help with stations, help with adding water. It helps to have a few cups designated for water only, and have other cups designated to each station to avoid contamination of the different materials.

9. Wrap –up: Explain that the cylinders will cure, and then the different mixtures will be tested for compressive strength. Ask the students how they think we can test these cylinders for compressive strength, and ask them what strengths they think we will get.

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10. Clean up: NO CONCRETE DOWN THE DRAINS!!

NOTE: Allow ample amount of time for curing, at least 5 days!

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Table 1: Recipes for concrete – enough for 1 cylinder, 2” diameter x 4” high

(see teacher notes for additional recipes)

Coarse aggregate Fine Aggregate Cement Cylinder

# Type amount

(8 oz. cups) Type amount

(8 oz. cups) amount

(8 oz. cups)

1 Woodchips 1 Sand 0.75 0.75

2 Paper 1 Sand 0.75 0.75

3 PVC 1 Sand 0.75 0.75

4 Rubber 0.75 Sand 0.75 0.75

5 Stone 0.75 Recycled Plastic 0.75 0.75

6 Stone 0.75 Waste Sand 0.75 0.75

7 Stone 0.75 Green Glass 0.75 0.75

8 Stone 0.75 White Glass 0.75 0.75

9 Stone 0.75 Sand 0.75 0.75

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Making Concrete Test Cylinders

Names: ________________________________________

Cylinder #:____________________

Ingredient Amount added* Type

Coarse aggregate

Fine Aggregate

Cement ¾ cup

Water

* as measured with an 8 oz. cup

Making Concrete Test Cylinders

Names: ________________________________________

Cylinder #:____________________

Ingredient Amount added* Type

Coarse aggregate

Fine Aggregate

Cement ¾ cup

Water

* as measured with an 8 oz. cup

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Concrete Safety

Name :___________________________________ Date: _______ Teacher:__________________________________ Period:______ Directions: Circle the letter in front of the best possible answer.

1. Wet concrete is: a. Caustic b. Mild c. Hot d. Smooth

2. Prolonged contact with wet concrete can cause:

a. Skin irritation b. Eye injury c. Severe chemical burns d. All of the above

3. When working with concrete you should wear:

a. Safety glasses b. Long sleeves c. Water proof gloves d. Long trousers e. All of the above

True/false: Read each of the statements below and write a T in the space provided if the statement is true, and a F in the space provided if the statement is false.

4. ___ You should wear waterproof boots if standing on wet concrete. 5. ___ It is not harmful to breath in concrete dust. 6. ___ It is alright to leave wet concrete on clothing. 7. ___ Tight fitting glasses should be worn at all times during concrete work. 8. ___ Slight discomfort or skin irritation is not a reason to wash you hands. 9. ___ Caustic means that a chemical will burn the skin and eyes. 10. ___ A respirator filters air entering your lungs.

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Working Safely With Concrete/Mortars

Special precautions are necessary when working with concrete, mortars or cement. Prolonged contact between fresh, wet cement-based products can cause skin irritation and burns. These products are highly caustic and may result in skin injury if used improperly.

Please be aware of the following information from the U.S. Consumer Products Safety Commission and take the recommended safety precautions and suggestions.

WARNING: INJURIOUS TO EYES CAUSES SKIN IRRITATION

READ THIS WARNING BEFORE USING

Contains Portland Cement

Contact with wet (unhardened) concrete, mortar, cement or cement mixtures can cause skin irritation, severe chemical burns, or serious eye injury.

Avoid contact with eyes and skin.

Wear waterproof gloves, a fully buttoned long-sleeved shirt, full-length trousers, and tight-fitting eye protection when working with these materials.

If you have to stand in wet concrete, use waterproof boots that are tight at tops and high enough to keep concrete from flowing into them. If you are finishing concrete, wear knee pads to protect knees.

Wash wet concrete, mortar, cement, or cement mixtures from your skin with fresh, clean water immediately after contact. Indirect contact through clothing can be as serious as direct contact, so promptly rinse out wet concrete, mortar, cement or cement mixtures from clothing.

Seek immediate medical attention if you have persistent or severe discomfort. In case of eye contact, flush with plenty of water for at least 15 minutes. Consult a physician immediately.

Wear a well made respirator while handling dry cement dust. Do not breath in air-born cement dust or other fine particles.

KEEP OUT OF REACH OF CHILDREN

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Lessons 6 and 7 Foam Bridge Experiment- Forces and Stresses Lab

Background

All industrial and building materials undergo forces that they must withstand to function as designed. Concrete is strong under compressive forces, but not tension. Therefore reinforcing bars are added to improve the performance of concrete under tension.

Applying a force until the concrete fails and using our knowledge about compressive forces can be used to determine the strength of concrete.

This lesson will prepare the students for the experimental measurement of the strength of our concrete cylinders.

Force: a push or a pull. Newtonsinonacceleratimassforce ,×= or Pounds

Load: The overall force to which a structure is subjected in supporting a force

Compressive Force: Forces that press together

Tensile Force: Forces that pull apart

Stress: Force per unit area. ( Stress is not directly applicable to this lesson, better to bring this up when it is. When you first talk about your cylinders may be a better time.

)(,22

psiin

poundsor

m

newtonsofunitsin

area

forceStress =

This lesson will show the students the difference between compression and tension, how they affect the strength of concrete and some of its applications.

Concepts

NYS Standards

NYS: 5.2 US Sci: 2.2 US Tech: 5.7

Key Terms

Compression Tension Stress Force

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Instruction Plan

1. (5 min) Introduction a) Have students stand up and bend over at the waist, keeping their knees straight.

“Feel your back stretch, and feel the folds in your belly? Which is in tension? (back) and which is in compression?(belly)

b) Ask for two student volunteers. Have the students hold on to opposites sides of the rope (or a slinky). Have each student tug on their end of the rope (tug of war-like) to simulate tension. Have the students then push the ends together to simulate compression. (Optional)

c) What is a force? (Answer: a push of a pull, force is anything that can cause a massive body to accelerate)

d) Have students define tension and compression (draw on the board to show students better):

Tension: a pull Compression: a push

e) What are the units for force? (SI Units are Newtons; English Units are pounds. We will be using pounds for this activity.)

2. Tension and Compression Activity

There are a number of ways to do the following activity depending on the level of freedom you believe your students are capable of and/or time constraints.

a. Option 1: Completely Students Design - some discussion needs to take place before materials are distributed (should be appropriate for 8th graders).

1. Explain that the foam is acting as the concrete deck (the part you drive across.)

2. Show them that ‘concrete’ alone is not strong enough by snapping a piece of the foam. They will need to reinforce their deck. Here is an appropriate time to discuss rebar and cabling that goes into concrete.

3. Split students into groups of 2-3.

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4. Give them 2-3 minutes in their groups to talk about an idea. 5. Distribute materials. Each student receives:

a. One piece of foam (~2.5”x12”) b. A 3/16 dowel cut to 12” c. A piece of string cut to ~16” (and 2 small dowels used for

tightening the string) d. 1 ft of masking tape

b. Partial Design

1. Explain that the foam is acting as the concrete deck (the part you drive across.)

2. Show them that ‘concrete’ alone is not strong enough by snapping a piece of the foam. They will need to reinforce their deck. Reinforcing can be placed either taped to the outside or in a cut out on the bottom of the deck.

a. Use the dowel as a reinforcing rod. b. Use the Sting and two small dowels as post-tension.

i. By putting tension on the string that is being used for reinforcement that allows a higher load to be on the deck before failure.

3. Split students into groups of 2-3. 4. Give them 2-3 minutes in their groups to talk about an idea. 5. Distribute materials. Each student receives:

a. One piece of foam (~2.5”x12”) b. A 3/16 dowel cut to 12” c. A piece of string cut to ~16” ( and 2 small dowels used for

tightening the string) d. 1 ft of masking tape

3. (10 min) Discussion- while discussion is ongoing or before or after, make an “ideal”

bridge by combining a number of the students ideas and checking out what worked for them best, or make one before hand and share with the class during the discussion.

a) Have students share the weight on their deck b) Ask closure questions: c) “What other materials are strong in tension?”

Ans: Steel, list others d) “What other materials are strong in compression?”

Ans: Concrete, list others

REBAR POST TENSION

<= before loading <= after loading

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e) “How will we test our concrete cylinders? (In tension or compression.) And why are we testing it that way?” Ans: We test concrete in compression because it is strongest in compression. It is never used solely in tension.

f) Show the elephant video. (This is a link off of a teacher website, but it cannot be saved)

http://www.teachersdomain.org/resources/phy03/sci/phys/mfw/bbarch/index.htm l

On the right hand side of the screen, under Multimedia Resources Used in This Lesson, it is “Arch Bridge.” You don’t have to be registered, just select a “test drive” when prompted. g) Why do we care about tension and compression?

i. Explain that “engineers need to know how much weight their concrete can hold before they can build a bridge or building.”

ii. Instead of building a bridge and testing how many cars can go across it, then making it stronger next time, they mix a test cylinder using the type of concrete they plan to use, just like what you did.

iii. Then they crush these cylinders using a hydraulic press to see how much force it takes to crush them.

4. Does the strength of the cylinder equal the strength of the bridge? No, not really. To

compare, engineers divide the force by the cross-sectional area to calculate Stress.

a. Stress = force/unit area

b. Example – show 2 shoes, one with a large flat heel (or a sneaker) and another with a small, spiky heel. If I stand in each shoe, will the force I put on the floor be different? (no, it will be the same because I weigh the same in both shoes). Will the stress be different? (yes, since the cross sectional area of the spike heel is so much smaller, the stress will be much greater with this shoe – that’s why ladies can poke holes in soft floors with their heels!)

c. Units: In English units: psi (pounds per square inch) In SI units: N/m2 NOTE: We only use psi in this activity

5. Stress Calculations (Optional – could be done as a class on the board) a. Hand out the “Stress Calculations” worksheet and fill it out as a class. b. Emphasize to the students that stress is only a function of area and force

(not of depth of an object, the 3rd dimension doesn’t matter.) c. Hand out “Stress Homework” sheet for homework.

