Scientist think and talkLanguage of Science

* Are you hyperactive or hypoactive today?

Thinking about thinking

• What are the numbers on the bottom of the dice?

• How do you know?

What is the one thing shared by all three items in the same group?

• Aa cowa shoea baby

• Ba doctor's officea post officemusic

• Ca zippera sharka comb

• Drestaurant goera birdthe Senate

• Ea potatoa hurricanea target

• Fa rivera persona cave

The rope ladder of a boat hangs over the side of the boat and just reaches the water. Its rungs are 8

inches apart. How many rungs will be under the water when the tide rises 4 feet?

Rising Tide

Scientific Method &Experimental Design

NOTEBOOK TIME!!

Solving Problems

• To answer questions scientists use an organized system called the Scientific Method:

• Some questions are solved quickly• Some over years • Some never get solved

Basic SM

• Question • Test • Analyze • Conclude

Steps of the Method

• State a problem• Gather information (research,

observations)• Form a hypothesis• Perform an experiment to test the

hypothesis• Record & analyze data• State a conclusion• Repeat the work

The Scientists

• Francesco Redi (Italian 1668)

• Lazzaro Spallanzani (Italian 1767)

• Louis Pasteur (French 1864)

Scientists and Scientific Method

•Francesco Redi - One of the first to disprove spontaneous generation. An Italian doctor who proved maggots came from flies. (Italian 1668)

•Lazzaro Spallanzani - One of the first to disprove spontaneous generation. An Italian scientist who proved microorganisms could be killed by boiling. (Italian 1767)

•Louis Pasteur - One of the first to disprove spontaneous generation. A French scientist who proved that micro organisms was carried by dust not air. (French 1864)

Groups -

• Use Textbooks and online textbook (active art) to complete the following information in your notebook for each scientist

Problem/Question

Hypothesis

Experimental Design•Manipulated Var.•Responding Var.•Control•Constants

Redi Spallanzani Pasteur

It’s All in the Details

Creating testable hypotheses

Experimental Variables

SCIENTIFIC METHODSteps List

• Observations• Problem/Question?-• Hypothesis – “If….. Then….. Because…..”• Experiment process to test hypothesis:

– Manipulated (Independent) Variable –– Responding (Dependent) Variable –– Control Group– Constants

• Data collection and graphing• Conclusion: a summary of analysis of findings

Creating a Hypothesis

• Based on a small amount of information

• Often an “If – Then -- Because statement”

• Needs to be testable

• Needed for experimentation

Make a hypothesis

• You notice that your scores on your tests in biology over the past month. You want to improve your test scores.

• Form a hypothesis:

Where to Start

• To get precise results that are accepted by other scientists, you need:

– a specific hypothesis

– design a specific experiment

Parts of an experiment

• In an experiment there are two variables

– Independent variable– Dependent variable

Independent variables

• This is the part of the experiment that is deliberately changed from the beginning of the experiment

• The factor that is being tested

Dependent variable

• This is the part of the experiment that is measured

• This measurement tells the scientists if the independent variable has an effect on the outcome of the experiment

• 2 kinds:– Quantitative & Qualitative

Trials & Sample Size

• Set up multiple trials based on the IV– Everything is the same except the factor

being tested

• Make sure to test more than 1 per trial – Why?

Designing of Experiment

• In addition to the variables some experiments allow for a control– An experiment where there is not IV – no

treatment

The Control

• Makes sure that the experiment tests the independent variable

• How?– Hold all factors at “normal”

• Used for comparison

Constants

• It is important in a controlled experiment to only test one variable – the IV!

• So, must keep other factors constant

• Ex – if we want to test the effect of the amount of water on plant growth, what other factors should be held constant?

The Results

• Results either support or do not support the hypothesis

• RESULTS DO NOT PROVE ANYTHING

Scientific Hypothesis

• A possible explanation for an observation based on a small amount of information

Scientific Law

• A basic principle that describes behavior of a natural phenomenon. A rule of nature. Explains what will happen.

Scientific Theory

• A well tested explanation, supported by an overwhelming amount of evidence & is accepted by the majority of scientists. Explains Why

• Often used to explain scientific laws

Practice your skills

• Identify the various elements of scientific method

AND

• Identify experimental errors

Scenario 1

• Compost and Bean Plants– Different aged grass compost on bean plant

growth– Older compost should produce taller bean

plants– 3 flats (25 plants per flat): Flat A given 3

month old compost, Flat B given 6 month old compost and Flat C no compost

– Plant height recorded after 30 days

Scenario 2

• Metals and Rusting– Utilities company burying lead next to iron pipes to

prevent rusting– Perhaps more active metals will be better at

preventing rusting– Placed following into separate beakers of water: a) 1

iron nail b) 1 iron nail wrapped in aluminum c) 1 iron nail wrapped in magnesium d) 1 iron nail wrapped in lead

– Same amount of water used in each and at end of 5 days rated amount of rust

Scenario 3

• Certain perfume esters agitate bees, wanted to know if Ester X was present in 4 different perfumes by observing bee behavior

• Placed 10 mL of first perfume 30 m from hive, recorded time for bees to emerge and behavior

• Allowed for 30 min recovery then repeated with additional perfumes

Scenario 4

• Fossils and Cliff Depth– Observed that different types and amounts of

fossils were present in a cliff behind home– Marked bank at five positions: 5, 10, 15, 20

and 25 m from surface– She removed 1 bucket of soil from each of the

positions and determined kind and number of fossils in each sample

Scenario 5

• Aloe vera and Planaria– Aloe vera is to promote healing of burned tissue so it

might help with regeneration of planaria.– Bisected planaria to obtain 10 parts (5 heads and 5

tails)– Applied 0%, 10%, 20%, 30%of aloe vera to the

groups– 15 mL of solutions were applied. All planaria kept in

same chamber with same temp, food, etc– On day 15 Jackie observed the regeneration and

categorized as full, partial or whole

SCIENTIFIC METHODand the Snowshoe Hare

• Observations –

• Problems (?)-

• Hypothesis –

• Manipulated (Independent) Variable –

• Responding (Dependent) Variable –

• Control Group

• Constants