Carolina Biological Supply Company

An Exciting 35 Years Teaching Chemistry—What I’ve Learned!

NSTA 2011San Francisco

Teaching Tips for Chemistry

Classroom strategies:

• Constant practice on difficult topics. Start each new class with a review of topics from previous class, e.g., Challenging Problem of the Day

• Exciting demonstrations with open-ended questions

• Mnemonic devices and problem short-cuts (see packet)

• PowerPoint® lecture material with animations or lab analysis problems stored on Internet

• Computer simulations and technology

• Learning groups and study sessions

• Review outside of the classroom, e.g., Chem Jams

Teaching Tips for Chemistry (continued)

• Research projects on difficult units such as acids and bases

• Finish the material in the textbook, leaving at least 1 week for review

• Provide links to chemistry Web sites; hand out old exams throughout the course

• Students can make presentations—descriptive chemistry section.

• Chemistry hot-line to instructor

• Grading of homework (very important)

Motivational Tools

• Academic Contests, such as Chemistry Field Day

• Online difficult question of the day

• Celebration of Mole Day—making moles

Teaching Techniques

Use a clever idea or gimmick!

When teaching the scientific method:

• Use mystery stories to explain how a scientist solves problems.

• Case of the power failure—see handout.

Mnemonic Devices and Shortcuts

Ideas for simplifying chemical calculations

Finding the limiting reagent:

a. To find the limiting reagent, use this easy method:

1. First, find the moles of each reactant

2. Divide the moles of each reactant by its coefficient. The smallest number obtained is the limiting reagent!

WORKS EVERY TIME!

Another Shortcut

Electrolysis Problem

Easy way to find the number of grams of a certain metal electroplated during an electrolysis reaction

Equation needed: #g = amps x time(sec) x eq. weight96,500

eq. weight = atomic or molar mass/number of e- transferred

Mnemonic Devices

Some ways to remember chemistry facts:

Cations are (pawsitive)

Metric conversions:

km ---> hm ----> dam ---->m ----> dm ----->cm----->mm

―King Henry died Monday drinking chocolate milk.‖

More Mnemonic Devices

Shapes of Molecules

Learn the first shape from each series and erase a line in the VSEPR structure every time an E appears in the formula.

Another trick—every shape that does not have an E is nonpolar except for square plane.

Classroom Demonstrations

Fire Balls on the Ceiling

This is a spectacular demonstration for the first day of school. It uses the following materials:

• Small funnel with hose attached to a gas jet

• Soap bubble solution from toy store

• Small glass dish

• Candle with paper disk to collect wax

• Matches

Classroom Demonstrations(continued)

Demonstration can lead to discussions of combustion reactions, exothermic reactions, etc.

Possible questions for demonstration:

1. What kind of reaction is this?

2. What is supplying the activation energy for the reaction?

3. Write the balanced equation for the reaction.

Pictures of Fire Balls on Ceiling

Fire Balls at Duchesne Academy

Fire Balls at Duchesne Academy

Additional Pictures

More Demonstrations

Demo #1—Equilibrium Shifts, Le Chatelier’s PrinciplePhysical equilibrium—using ammonia solution and phenolphthaleinSee instructions on handout

Demo #2—Glow-in-the-Dark QuarterDemonstration of phosphorescence

Demo #3—Cartesian Diver and Boyle’s LawDemonstration of pressure and volume effects along with supplementary inquiry labSee instructions on handout

Demo #4—Burning Tower of Terror• How does it work?• Everyone knows that hot air rises. This experiment demonstrates

that idea as well as the principles of convection currents.

Inquiry minilabs

Laboratory Program

Purpose of laboratory program:

• Reinforce lecture material already covered or means to introduce new lecture material through inquiry

• Excite students about lecture content

• Prepare for experiences in college using interface equipment

• Improve critical thinking skills—encourage student to take risks and try novel solutions

Technology in the Chemistry Classroom

Chemistry is great with the following technology:

• Excel® and spreadsheets. Graphing lab data is an excellent exercise for helping students get ready for college and seeing an accurate graph for analyzing data.