6. Assign the “Stress Homework” due next class. Tell them this will help to understand the crushing of the cylinders that they made, and the test at the end.

7. Conclusion Questions: a) What is the difference between stress and force? b) What have we learned about stress? c) How does stress apply to our daily lives?

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Activities

Imitation Bridge Deck

Supply list

1) Foam Pieces (12” long x ~2.5” wide) 2) Dowels 12” long 3/16” diameter 3) String 16” long 4) Two piece dowel ~1.5” long to apply the tension to the string 5) Bucket 6) Small Cup 7) Large amount of sand.

Resources http://www.teachersdomain.org/resources/phy03/sci/phys/mfw/lp_tension/index.html

Reflective Notes

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Stress Calculations

1) How do you calculate the area of a circle? __________________________

2) How do you calculate the area of a square? ________________________

3) How do you calculate the area of a triangle? ________________________

4) Calculate the area and stress of the following shape:

Assume that there is a 20 pound load pushing on the shape.

Area ________________________________ Stress________________________________

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Stress Calculations (TEACHER)

1) How do you calculate the area of a circle? π x r2

2) How do you calculate the area of a square? Length x width

3) How do you calculate the area of a triangle? (base x height) / 2

4) Calculate the area and stress of the following shape:

Assume that there is a 20 pound load pushing on the shape.

Area __28.27 in2_______________________ Stress__0.7074 psi_____________________

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Imitation Bridge Deck Activity

Purpose In order to understand how force affects concrete, we must first understand that force affects objects differently. In an actual concrete deck there are parts of the concrete under tension and parts under compression. As you know concrete does not withstand high forces of tension. Therefore reinforcement must be added. Your job in this activity is to come up with a way to allow your deck to withstand a larger force.

Equipment

1) Activity Sheet 2) Foam deck 3) Dowels 4) String 5) Tape

Procedure 1. Before you begin the actual construction sketch some ideas for your deck in the space

provided. 2. Next put your idea into action. With the materials provided build your deck. 3. Once you have your final design built you will put your deck up against the other

designed decks in class. 4. As a class you will place your deck where you are instructed so that a bucket can be

placed under the deck and filled with sand until failure. NOTE: In this class we will say that failure is when your foam deck breaks. However in the real design and testing stage for engineers we say failure has many stages and each one is documented. SKETCHES:

Total weight of bucket and sand: _________________________________lbs

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Teachers Notes for Activity The amount of design that you let the students do is up to you. Regardless, make sure that before they begin they know:

1. Compression 2. Tension 3. Where and what the deck of a bridge is – the part that you drive across 4. Foam is acting as the concrete. It is not sufficient to hold a significant load.

a. Snap a piece of foam with little effort and explain that this is why you need to add reinforcement.

5. Make sure that they understand how one object can have different parts in compression and tension. Draw the rectangle representing the deck and show its deflection, as seen in the instruction plan. Don’t just tell them this, see if they can correlate this to when they bent over to touch their toes in the beginning of this lesson.

6. Also at the end during the loading, they can test to complete failure, or when the foam snaps. However they should know that when beams are tested by engineers, they are still tested to when they crush, but each pahse of failure is documented. In concrete you are able to see the onset of cracks and their progression. This is similar to noting when their foam begins to bend.

During the design and construction phases, they can place the reinforcement either taped to the outside or they can create a ‘gouge’ in the bottom and place the dowel or string in that. This would more similar to the actual cases where reinforcement is placed in the lower half of the deck. To load the deck you need to:

a. Set up the deck between two level planes with approximately two inches on each side, leaving about eight inches clear in the middle.

b. Next place a small flat object in the center, a small black lego plate works great. This allows for the load to be distributed along that distance, instead of a point load where the bucket is hung.

c. Then place the bucket so that it is in the center of the foam and the ‘load distributor’ and hanging freely below.

d. Finally you can begin to add sand to the bucket. Remember that you are loading until the foam breaks. Therefore one of the students in the group should keep their hands around the bucket so that when it breaks the sand stays in the bucket.

e. Lastly weigh the bucket and record on the activity sheet. During the conclusion of this activity compare the weights of each group and the respective designs and their effects. *Post-Tensioning – this allows for a larger load to be placed over the deck. This works best in a ‘gouge’ or inset in the deck. Use the small dowels to hold and tighten the string to apply the tensile force. See the illustration in the instruction plan. It will still fail by the same way as the dowel, but could hold a larger load. A similar case is the trailer flat bed semi truck. If you look at one with out anything on it, it bows up because of the axial tension on the bed.

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Name_____________________________________________

Homework- Stress

Directions: Calculate the area and stress for the following shapes. Assume there is a 20 pound compression force applied to the shapes. Show all work and include units on your answer. 1.)

Area __________________________________ Stress ________________________________ 2.)

Area __________________________________ Stress _________________________________

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3.)

Area ________________________________ Stress _______________________________

Directions: Calculate the stress of the following object. The circle has a 4 inch diameter and the compression force applied to the cylinder is 20 pounds. Show all work and include units.

Area ________________________________ Stress _______________________________

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Name_____________________________________________

Homework- Stress (TEACHER)

Directions: Calculate the area and stress for the following shapes. Assume there is a 20 pound compression force applied to the shapes. Show all work and include units on your answer. 1.)

Area _____16 in2________________________ Stress ___1.25 psi_______________________ 2.)

Area ____12.57 in2_______________________ Stress ___1.59_psi_______________________

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3.)

Area ____8 in2_________________________ Stress ___2.5 psi_______________________

Directions: Calculate the stress of the following object. The circle has a 4 inch diameter and the compression force applied to the cylinder is 20 pounds. Show all work and include units.

Area _____16 in

2_______________________

Stress ____1.25 psi_____________________

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Lesson 6&7- Spaghetti Lab- Alternative to Foam Bridge Lesson


All industrial and building materials undergo forces that they must withstand to function as designed. Concrete is strong under compressive forces. Reinforcing bars are added to improve the performance of concrete under tension.



Force: a push or a pull. Newtonsinonacceleratimassforce ,×= or Pounds




Stress: Force per unit area. )(,22

psiin

poundsor

m

newtonsofunitsin

area

forceStress =

This lesson will show the students the difference between compression and tension and how they affect the strength of concrete. On the first day they do a lab activity and collect data. On the second day they analyze their data by making plots – either by hand or using Excel. Students will make scatter plots using the measured data, and then they will add a trend line and be able to interpolate and extrapolate from these graphs. Major concepts

• Tension: the force applied when something is pulled apart

• Compression: the force applied when something is pushed together

• As a (spaghetti) column gets shorter, it will handle more weight.

• Trend line: a line on a graph indicating a statistical trend

• Interpolate: To estimate a value of (a function or series) between two known values

• Extrapolate: to estimate by extending or projecting known information

• Independent variable: a manipulated variable whose value determines the value of the other variables

• Dependent variable: a variable whose value is determined by the value assumed by an independent variable

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• Students will be able to distinguish between tension and compression and provide examples of each.

• Students will be able to apply the concepts of tension and compression to concrete by measuring these properties in samples of pasta.

• Students will be able to calculate compressive and tensile strength.

• Students will be able to create scatter plots with a trend line and be able to analyze these.

• Students will be able to interpolate and extrapolate (data) from the graphs.

• Students will become familiar with Microsoft Excel graphics program.

Standards:

• NYS: 5.2

• US Sci: 2.2

• US Tech: 5.7

3. Resources

• PowerPoint file – “Concrete used as a construction material with pictures”

• Student Handout or Homework – forces and stress

• Item to demonstrate tension/compression: pool noodle or flexible lumber

• 2 Spaghetti strength test apparatuses (tension and compression test apparatus) borrow

from CE department until we make our own set.

• spaghetti

-- tension – strengthened with pieces of spaghetti and hot glue.

-- compression – regular pieces of spaghetti cut to length.

• rulers

• Kitchen scale (measures high enough for bucket of sand, about 10 lbs)

• Cylinders from strength test

• Spaghetti strength data sheet

• Calculators

• Computers (in lab)

• Excel instruction sheets

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• Diskettes (one per student)

4. Instruction plan

Day 1:

• PRIOR to class: prepare several pieces of spaghetti, of different lengths (use 3 or 4 lengths, 8 cm, 10 cm, etc…). Make several pieces of each length for taking replicate measurements and also to have extras in case the test fails. Separate the pieces of spaghetti so you have several of each length for the compression test, and several of each length for the tension test.

For the tension test, use a hot glue gun to glue two short pieces of pasta to each end (about 1.5-2 inches) for reinforcement (to make the ends thicker, where they connect to the apparatus). When gluing the extra pieces to each end make sure that they are glued so that the entire piece lays flat.

Go through several trials for both the compression and tension tests beforehand so you know how the apparatus works.

1. (Possible attention grabber – have an overhead or slide showing examples of tension (rope) and compression (squeezing) as students enter room. Could also use a pool noodle and bend back and forth. See teacher resources.) Write TENSION and COMPRESSION on the chalkboard. Ask if anyone can define these terms. Ask for examples of objects in (and out of) the classroom that would be in tension or compression.

Compressive force – squeezing force that pushes and tries to compact

Tensile force – pulling force that tries to stretch out and pull apart (when a tensile force is acting on an object it is under tension).

More examples: tension: plant hanging from ceiling, cable that supports the load of a crane; compression: a person sitting on a couch.

Have students stand up and bend over at the waist, keeping their knees straight. “feel your back stretch, and feel the folds in your belly? Which is in tension? (back) and which is in compression?(belly)

2. What is a force? A force is a push (compression) or a pull (tension) that acts on another object. Force is measured in Newtons (or, in English, pounds)

Note: could move the discussion (3 and 4) to second day so the lab could be more of a

discovery.

