8th Grade ScienceSeptember 14, 2010

Ms. McKinley

What is the Scientific Method?

The process that scientists use to solve real-world problems or answer real-world questions.

WHAT problem have we looked at so far in this class? (OR, what question have we tried to

answer in this class?)

Steps in the Scientific Method

WARNING!! This is not always a step by step process. Sometimes you add steps, sometimes you go back to a certain step. This is a simple model.

Observation/Problem

Ask a Question

Form a Hypothesis

Test the Hypothesis

Analyze Results/ Draw Conclusion

Scientific Questions MUST be TESTABLEThis means you should

be able to design an experiment that would help to answer the question.

YOU decide:Which ones are “TESTABLE”?1. Which brand of skateboard is better?2. Which brand of skateboard is the strongest?3. Should I paint my bike?4. What happens when you leave a bike in the rain?5. Which brand of cleaner works best?6. Which kind of plant food makes plants grow the

most?7. Which exercise program will help me lose the most

weight?8. Why do dogs bark?9. Why do babies cry? 10. What types of objects fly?

Form a Hypothesis Your answer to a scientific question.

An explanation that can be tested w/ a scientific experiment

What VARIABLES were in the BrainPop video experiment?What VARIABLES were in Lab #1 (Paper Airplane Lab)?

Testing your HypothesisAs the scientist, you

decide:What you will doWhat you are looking forWhat you will measure

VariablesAnything that can vary in

your experiment.

ConstantsWhat does not change in

your experiment.

Variables: 2 Types Independent (IV):The factor you want to test.EXAMPLE: The type of

paper used

Dependent (DV):The factor you measure or

observe.EXAMPLE: The distance

each plane flew

Let’s look at an example…You have just been

hired as a skate deck designer at Element skateboards.

Your first job is to answer the following question:How does

changing the material in a skateboard deck affect a skater’s ollie height?

Experiment setupYou design a new

skateboard deck that has a special layer built inside.

You will test to see if this special layer makes any difference on ollie height.

Experiment setup:You bring in 10 skaters

and split them up into two groups of 5:GROUP A (experimental

group) gets a new, modified Element skateboard WITH the special layer.

GROUP B (control group) gets a new, unmodified Element skateboard WITHOUT the special layer.

Both skateboard types are the SAME style, color, shape, size, wheels, trucks, same everything.

Only difference is the special layer in the deck.

So far, what are the CONTROLS in this experiment?

Set up continued..1. Have all skaters

skate around on their new boards for 3o min to get used to them.

2. Then, test each skater’s ollie height.

3. For each skater, measure ollie height in meters. Do this 5 times, and calculate the average height.

Stop, and think about it…Skateboard design experiment example:

IV:DV:Constants:

Stop, and think about it…Skateboard design experiment example:

IV: Skateboard design type (modified or unmodified)

DV: Ollie height (meters)

Controls All skaters get new board Same shape, size, wheels, trucks, etc.

Getting accurate data Experimental vs. Control groupsExperimental: IV

changesControl: IV does not

change

Multiple TrialsDo the test several

times