• Interfacing equipment makes some labs work like a charm. Titration curves come out looking like textbook data.

• Peer review of research projects is an excellent learning tool. Students can put their projects online.

• Equations can be solved in Excel® and data analysis is faster. More labs can be done per year.

• Simulations from the Internet.

• Information storage on Internet—Angel.

Boyle’s Law

Sample Data from Interface Equipment

Additional Graphs from Interface Equipment

Acid-Base Titration

Sample Data from Interface

Graph of Temperature

vsTime for Rate of

Evaporation

Laboratory Simulations

Quite powerful displays to stimulate student interest!

• http://hyperphysics.phy-astr.gsu.edu/HBASE/quantum/atspect3.html#c1

• http://jersey.uoregon.edu/vlab/elements/Elements.html

• http://preparatorychemistry.com/11Bishop.pdf

• http://www.quia.com/fc/65800.html

• http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/hybrv18.swf

• http://highered.mcgraw-hill.com/sites/0072396814/student_view0/animations_center.html

Laboratory Scheme for Limited Time and Money

• Keep in mind time and money as you plan your labs.

• For example, my students prepare and standardize a solution of NaOH made in a liter pop bottle. The pop bottle is then labeled with the correct molarity.

• This bottle can be used for 4 more labs and is easily stored.

• Since the molarity is already accurately known, much time is saved in future labs. Also, chemicals are not wasted.

• Can also serve as an error analysis—younger

students use bottle standardized by AP®

Chemistry students to find percentage of acetic acid in vinegar.

Lab Program

• Labs should motivate, excite, and stimulate critical thinking.

• Some samples to consider:

1. Inquiry lab on matching solutions

2. Limiting reagent with balloons

3. Reaction order and rate constant

4. Solubility rules

5. Preparation of solutions

Inquiry Lab on Matching Solutions

• Students will be given 2 sets of 5 solutions. One set will be labeled A–E and the other set will be labeled 1–5. Each set has the same 5 solutions.

• Solutions are: NaOH, HCl with pHpH, CaCl2,

Na2SO4, and NaHCO3.

• Students will try to match the solutions.

• At this point, you can also introduce net-ionic equations.

• See handout for instructions.

Participants engage in lab activity

Limiting Reagent

• This laboratory exercise uses baking soda, vinegar, and balloons.

• Very visual lab—students can immediately see the limiting reagent by the size of the balloons.

• This lab is in your packet.

Solubility Rules

• Students use a 90-well plate and react solutions of various salts.

• The brilliant colors of the precipitates can be observed to help students derive the solubility rules.

Research Project Acid-Base Chemistry

• This is a research project done during the 3rd quarter that links my Chemistry Honors class and my AP® Chemistry class.

• This excites the younger students to take AP® Chemistry and gives the older students a sense of responsibility and pride.

• For the basis of this project, AP® Chemistry students prepare a standardized solution of NaOH, which the younger students use to calculate the percentage of acetic acid in vinegar.

Honors Chemistry Research

• The solutions made by AP® Chemistry students and standardized are then used by students in Honors Chemistry for their research project.

• The data supports the fact that the bottles were standardized correctly as they also obtained values of about 5% acidity for the vinegar solution.

Outcomes of Research Project

• Many parts of this project require students to design their own experiment.

• This is a writing project for writing across the curriculum.

• Environmental issues are discussed when disposing of the bottle.

• Error analysis is accomplished through the use of a spreadsheet and collection of data from various sources.

Final Notes

• This project provides a collaborative framework for students.

• The AP® Chemistry class is excited and motivated to do well since their younger peers will use their standardized solutions.

• The bottles of NaOH are easy to store and can be used for other laboratory experiences.

• This project has a computer component, which is necessary for our laptop program.

Carolina Free Resources

Carolina offers many free resources to help support teachers.

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