3. Why do we care about compressive and tensile strength?

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a. Explain that “engineers need to know how much weight their concrete can hold before they can build a bridge or building.”

b. Instead of building a bridge and testing how many cars can go across it, then making it stronger next time, they mix a test cylinder using the type of concrete they plan to use, just like what you did.

c. Then they crush these cylinders using a hydraulic press to see how much force it takes to crush them.

4. Does the strength of the cylinder equal the strength of the bridge? No, not really. To compare, engineers divide the force by the cross-sectional area to calculate Stress.

c. Stress = force/unit area

d. Example – show 2 shoes, one with a large flat heel (or a sneaker) and another with a small, spiky heel. If I stand in each shoe, will the force I put on the floor be different? (no, it will be the same because I weigh the same in both shoes). Will the stress be different? (yes, since the cross sectional area of the spike heel is so much smaller, the stress will be much greater with this shoe – that’s why ladies can poke holes in soft floors with their heels!)

5. Based on your internet research, do you think concrete performs better in compression or tension? (compression). What about spaghetti – do you think spaghetti is stronger than concrete? (actually, in tension, it is!)

6. Break the class into two groups. Have half the class do the compression testing while the other half is performing the tension test. Have students switch groups when completed, so each student gets to do both tests. If time is short, have students work in pairs and assign each pair to measure the tension/compression strength of one length of pasta, then can combine data at end.

Tension Test

a. Have one student measure the length of the spaghetti (actual length is between the supports on the apparatus) and record the data.

b. On one end off the apparatus there is a clamp with a pad on the top and bottom. Put the ends of the spaghetti into the clamps so that the bar is approximately level. This may require you to adjust the center bolt. Next place the small bucket in the groove opposite the clamped-in spaghetti.

c. Slowly add sand until spaghetti breaks, making sure that someone has their hands under the bucket, not holding it up but so that when the spaghetti breaks and the bucket drops someone is there to catch it.

d. NOTE: if spaghetti breaks where it is attached to the apparatus, the test failed and should not be counted. Spaghetti should break somewhere near the middle.

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e. Weigh the bucket and the sand on the kitchen scale (in pounds) and record value. This is equal to the tensile load.

f. Repeat for different lengths

-Also possible is to have each group do different lengths and report their findings to the class – to save time.

Compression Test

a. Have one student measure the length of the spaghetti. The lengths should be about the same as the lengths for the tension test. Record the data

b. Place spaghetti vertically in test apparatus. There are small holders, on the same side as the groove for the bucket, so that the spaghetti doesn’t slip.

c. Place one student at eye level in front of apparatus, and two others on opposite sides (so spaghetti can be viewed from all three directions) – it helps to have many looking at the same time.

d. Add sand to bucket (won’t be very much) until you see spaghetti buckle (bend) out of place.

NOTE: If spaghetti breaks then it doesn’t count, we are looking for the moment it

buckles out of plane.

e. Weigh the bucket and sand on the kitchen scale (in pounds) and record value. This is equal to the compressive load.

f. Repeat for different lengths, similar to the tension test.

7. Wrap up 5 minutes before class is over.

a. Look at the data.

b. Ask how did spaghetti behave under compression? (tell them to look at their numbers, were the numbers high, or low?) Answer: poor

c. Ask how did spaghetti behave under tension? (look at numbers, are they high or low?) Answer: Good

d. Conclude that spaghetti is good in tension and bad in compression. We know that concrete is good in compression but not in tension. So why not mesh the two materials together?

e. Well that’s exactly what engineers did

f. Spaghetti acts just like steel

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g. So when a building or bridge is made or concrete it is reinforced with steel bars called rebar so that it can stand compressive and tensile forces

8. If there is time, students should convert their load data to stress (divide pounds by cross-sectional area, to get psi). If there is not enough time, can do this as homework or as part of data analysis next day.

9. Collect data sheets. Remind students to meet in the computer lab next class and bring data sheet to plot data.

Day 2:

1. Quick review of previous day: “What is compression? Tension? Why do engineers put steel cables in concrete?” Expect answers like “steel is used in concrete as reinforcement since concrete is weak in tension and strong in compression where as steel is strong in tension and weak in compression,” etc.

2. Have students get out their length/weight data sheets. Tell students that today we will be making graphs of the data that they collected.

3. If it was not gone over the previous day, explain the difference between force and stress – they measured force, but you need to divide by the cross-sectional area to get a value for stress. (why is stress important? It gives us a strength-per unit area, so we can compare the material itself without worrying about different sizes.)

4. Make sure that everyone has done the calculations – if not, finish up the calculations! (could also do these on excel, have students enter in load data and divide whole column by area to get psi) Explain that being an engineer/scientist, data is gathered on a regular basis (like what you all did yesterday). Not everyone understands what the data mean. Graphs help organize data and make it meaningful. Last class you all took data, but you may not have understood what the data represented. The graphs you will make today will show you the importance of the data you gathered.

3. Have students look at their data sheets and observe the type of data collected. “In the lab we took different lengths of spaghetti and we saw how much force was needed to make the pasta break.

(NOTE: even though we used a scale, we measured force, in pounds. If we were

using metric, we’d measure mass then have to convert to force by multiplying mass x

acceleration due to gravity. Students may be confused, just be aware of this in case it

comes up.)

One of the tools we can use to look at data in a different way, to analyze relationships and try to understand what is happening, is to make a graph. That’s what we are doing today. So on our data sheets we have two variables-can anyone tell me what the variables are in each experiment”? (The length of the pasta and the stress that it supported.)

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4. Instructor should draw an x and y axis on the board –“If this is my graph, which variable should I put on the y-axis?” (Hint: What did we actually measure?) (the stress or load in psi-don’t forget the units!!) Does anyone know what the y-variable is called? (The dependent variable) It is called the dependent variable because its value changes, depending upon what the value is for x. So what do we put on the x-axis? (Length of spaghetti in cm or inches). This is the independent variable; we didn’t measure this- we were already given this in experimental setup”.

5. Break the class into 2 groups, -one group will graph the compression data, the other will graph the tension data (make sure that all the data are the same – i.e., compression data are the same, and tension data are the same). Let the students work either on their own, if there are enough computers, or in pairs if there aren’t not enough computers. Hand out worksheets with excel instructions to each student. **it helps immensely if there are teachers to guide each group of students through making the graphs.

6. Have students log on to computers and go to start menu, programs, then excel.

a. Type in the length of spaghetti in one column

b. In another column type in the load, in psi, either for the compression or tension tests, depending upon which group they are in. (note: if students have not calculated stress, have them type in load, in pounds, then divide whole column by area to get stress, psi)

c. Highlight the length column, hold down control button and highlight stress column (make sure students are able to do this, they may need help, so pay attention)

d. Go to insert chart, XY Scatter, Scatter (no lines connecting points), NEXT, NEXT

e. Go to titles, Type in Chart title name (Compression: Length of Spaghetti vs. Stress), X axis name (Length of Spaghetti, cm), Y axis name (Stress, psi), NEXT

f. Save as chart in new sheet, FINISH (see example below)

Compression: Length vs Force

0

20

40

60

80

100

120

2 4 6 8 10 12

Length of Spaghetti (cm)

Fo

rce(g

/cm

3)

78

7. Once students have set up their graphs, have them add trend line. On sheet with graph, right click on any data point, add trend line, linear, OK

8. Have students save their graphs to disk provided, (put their names on them) print out their graphs. Time is limited so if you are only able to get this far, start to wrap up and talk about interpreting their data without printing out the graphs.

9. Bring students together to briefly discuss the data trends, what happens as the spaghetti gets shorter (it carries more load). Is the same behavior seen for both compression strength and tension strength? (Yes, it should be) Extend discussion to interpolation/extrapolation as seen below.

10. Once this is done, ask, “What if we want to know how many pounds a 16 cm piece of spaghetti would hold? How would you find this out? Would you just guess? Would you have to test it out? Is there a quicker way that we can find out right now?” Answer = follow trend line (i.e., use a ruler, draw a vertical line at x=16cm to trend line, from trend line draw a horizontal line to y axis, that is how many pounds that length of spaghetti will hold.)

11. If time permits, give more extrapolation/interpolation exercises (How long would the piece of spaghetti have to be to hold 63 lbs? How many pounds could a 3.5 piece of spaghetti hold?)

12. Share graphs made between the two groups.

13. If desired, distribute homework on compression and tension.

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Name:___________________ Date:_____________

Spaghetti Strength Test

Compression Test

Length of

Spaghetti (in)

Diameter

of

Spaghetti (in)

Area of Spaghetti 2

2*

=

DiamA π

(in2)

Weight of Sand and Bucket (lbs)

Stress (Weight/Area) (lbs/ in2)

0.0625 0.0625 0.0625 0.0625 0.0625 0.0625 Tension Test

Length of

Spaghetti (in)

Diameter

of

Spaghetti (in)

Area of Spaghetti 2

2*

=

DiamA π

(in2)



0.0625 0.0625 0.0625 0.0625 0.0625 0.0625

80

Name:___________________ Date:_____________

Spaghetti Strength Test- Class Results

Compression Test

Length of

Spaghetti (in)

Diameter

of

Spaghetti (in)

Area of Spaghetti 2

2*

=

DiamA π

(in2)



0.0625 0.0625 0.0625

0.0625 0.0625 0.0625 Tension Test

Length of

Spaghetti (in)

Diameter

of

Spaghetti (in)

Area of Spaghetti 2

2*

=

DiamA π

(in2)



0.0625 0.0625 0.0625 0.0625 0.0625 0.0625

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How to use excel to create a chart

o Log on to computer o Go to Start Menu

� Programs

� Excel o Type in the length of spaghetti in one column o Type in the load (in psi) in another column o Highlight the length of spaghetti column by holding down left mouse over all the values o Hold down the control button and highlight the load column o Go to Insert Chart

� XY Scatter � Scatter (no lines connecting points) � NEXT � NEXT

o Go to Titles, type in Chart Title Name, X axis name, and Y axis name o Save chart as a New Sheet

How to add a trend line o Go to Chart 1 o Right click on any data point o Add Trend Line

o Linear o OK

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Lesson 6 – Forces and Stresses – the shorter (lecture based) lesson for tension and compression


All industrial and building materials undergo forces that they must withstand to function as designed. Concrete is strong under compressive forces. Reinforcing bars are added to improve the performance of concrete under tension.



Force: a push or a pull. Newtonsofunitsinonacceleratimassforce ,×= or Pounds




Stress: Force per unit area. )(,22

psiin

poundsor

m

newtonsofunitsin

area

forceStress =

2. Performance Objectives

• Students will be able to describe and give an example of a compressive force and a tensile force.

• Students will be able to calculate compressive strength.

Standards:

• NYS: 5.2

• US Sci: 2.2

• US Tech: 5.7

3. Resources

PowerPoint file – see “Teacher resource – concrete used as a construction material with pictures”

• Student worksheet *2 versions available* – Forces & Stress (homework for this lesson)

• PowerPoint file – see “Teacher resource – concrete used as a construction material with pictures”

• Two buckets, and a 2x4.

• Pool noodle

4. Instruction plan

1. (5-7 min) Introduction

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Grab the students’ attention with a very obvious demonstration (something they can easily relate to) of a material that has either a high compressive or high tensile strength, but not both, like a rope. Example: First, ask the students if they think the rope is strong. Then relate that ropes are used for towing very heavy things, or for rock climbing, etc. Show them how strong a rope can be by pulling a desk with one, or by playing tug-of-war with a student or instructor. They ARE very strong in that sense. But then ask them what would happen if you tried to support a pile of books with that same rope. Drop a book on the rope when it is placed on its end – of course it comes crashing down. Explain that this is due to different properties of the rope, and the different FORCES being applied to the same MATERIAL, and that today you are going to learn about the different forces of COMPRESSION, and TENSION, and how they will affect a CERAMIC MATERIAL like the concrete we are making. Make the point that it is important to understand such things when you are applying technology

to BUILD or ENGINEER something, so that your structure is safe, and long-lasting.

2. (10 minutes) Students should first be introduced to the definition of a force. A Force is a push or a pull that acts on something – mathematically,

onacceleratimassforce ×= .

In SI, or metric units , force is measured in newtons. Mass is in kilograms (kg) and acceleration is in meters per second

2 (meters per second, per second)

(note: students will probably have difficulty understanding the units of acceleration. Define

acceleration = how fast something speeds up, or, the rate of change in velocity. Velocity is

in meters per second, so to convert that to a change in velocity it’s meters per second per

second, or meters per second squared.

3. demonstration – have students stand up, a comfortable arm’s length apart. Have students imagine they are a concrete wall swaying in the strong wind (the wind is a force, pushing and pulling them). Then have them bend all the way over. “Fell the stretch in your back - your back “pulling apart” – that’s tension. Feel how your stomachs are all “pushed together” in rolls – that’s compression.” These are the 2 types of forces, tension and compression.

4. (3 minutes) Compressive forces. Again, begin by relating the definition to your first demonstration. Also give other demonstrations - a can is a great example for compressive forces. You can place a can on the ground and you can crush it demonstrating a compressive force. Concrete is really good with compressive forces so it is used all the time when building things. For example it works great as a column.

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3. (3 minutes) Tensile forces. A rubber band or such would be a good example for tensile forces on objects. Definition: Tensile force-forces that pull apart. Relate the definition to whatever demonstration you gave at the beginning of class. Students should be taught that concrete has zero tensile force and that is never used alone in society to withstand any kind of tensile force. If you want to use concrete and it is going to be subjected to tensile force rebar is needed to withstand the tensile force. Rebar are bars placed in the concrete before it hardens.

_________________________________________________

(for the mathematically inclined…) Ask the students: I am standing on the floor. Am I exerting a force on the floor? What kind of force, compressive or tensile? (compressive) How do we figure out how much force I am exerting? Force = mass x acceleration. I can measure my mass, right? What about acceleration, am I accelerating? Actually, there is an acceleration due to gravity – does anyone know what this means? The acceleration due to gravity is how fast something speeds up when it drops. Does anyone know how much the acceleration due to gravity is? Is it different, or the same, for different objects? (drop 2 objects – a ball and a crumpled piece of paper – they should both hit the floor at the same time.) So, the acceleration due to gravity is always the same. It is equal to 9.8 meters per second per second, m/s

2.

So, to calculate the compressive force, say I weigh 75 kilograms.

newtonss

mkgonacceleratimassForce 73681.9)75(

2=

×=×=

5. (8-10 minutes) If time is going well it would be good to teach the students about beams and what kind of forces act on them. Demonstrate with a 2x4 and 2 buckets, or a pool noodle, or something that bends rather easily so they can see tension on one side and compression on the other.

When a beam undergoes a force in the middle of the beam as shown below the beam undergoes both tensile and compressive forces. Where there are tensile forces in the beam rebar will be needed so the beam does not break. This will give the students a more in depth understanding of tensile and compressive forces. Bring in two buckets and a piece of wood for the students to stand on to demonstrate this effect. Have several volunteers come up and stand on the wood.

Force Compression

85

Then tell the students, since steel is good for tensile forces steel should be laid within the concrete to stand up to the tensile force on the bottom side of the beam. Since concrete is good for compression forces, concrete alone can withstand the top side of the beam. This is a great concept for the students to learn.

(either draw the diagram on the board or show a good PowerPoint slide)

6. (10-15 minutes) Stress.

Stress represents a force over the entire area of the surface. This will take a little longer

to explain because this is a little harder to understand. area

forceStress = . So when you

have something that exerts the same amount of force, the stress can change if the area changes. A good example is to show 2 pairs of shoes, with very different sized heels – one with a large, flat heel and another with a spiked heel. If the same person stands in each of these shoes, will the force be the same? (yes). Will the stress be the same (no). Which shoe will result in a higher stress? (the spiked heel, because the surface area is less).

Below is an example of a compressive stress.

Example (SI Units): If “Suzy” were to stand on this bucket and she has a mass of 50

kg, and the area of the bucket is 65 cm2, what is the stress on the bucket?

( )( ) ( ) newtonss

ftkgonacceleratimassForce 49181.950 =

== THEN

226.7

65

491

cm

newtons

cm

newtons

area

forcestress ===

7. wrap up. Why do we care about forces and stresses? We want to make sure that our concrete mix is strong – we’ve used a lot of different materials for aggregates, and we’ve examined the properties of the different aggregate materials themselves. One thing we still need to look at is, how good is the concrete mix? We can evaluate how it looks, how

Tension

86

heavy it is, and all that, but a very important property of concrete is how strong it is. We will test our concrete cylinders for compression strength.

8. (3-5 minutes) Briefly hand out the Forces and Stresses homework, explain the directions and tell them it is due tomorrow before we break cylinders (if that’s going to happen).

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(version 1) Name: ________________________ #1.) Circle the drawing below that represents a tensile force:

#2.) Circle the drawing below that represents a compressive force:

Directions: Circle the word that will make the sentence true:

#3.) Concrete can withstand high ( tension , compression ) forces.

#4.) A Newton is a measurement of ( mass , weight , force , stress ).

#5.) A kilogram is a measurement of ( mass , weight , force , stress ).

#6.) (circle one number and one set of units!) The acceleration due to gravity is equal to

(32.4, 98.8, 0, 9.8) (pound/acre, Newton/m2, meter/sec

2, mile/hour).

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Useful Information: We know the following information to be true.

Width

A. ( ) )(heightwidthArea ×=

Height

B. Area

ForceStress =

#6.) Calculate the area for the square shown below

5 meters

6 meters

#7.) Calculate the stress for each force below using an area of 30 m2

EXAMPLE

a.) Force = 300 newtons

2210

30

300

m

newtons

m

newtonsStress ==

a.) Force = 600 newtons

b.) Force = 1200 newtons

89

Name:__________________________________ Date:_______________________________

Force, Area, & Stress Worksheet (version 2)

For a circle, the area is calculated as:

2

2

=

dArea π

Where π=3.14 Calculate the following areas, show all your work:

d (inches) Area (inches2) 4

8

10

For a rectangle the area is calculated as: ))(( wlArea =

Calculate the following areas, show all your work:

L (inches) W (inches) Area (inches2) 2

4

8

10

5

20

d

w

l

90

Stress is calculated as: Area

ForceStress = where the units are

2in

Pounds. An object’s strength is

related to how much stress it can support in either tension or compression. Objects which can

support a large amount of stress are said to have high strength.

Fill in the chart below showing all your work:

Object Loading Area (Inch2) Force (Pounds)

Stress (PSI)

2 inch diameter Concrete Test Cylinder

Compression 3140

1 inch diameter rope

Tension 1000

36 inch square block

Compression 12960

0.5 diameter inch wire

Tension 400

Label the drawings as being in either “tension” and “compression.”

_______________________ _______________________

Concrete can withstand high ______________________ forces.

91

Lesson 8 – Testing Cylinders for Compressive Strength


This lesson requires the students to generate data quantifying the strength of their cylinders. These data will be used to help with the engineering decisions required to determine the best aggregate to use. Students should have some understanding that force can be used to determine the strength of a material.

Until now we have been consistently using metric, or SI, units. At this point it may help to introduce students to the English units used for force and stress, since many of the everyday applications that the students are familiar with may be given in English units (e.g., tire pressure, in pounds per square inch, psi).

Compression force (newtons or pounds)

Load (newtons or pounds)

Stress = Load/Area ( )(22

psiin

poundsor

m

newtons)

Students will be given the opportunity to break test cylinders at an appropriate concrete testing facility, and will learn how to record data. If this opportunity is not available, teachers should arrange to test the students’ cylinders and bring the data to class. A video recording of the testing procedure is available, and should be shown to the students so they understand the procedure.


• Students will demonstrate appropriate use of industrial tools.

• Students will be able to describe how the strength of concrete is tested.

• Students will be able to measure the diameter of a cylinder end and, from this information, calculate the surface area of the cylinder end.

• Students will be able to calculate stress from measurements of applied load and area.

Standards (days 5, 8 and 9 combined)

• NYS: 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 4.3, 4.5 5.2, 6.6, 7.1, 7.2

• US Math: 4.1, 4.2, 5.1, 5.2, 5.3

• US Tech: 2.2, 3.3

• US Sci: 1.1, 1.2, 2.2

3. Resources

• School Bus and Permission Slips or whatever is needed

• Data Collection Sheet for recording data

• Compression Machine in appropriate concrete testing facility

• Safety Glasses

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• Concrete cylinders prepared earlier in class

• Have students bring their notebook and a writing utensil

• If no trip is planned, video of testing procedure and sample broken cylinders

• Data table, for recording data

4. Instruction Plan

NOTE: Need to organize transportation for the students with the school and the children's parents well before this lesson.

NOTE: Need to make sure that bringing the students to Clarkson does not interfere with Clarkson classes or research. In order to ensure availability, contact appropriate personnel in CE department well before the scheduled lesson.

Don’t forget to collect homework from previous day!

Once the students have been transported to Clarkson University they will then be shown how to operate the compression machine. They will take turns actually placing the cylinders in place and operating the machine. Students will also learn how to read the dial to determine how much load it took to break the cylinder and all of the students will be required to record the values in their notebooks or on their data sheets. Before they leave it is important to have the students measure the diameter of their cylinders to calculate area.

Make sure students are wearing appropriate personal protection equipment (safety glasses, hard hat) as they observe the cylinder testing procedure!

To operate the Tinius Olsen Testing compression test machine:

• Remove concrete cylinders from molds using compressed air stream (poke small hole in bottom of each cylinder, force air through hole to release the concrete).

• Weigh the cylinder before testing if you want to determine density.

• Clean any rough edges off of the specimens.

• Place neoprene caps on both ends and place the specimen in the compression machine.

• Adjust the load rate so that it is appropriate for small cylinders (for small cylinders, the needle goes slower than the dots).

• Load the specimen until failure – cylinder starts to crack and needle won’t go higher. Note – pieces of concrete could go flying. Safety glasses, a plywood screen and safe distance are all required.

• The load at failure (lbs) divided by the cross sectional area of the specimen (in2) gives the compressive strength in psi.

If no trip is planned – video tape the crushing of several cylinders and bring to class , bring broken cylinders, and data to class. Welcome students, show broken cylinders and ask if

93

anyone knows what happened. Explain the process to students, show video (about 8 min long)

Distribute data record sheet. Have students measure diameter, calculate area. If possible, perform the analysis using computers (excel) – enter in diameter, calculate area, then convert all loads to stress, psi – see next day’s lesson plan.

Proceed to data analysis (graphing), day 9. Extra time will probably be available, use this to show interesting slides of concrete breaking under different types of forces – there are 2 PowerPoint files available, concrete.ppt and concrete under force.ppt.

Be careful using PowerPoint in the classroom – remember to focus on showing the

pictures and diagrams, not slides with words!!

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Data Record Sheet – Concrete Testing

Date: ___________________

Diameter of cylinders (in) _____________; Area of cylinder (area = π*d2)__________ in2

Aggregates Cylinder #

Fine Coarse weight (lbs)

Load at

failure (lb)

Compressive

Strength

(psi)

95

Example output from testing of large cylinders

Cylinder # Material Tested Amount of Water Additional Sand Weight (lb) Density (lb/ft^3) Load (pounds) Compression Strength (psi) Comments

1a Recycled Plastic 5 Cups 0 Cups 6.9 118.60 8700 692.34

1b Recycled Plastic 5 0 7.12 122.38 7900 628.68 water streamed out

2a White Glass 7 0 - #VALUE! 0 0.00 didn't cure

2b White Glass 7 0 - #VALUE! 0 0.00 didn't cure

3a Green Glass 5 2 8.1 139.23 10800 859.46

3b Green Glass 5 2 8.05 138.37 9900 787.84

4a Waste Sand 3 0 8 137.51 26000 2069.08

4b Waste Sand 3 0 7.97 136.99 25000 1989.50

5a Shredded Rubber 5 1 6.26 107.60 2800 222.82

5b Shredded Rubber 5 1 6.35 109.15 2500 198.95

6a Paper 5 1 6.65 114.31 3100 246.70

6b Paper 5 1 6.63 113.96 2700 214.87

7 Broken Glass 2 0 7.5 128.92 10300 819.67

8a Wood Chips 6 0 5.95 102.27 2500 198.95

8b Wood Chips 6 0 6.1 104.85 2400 190.99

9a Gypsum 6 0 6.12 105.20 3200 254.66

9b Gypsum 6 0 5.85 `` 8400 668.47

10 Shredded PVC 4.5 0 6.9 118.60 8200 652.55

11a Completely Random 4 0.25 6.6 113.45 3500 278.53

11b Gyp, PVC, W&G Glass 4 0.50 6.00 103.13 4700 374.03

12a Rubber, Recycled Plastic 6.5 0 4.6 79.07 2600 206.91

12b Rubber, Recycled Plastic 6.5 0 4.65 79.93 2700 214.87

13a Normal - Sand & Stone 5 0 7.95 136.65 15500 1233.49

13b Normal - Sand & Stone 5 0 7.1 122.04 15800 1257.36

14 Random Extra ? ? 7.1 122.04 6000 477.48

Ingredients (for two cylinders) = (4.5 Cups Cement) + (10 Cups Coarse Aggregate) + (9 Cups Fine Aggregate) + (Amount of Water as Seen in Table)

Note: We used cement that is over a year old.

Note: Additional sand was added in a few samples because too much water was added so the mixture had to be adjusted.

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Lesson 9 – Evaluating results


This lesson will teach students to recognize how data can be interpreted using diagrams and graphs. After plotting their data on a bar graph, students will be able to select the strongest waste aggregate.

Raw data from the compression tests (load) will be used to calculate and plot stress for each of the aggregates. The graphical format – typically a bar graph since our independent data is categorical not quantitative – will help us identify the strongest concrete mix. The teacher should have a spreadsheet file prepared for each group of students that contains the raw data from the compression testing procedures.

Bar Graph: A diagram showing a system of connections or interrelations for data that has numerical dependent variable and categorical independent variable.


• Students will be able to choose a bar graph as a suitable type of plot for illustrating data that has numerical dependent variable and categorical independent variable.

• Students will be able to use MS Excel to do a simple calculation (compressive strength, stress, from load).

• Students will be able to use MS Excel to generate a bar graph that illustrates the compressive strength results from concrete testing.

Standards (days 5, 8 and 9 combined)

• NYS: 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 4.3, 4.5 5.2, 6.6, 7.1, 7.2

• US Math: 4.1, 4.2, 5.1, 5.2, 5.3

• US Tech: 2.2, 3.3

• US Sci: 1.1, 1.2, 2.2

3. Resources

• All students should receive a copy of the completed data record sheet from testing day (may or may not have calculated stress)

• a few of the broken cylinders for examples

• Computer files or CD’s with a spreadsheet containing all data from testing at Clarkson (one per group of students). Ideally, these spreadsheets will already be open on the computers they will use to save time. (See data sheet above – have one spreadsheet for fine and one for coarse aggregates. Leave an empty column next to the name of the aggregate for calculating the strength, if students will do this step. Otherwise, have this already filled in.)

• Instructions for making a chart with Excel (attached)

• Computer projector would be great to show on screen what students need to do

• Access to computer lab

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4. Instruction plan

1. (5 min) Have students who participated in testing describe what they did and saw. Pictures (video) of testing facility and broken cylinders would be good to show. (note,

if students have not all participated in crushing cylinders, this lesson is combined

with the previous)

2. (10 min) Remind students of where we are in our overall problem solving (choose the best solution – in this case – the best aggregate). But at the same time, we are in a smaller problem solving loop – determine the strength of concrete with waste aggregates – we did many of the steps, now need to evaluate results. Important – strength is only one criterion for a suitable aggregate. The strongest may not be the ideal choice, as we’ll see tomorrow!

3. Ask students – we collected lots of data (see if they can recognize that we collected data on “compressive strength” of the different concrete mixtures). How can we compare the data so we can use it to help us make a decision? See if anyone can come up with the idea of making a graph (probably likely if students did the graphing activity with the pasta lab).

a. Introduce students to a bar plot by drawing one on the board. Initially leave out the actual values of each aggregate. Discuss when a bar graph is an appropriate type of plot to use.

b. (could do this next step with probing questions) Describe that the strength will lie on the y-axis (dependent, numerical data) and the type of aggregate will lie on the x-axis (independent, categorical data). **Strength (y) depends on type (x).** Draw a few bars as examples. Identify other aspects of graphs that are critical (title, axis labels, units etc).

c. Look at data record sheet – no strength (stress) included! Review how to calculate strength from load and cross sectional area. Indicate that we will let the computer do this for us, we do not need to do it individually for each sample.

d. If possible, project the excel spreadsheet onto the screen and introduce the students to the data it contains, the formulas they will have to enter to calculate strength, and the icon for plots. Use instruction sheet provided.

3. (20 min) Split students into groups of two and move to the computers. Each group will be assigned one plot to generate (either fine aggregate or coarse aggregate). Wander around room and help students with their work. All students should be expected to generate and print their graph and calculations. Work will have to be completed as HW if not finished in class.

4. If students finish, bring class together with final plots. Discuss which aggregates were strongest – were they surprised? What do we do now – why did we do this? (to help decide which aggregate to use) Can we decide now? (no, we need to take into account other criteria – we’ll do this tomorrow)

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Analyzing Strength Data using Excel

o Log on to computer o Go to Start Menu

� Programs

� Excel To enter data:

o Type in the aggregate material in one column o Type in the load (in pounds) in another column o Type in diameter in a third column o The next column will be for the cross-sectional area. In the top cell of the next column,

type in the formula for area, using the cell where the diameter is entered as “d”: “=π*d2/4”. Copy this cell down the entire column (area should be the same for all entries)

o Enter strength in the next column – strength = load/diameter (psi). Enter the formula in the top cell and copy all the way down the column.

To make plot:

o Highlight the strength column (psi) by holding down left mouse over all the values o Hold down the control button and highlight the aggregate material strength column o Go to Insert Chart

� bar

� NEXT � NEXT

o Type in Chart Title Name, X axis name, and Y axis name � NEXT

o Save chart as a New Sheet (give title)

� FINISH

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Lesson 10 – Weighted Objectives Table and Optimum Mix Sheet


Engineers often have to consider many different criteria when making choices about materials or other design variables. The criteria should include technical effectiveness of a material or process, cost, and social and environmental consequences. Taken individually, these criteria could lead to very different choices. A weighted objectives analysis is one way to use a rational basis for incorporating the multiple criteria into the decision.

For our particular problem, students should incorporate not only the strength of the concrete, but also aesthetics and the environmental benefits of using a particular waste as an aggregate. For example, a material that is otherwise not conveniently recyclable might have more positive impacts as a waste aggregate than a material that already has a recycle use. The strength of the mix needs to be put in perspective – how strong does the concrete have to be for the desired application? It may be that the weaker mix is still strong enough, and excels in other criteria, making it the optimum choice.

Students will learn how to create and analyze a weighted objectives table to make an objective decision regarding the best waste aggregate for their concrete mix.


• Students will be able to define a list of criteria that are important to consider when analyzing their aggregate choices.

• Students will be able to analyze data and will be able to determine the most suitable concrete aggregate.

• Students will be able to identify needs and opportunities for technical solutions from an investigation of situations of social interest.

Standards:

• NYS: 1.1, 1.2, 1.3, 5.1, 6.6, 7.1

• US Math: 5.3

• US Tech: 1.3, 2.1, 2.2, 3.2, 4.3

3. Resources

• Teacher’s guide – Weighted Objectives Table Example

• Weighted Objectives Table Worksheet

• Samples of broken cylinders for students to observe, if desired

4. Instruction plan

1. Introduction and brainstorm (5-8 min)

Remind students about the results of their strength testing – which aggregates are strongest? Ask them – do we choose these? Is strength the only important factor? No, we need to think about other criteria as well.

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Brainstorm other criteria as a class. Good criteria to use are aesthetics (does it look nice?), texture (smooth/rough), feel (crumbly?), availability (how much of the aggregate material do we have on hand?), severity of the waste (is the aggregate material “truly” a waste? Or does it already have other possible uses?). They may come up with additional ideas, write them all down. Don’t erase!

2. Weighted Objectives Table Lesson (10 min)

How do we make a decision that takes into account all these criteria that are important to us?

Introduce students to what a weighted objectives table is – a tool for multiple criteria decision making.

Use an example of something the students are interested in. For example, you can use superheroes.

1. Draw a blank weighted objectives table on the board (or overhead).

2. Ask the students what superhero they think is best – write answers on board in a list. Let them pick four or five of their favorites. Tell them we will use the weighted objectives table to mathematically “prove” who really is the greatest.

3. List attributes of a great superhero, for example strength, fighting abilities, weaknesses, and attractiveness of tights. As a class, decide which attributes are the most important – choose 5 attributes, then rank them 1 through 5, with 5 being most important, 1 being least important.

4. Using an overhead or the board, go through the weighted objectives table with the class in determining the best superhero.

� Write superhero names in appropriate places.

� Write criteria (attributes) in appropriate places.

� Assign weights to the different attributes. The weights they apply to the various attributes could sum to 1 (or you could use % and have them add to 100), although this is not critical. Give higher weights to more important attributes.

� Score each attribute for each superhero. The scores for each attribute should be on a scale from 1-10 (10 being best, 1 being worst).

� Calculate the rank for each attribute for each superhero (rank = score x weight).

� Sum the ranks for each superhero – the highest rank is the best choice.

Ask the students if they think they can use this analysis to find the best aggregates for their project.

3. Use the weighted objectives table to determine the most suitable waste aggregate (20 min). This can be done in small groups or as a whole class activity – if done in groups, make sure all groups use the same list of criteria, then come together at the end of class to summarize all scores and get a final (can make a big chart on board and have each group write in their numbers, then have someone add up)

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NOTE: depending on how the recipes were arranged, it may be best to have half the class

look at fine aggregates and the other half look at coarse aggregates. There will be 2 results –

one for the best fine waste aggregate, and another for the best coarse waste aggregate.

1. Revisit the list of criteria from the brainstorm. Guide the students to reduce the list to 4 or 5 items that are most important – from the teacher’s perspective, it’s very important to include “availability” as an important criteria, to make sure that we have enough of the chosen aggregate!

2. Distribute blank weighted objectives tables – either to individuals or in groups. .

3. First have students list the aggregate types across the top, and the criteria down the left side. Then they should weight the criteria, in order of importance (higher weight number means more important). Again, the numbers here are arbitrary, as long as the higher numbers are for the more important criteria.

4. Students should then evaluate each aggregate material for each criterion. Students should use the graphs they generated from their test cylinder data, in addition to what they know about the different aggregates, to help them determine rankings for some different attributes (strength, aesthetics). They may need help for some criteria (e.g., availability, severity of the waste). Samples of broken cylinders may also be helpful.

5. Multiply weight x rank for each aggregate/criteria combination, enter the value in each space provided. Sum the ranks for each aggregate, to get a final score.

6. Teachers should visit groups to answer questions.

7. If done in small groups, students should enter the scores for each aggregate onto a chart on the board. These should be added together, to determine the final outcome. The result should be the best overall aggregate to use.

8. Wrap up – return to problem solving method – indicate where we are in overall problem solving – we just chose the best aggregate! Verify as a class that these materials are best suited for our design project (and also make sure we have enough of them!). What’s next? – we will implement our solution by building a product with concrete and solid waste.

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Weighted Objectives Table - Example

Fine Aggregates Coarse Aggregate

Re

cy

cle

d P

las

tic

Wh

ite

Gla

ss

Gre

en

Gla

ss

Wa

ste

Sa

nd

Re

gu

lar

Sa

nd

Sh

red

de

d R

ub

be

r

Sh

red

de

d P

VC

Bro

ke

n G

las

s

Gy

ps

um

Wo

od

Ch

ips

Pa

pe

r

Pe

a S

ton

e

Strength (.25) 9 2.25 4 1 5 1.25 8 2 7 1.75 7 1.75 5 1.25 10 2.5 4 1 2 0.5 2 0.5 7 1.75

Weight (.20) 5 1 7 1.4 6 1.2 5 1 4 0.8 9 1.8 10 2 5 1 10 2 10 2 10 2 9 1.8

Appearance (.20) 9 1.8 10 2 9 1.8 10 2 9 1.8 9 1.8 9 1.8 8 1.6 7 1.4 4 0.8 3 0.6 9 1.8

Cost (.25) 10 2.5 7 1.75 7 1.75 10 2.5 10 2.5

10 2.5 10 2.5 5

1.25 10 2.5 10 2.5 10 2.5 10 2.5

Availability (.10) 5 0.5 9 0.9 1 0.1 8 0.8 2 0.2 9 0.9 9 0.9 10 1 9 0.9 10 1 10 1 9 0.9

Total 8.05 7.05

6.1

8.3

7.05

8.75

8.45

7.35

7.8

6.8

6.6

8.75

For this example (arbitrary values in table): Criteria:

1. Strength: This is the strength of the concrete cylinder, greater strength = higher score 2. Weight: This is the weight of the concrete cylinder, less weight = higher score 3. Appearance: This is the appearance of the cured concrete, more attractive = higher score 4. Cost: This rates the relative expense of the aggregate – did you have to pay for it? Did it

cost a lot? 5. Other values to consider: Availability – is it easy to get the quantity you need? Landfill

potential – will it end up in the trash if it’s not used as an aggregate? Other values?

Each criterion is weighted a certain amount, depending on its importance relative to the others listed. For example Strength is weighted 0.30 as can be seen in the table above. These weightings are chosen based on the engineer’s decision regarding the most important criterion.

Each aggregate is then rated on a scale from 1 to 10, where 10 is the highest, for each criterion. These numbers are entered in the grid, where the criterion and the aggregate intersect (example, shredded PVS is free so is given a 10 in that category).

To find the total score for each aggregate, the score for each criterion is multiplied by the weight factor, and these are then added together for the aggregate. (Note that in the blank student table an extra column is provided for this stage of calculations.) For Recycled plastic…

5.8)10)(30(.)9)(20(.)5)(20(.)9)(30(. =+++=Total

The highest score within the fine aggregates, becomes the fine aggregate of choice. The highest score within the coarse aggregates, becomes the coarse aggregate of choice.

Example: The best fine aggregate is Recycled plastic with a score of 8.5.

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The best coarse aggregate is Shredded Rubber with a score of 8.7. Therefore when the concrete is mixed, Recycled Plastic and Shredded PVC are the aggregates that should be used.

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Weighted objectives Table

Your Name:

Teammates:

ATTRIBUTES

WEIGHT

TOTAL

Indicate COARSE or FINE aggregates:______________________

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Checklist of Student Progress for Weighted Objectives Table Student: _______________________

Learning Goals Checklist Observation

Identify important criteria

• List criteria

• Make decisions about which ones to pick

• Some sort of logical elimination skill

Developing the table

• Able to label the table appropriately

• Able to rank criteria

• Able to compute weights for each criteria

Applying understandings

• Able assign different values to the criteria for each energy system

• Able to calculate score

• Analyze all alternatives and deduce from the table which is the best system based on all chosen criteria

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Lesson 11 – Value of Product


Marketing products is a critical step in getting good ideas and products from the concept and manufacturing stage to the actual purchase and use of a product. Effective marketing requires good communication skills, an understanding of the value of the product, and an understanding of consumer choices. Market research is typically done alongside product development, to ensure that the concept and effort are economically viable.

For problems such as the one we are solving in this unit, consideration of the value of the product becomes quite complex. Economic value can be calculated, based on the monetary value of the goods produced. (“Goods” refers to concrete products.) There is also economic value associated with reductions in solid waste generation, saved landfill space, and reduced costs incurred by using recycled, rather than virgin, materials as inputs to production. However, these problem solutions also have aesthetic and social values that cannot be measured as easily as a monetary savings. These products offer environmental benefits – by using one of our products, a consumer is demonstrating that he/she is taking a step toward “saving the environment.” Some consumers are willing to actually pay more money for such products than for traditional, less “environmentally friendly” products. The extent to which this benefit is valued, though, will vary from consumer to consumer.

An understanding of the complexities of the benefits is required to adequately market these products.

All products must be marketed in order to be successful. Market research makes it possible for companies to determine the level of interest that the public has for particular products or services and the amount of money they would be willing to pay. This helps companies to meet the needs and wants of the consumer.

A marketing plan is created to guide the development and sale of marketable goods or services. Decisions need to be made concerning product distribution, pricing, and advertising. Advertisement design and the choice of advertising media (radio, television, newspaper, billboards) often depend on the target market for the specific product. (For example, children’s toys are often advertised in television commercials that are aired during children’s programming.)

This lesson will help to show that a valuable product has been made from our solid waste. Concrete products are valuable commodities with many benefits and few associated costs. There are both economic benefits, which can be assigned a dollar value, and non-monetary benefits such as aesthetics, environmental friendliness, or social choice.

The benefit of a product may differ between the point of view of the producer and the consumer. The producer values ease of production and high profit. The product won’t be manufactured if it is not expected to generate sufficient profit for the producer. The consumer values the cost of the product relative to its intended function, durability and, sometimes, the environmental impacts associated with the product.

Concrete products made with solid waste aggregates can be cheaper to produce, compared to traditional concrete, if there is a nearby source of suitable waste aggregates. The use of these waste materials reduces the producer’s cost of buying sand and gravel. In addition to marketing

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the functional qualities of our concrete product (e.g., patio building materials), the producer can exploit the environmental benefits of the product to reach a broader market share. The environmental benefits include reducing waste sent to the landfill and the associated loss of quality materials, as well as reducing the need to mine more sand and gravel from our land.


• Students will be able to define marketing.

• Students shall be able to assess the benefits of a commodity.

Standards:

• NYS: 3.3, 5.6, 7.1

• US Tech: 2.1, 2.2, 2.3, 4.3

• US Math: 1.3, 5.1

3. Resources

• Teacher resource on marketing

• Marketing factsheet handout

• Student worksheets – Value of our Product – Value to the Producer, Value to the Consumer

• Newspaper or magazine advertisements, cut out for distribution

• Appropriate grading rubric for student-created advertisement (poster, oral presentation, etc.)

4. Instruction plan

1. (5 minutes) Introduction.

a. Revisit the problem solving method. We have implemented a solution to our problem. Are we done? What do we need to do now? Assess our solution to see if it works – we can’t do this now, because we need to let our molds cure before we can see our finished product.

b.When someone decides to make a product, what – besides technical aspects students identified in their weighted objectives table (strength, color, etc.) – makes the product successful? Usually, in today’s world, we want the product to be marketable.

2. (15 minutes) Introduction to Marketing.

a. What is marketing? Define for students and hand out marketing fact sheet. Go over terms.

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b.What is a marketing plan? Using a sample product, such as a car, talk about the different ways that the product can be marketed (advertised) – tv, radio, billboard, poster, newspaper, magazine.

c. Have students get out the advertisements they brought in, or distribute some to groups of students. Have students answer the following questions about their advertisement:

a. How would you describe the product?

b. What are the unique features of this product that the advertisement is trying to exploit?

c. What advertising techniques are utilized?

d. How does the advertisement capture its audience?

e. Does this ad make you want to purchase the product? Why or why not?

3. (15 minutes) The value of our product.

a. Remind the students of our initial problem statement: How can we make useful

products that reuse or recycle components from our community’s solid waste

stream?

b.Brainstorm – what makes our product “valuable?” Consider the benefits from using our product as a replacement for a currently used consumer product, or as a means of reducing environmental degradation from solid waste. (Refer to Teacher Notes for discussion ideas.)

c. Introduce the idea of “Value to the Consumer” versus the “value to the producer.” See the “Teacher Notes” for suggested topics and statistics.

d.Value to the Producer: Have students do some quantitative analysis of the cost of making their product. Distribute “value of our products – value to the producer” worksheet

i. Calculate “net income” (sale cost minus cost of production) for concrete product (use worksheet provided).

ii. Optional -- Calculate savings associated with reduced solid waste disposal costs. (estimate volume of solid waste per stone, use cost of waste disposal – see teacher notes)

e. Optional: assign the “Value of our Product – value to the consumer” student worksheet as homework

5. (next day, or remainder of time) Value to Consumer: Assign students to create an

advertisement for their product.

a. If students have not already done so, have them complete the worksheet: Value of our Product – Value to Consumer.

b. They should use any media available (poster, computer slide show, could do a radio or advertisement)

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c. Students should use the results from their brainstorm and worksheets about what makes the product valuable (think about the value to the consumer)

d. Don’t forget to include the price!

e. Students should present their advertisements to the rest of the class.

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Understanding the Value of Our Product

Teacher Notes

Economic accounting can be included among the benefits or added value of our products. Some useful cost information is included here if you wish to include this as a quantitative assessment.

Value to the producer/manufacturer

The manufacturer generally wants to make an economic profit. How do we know if we have made a profit?

sale price of the product – all expenses required to build the product = profit

Example – concrete stepping stones:

sale price ~$3.50 per 12” octagon stepping stone

what are our expenses?

cement $8/bag of cement; 30 stones / bag 0.27

waste aggregate (FREE!!)

mold $4.10 uses per mold 0.40

labor $7/hour; 10 stones per hour 0.70

Total: $1.37 / stone

Profit: $2.13 / stone

(note – a good extension for math class – calculate these expenses per block rather than giving them the answers)

So, if our product is salable, we could make a good profit. Therefore, this product has value for the manufacturer. Savings from not disposing the solid waste in the landfill:

In northern NY the typical cost for municipal solid waste disposal to the consumer is equivalent to the cost of one clear 13-gallon trash bag plus the cost of one required “trash sticker” per bag (note that this does not include the additional taxes incurred for municipal waste handling). 1 13 gallon bag = 0.20 1 trash sticker = 0.80 total disposal for 13 gallons = $1.00 13 gallons = 208 cups One stepping stone uses approximately 5 cups of waste aggregate. So, if it costs approximately $1.00 to dispose of 208 cups of waste, the savings per stepping stone is calculated as:

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cupscups

x

208

00.1$

5

$= x = 2.4 cents (minor, but worth noting!)

Value to the consumer

The value to the consumer can vary widely depending on his/her own priorities. For example – one person might want to buy these stepping stones because they might be cheaper (due to free aggregate), whereas someone else might find value in the “green” nature of this product (less waste to the landfill) and might even be willing to pay more because of that.

Why are our products valuable to the consumer?

Example – Concrete stepping stones:

• Economic value associated with reduced cost of these products (lower production costs should be reflected in lower sales costs).

• Environmentally friendly product – many consumers are concerned with buying products that have low impact on the environment. Our product turns a waste material into a valuable commodity, and reduces the rate at which our landfills are filled.

• They are good looking!

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Marketing Fact Sheet

Marketing: all activities utilized to sell a product. Two major types of markets: industrial and consumer Marketing plan: used to predict what products will sell and the

quantities that can be expected to sell Market research: all activities used to determine what people want and

how much they’ll spend for it Types of market research: interview, test marketing, opinion polls, etc. Advertising: informs or persuades a consumer to buy a product Target market: group of people most likely to want a product Types of advertising: television commercials, radio spots, billboards,

samples, and brochures Types of sales: direct sales, wholesale, and retail Distribution: process of moving goods from the producer to the

consumer

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Value to the Consumer NAME: _____________________ Answer the following questions about the concrete product that you produced in technology class. 1. Name of your product:

__________________________________________________________

2. Explain why you decided to produce this product: ____________________________________________

_____________________________________________________________________________

3. What attributes of this product do you think make it most valuable to the person making the product? ___________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

4. What attributes of this product do you think make it most valuable to the person buying the product?

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

5. Are there any attributes that make this an environmentally friendly product? _____________

______________________________________________________________________________

______________________________________________________________________________

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Value to the Producer

Name: _________________________________________ Use the information in the table to answer the questions below. Cost of Producing 12-inch Concrete Garden Stones

Item Cost of one unit

Number of stones per unit

Cement $8.00/bag 30

Waste aggregate free n/a

molds $4.00 10

Labor $7.00 10

1. What is the total cost of producing 1 garden stone? - Cement: - Molds: - Labor: 2. If one garden stone sells for $3.50, what is the profit per stone?

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Lesson 12 – Prototype production


Concrete can be formed into a valuable product by casting it in a mold. Students will pour concrete into small molds to make a valuable product.

Concrete products are made by pouring the concrete in a suitable mold of the desired shape. The surface qualities of the final product can be modified based on the choice of the material that the mold is made from (e.g., plastic provides a shiny and smooth surface).

In class, the students can consider the products they make to be prototypes of a final product. In the engineering design process, a prototype is made to test the concept and manufacturability of a particular product. Based on the success of the prototype, a producer or manufacturer might alter the design or the production process.


• Students will create a product out of concrete.

• Students will demonstrate appropriate tool use.

• Students will demonstrate successful teamwork to accomplish their goals.

Standards

• NYS: 5.2, 5.6

3. Resources

• Teacher resource: concrete product manufacture and testing

• Concrete forms

• Cement

• Aggregates

• Buckets

• Trowels

• Measuring cups

• oil for mold release

• safety equipment (glasses, gloves, masks)

• LOTS of paper towels!

4. Instruction plan

Build a product using forms either purchased or built by the instructor. See teacher resource for ideas on recipes and products.

Example plan for concrete stepping stones:

- Review concrete safety rules with class before beginning!

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- Conduct class similar to the cylinder making day – all instruction and most of the material distribution should happen in the classroom before students leave their seats; stations should be set up around the work area, with teachers to assist; use a designated measuring cup for each station (and the water!) to avoid contamination of the materials.

- Divide class into pairs, provide each pair with a mold.

- Have each student mix enough concrete for half of the mold (see teacher guide for recipe).

- Have students oil their molds very thoroughly (either distribute oil or have a station set up with oil).

- Set stations up around the room with concrete ingredients. Provide each student with a bucket for mixing their concrete, and have them circulate through the stations to collect ingredients (dry first, then mix, then water). Do this in a similar way that the concrete cylinders were done.

- When the concrete is mixed, have each pair fill their molds. (if doing stepping stones, lightly tap the mold onto the tabletop to dislodge air bubbles)

- Set molds in designated classroom area to cure.

- Clean up!

Wrap up (or have them think about for homework) Ask: Now that you have made your prototype, what specifications or criteria should you consider in order to determine if we’ve met the requirements of the problem statement (Make a useful product…)? (Consider strength, aesthetics, function etc.) Do you think your product will be successful? What might you change next time?

For next time: ask students to bring in an advertisement, for anything at all (e.g., magazine ad for car, radio, cell phone…)

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Lesson 13 – Wrap-up / Final assessment

Assess students using the concrete exam Later, when concrete prototypes have cured, complete the evaluation sheet

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Name____________________________________

Period____________ Project___________________________________ Date______________

Evaluation For Concrete Project

1. Appearance of this project (FORM) is this project aesthetically pleasing? POOR NICE VERY NICE 1 2 3 4 5 6 7 8 9 10 2. Creative (Boring, or Interesting) 1 2 3 4 5 6 7 8 9 10 3. Concrete mixture (Concrete has proper mixture, is durable enough to complete desired task) 1 2 3 4 5 6 7 8 9 10 4. Accuracy (Follows plans) 1 2 3 4 5 6 7 8 9 10 5. Craftsmanship (Project is neat and well built, square, proper use of fasteners) (or flimsy and weak) 1 2 3 4 5 6 7 8 9 10 6. Ergonomics (project takes into consideration the human factors engineering, It is built so that it will

be comfortable, and easy for the user to operate) 1 2 3 4 5 6 7 8 9 10 7. Group safety (My group cleans up after we work and takes into consideration others safety) 1 2 3 4 5 6 7 8 9 10 8. Safe and proper use of machines and tools 1 2 3 4 5 6 7 8 9 10 9. Proper use of materials (Project uses materials efficiently, does not waste or misuse wood, plastic,

metal, or concrete) 1 2 3 4 5 6 7 8 9 10 10. Function (Project operates well, completes what it was intended to do) 1 2 3 4 5 6 7 8 9 10

Total Points = preliminary Grade______________ Choose to redo project, and re-evaluate Evaluation date___________________

Total points after re-evaluation FINAL GRADE______________

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Name_______________________________ Date_______________

Eighth Grade Technology Quiz: Concrete Unit

1) (8 points) Name the four ingredients that are used to make concrete. 1)___________________ 2)___________________ 3)___________________ 4)___________________

2) (8 points) Name four waste materials that could be used as aggregate in concrete?

1)___________________ 2)___________________ 3)___________________ 4)___________________

3) (5 points) Why would we want to use waste aggregate and not regular stone in concrete?

__________________________________________________________________ __________________________________________________________________

4) (4 points) Circle the word that correctly fills in the blank:

As concrete cures, it should be kept _____________.

Dry wet


Concrete can withstand high ________________ forces.

compression tension

6) (4 points) What safety concerns would you consider when making concrete?

120

7) (8 points) Is the rope in the following diagram in tension or compression?

______________________ Ceiling Rope

Weight

8) (8 points) A set of concrete stairs needs to support an elephant as it walks into and out of its cage. The concrete must have a compressive strength of at least 10,000 pounds per square inch (psi) to hold the weight of the elephant. The circus people have to move these steps every time they travel, so they want these steps to be as lightweight as possible. According to the data in the chart below, what should the circus people use as aggregate in the concrete steps? Circle your answer.

Stone Rubber Glass Paper Wood Why did you choose this aggregate? _____________________________________________________________________

Aggregate Weight (pounds) Compressive strength (psi)

Stone 5.0 20,000

Rubber 2.5 11,000

Glass 3.0 12,000

Paper 1.5 8,000

Wood 2.0 9,000

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9) A concrete test cylinder with a 1-inch radius is tested and can withstand 2,000 pounds of compressive force. The area of a cylinder is equal to π*r^2, where r is the radius. The engineer who is testing the cylinders wants to get the results in terms of stress.

a. (5 points)What units are used to show stress? b. (8 points) Calculate the stress, knowing the force and the area. Show your work!

10) Imagine that you are asked to build a concrete storage building that is 8 feet high, 8 feet

long and 10 feet wide, and you need to use some type of waste aggregate in your concrete mix:

A. (6 pts) List 2 criteria that you might consider when deciding which waste materials to use.

1. 2.

B. (6 pts) Name 2 waste materials you might you focus on, and describe what makes each a good choice.

1. Material: Why? 2. Material: Why?

122

C. (6 pts) Name 2 positive environmental impacts of using these materials.

1. 2.

D. (4 pts) Before you begin this project, what needs to be considered to avoid long term problems?

123

Name_______KEY___________________________ Date_______________

Eighth Grade Technology Quiz: Concrete Unit

1) (8 points) Name the four ingredients that are used to make concrete. 1 Coarse Aggregate________________ 2)____Fine Aggregate_______________ 3)____Cement_______________ 4)____Water_______________

2) (8 points) Name four waste materials that could be used as aggregate in concrete?

1)_______shredded rubber 2)______ground glass_ 3)______shredded plastic 4)_______wood chips (many suitable answers – do not accept sand or gravel)

3) (5 points) Why would we want to use waste aggregate and not regular stone in concrete?

____Lower price, saves space in the landfill, may offer better characteristics in the finished product (e.g., rubber makes the concrete “softer”, plastic makes it lighter, glass makes it reflective)


As concrete cures, it should be kept _____________.

Dry wet


Concrete can withstand high ________________ forces.

compression tension

124

6) (8 points) Is the rope in the following diagram in tension or compression?

__Tension____________________ Ceiling Rope

Weight

7) (8 points) A set of concrete stairs needs to support an elephant as it walks into and out of its cage. The concrete must have a compressive strength of at least 10,000 pounds per square inch (psi) to hold the weight of the elephant. The circus people have to move these steps every time they travel, so they want these steps to be as lightweight as possible. According to the data in the chart below, what should the circus people use as aggregate in the concrete steps? Circle your answer.

Stone Rubber Glass Paper Wood Why did you choose this aggregate? _______________it’s strong enough, but lighter than the others.________________

8) A 2-inch diameter concrete test cylinder is tested and can withstand 2,000 pounds of compressive force. The area of a cylinder is equal to π*d2/4, where d is the diameter. The engineer who is testing the cylinders wants to get the results in terms of stress.

c. (5 points)What units are used to show stress? Pounds per square inch, psi d. (8 points) Calculate the stress, knowing the force and the area. Show your work!

Area = 3.14 in2, so stress = 2,000/3.14 = 636.6 psi

Aggregate Weight (pounds) Compressive strength (psi)

Stone 5.0 20,000

Rubber 2.5 11,000

Glass 3.0 12,000

Paper 1.5 8,000

Wood 2.0 9,000

125

9) Imagine that you are asked to build a concrete storage building that is 8 feet high, 8 feet long and 10 feet wide, and you need to use some type of waste aggregate in your concrete mix:

• (6 pts) List 2 criteria that you might consider when deciding which waste materials to use.

Strength, appearance, texture, availability, severity of waste, density…

• (6 pts) Name 2 waste materials you might you focus on, and describe what makes each a good choice.

1. Material: Why? Glass – heavy, reflective, strong, rough texture Styrofoam – lightweight, cheap Rubber – resistant to corrosion, cheap Pvc – strong, cheap, not bad looking

• (4 pts) What safety concerns would you consider and why? Avoid skin contact, eye contact, don’t breath in dust – health hazards. Be careful when

building! Dangers associated with heavy lifting and power tools.

• (6 pts)Name 2 positive environmental impacts of using these materials.

1. removes material from landfill 2. preserves natural resources

• (4 pts) What concerns would you have about proceeding with the project? Is the material strong enough? Will it last for the lifetime of my building? Will it hold together in the weather? Can I get enough of it? Will it look OK?

design & marketing of concrete products curriculumcu.clarkson.edu/highschool/k12/pdf/concrete...

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