The Scientific Method

Chapter 1

The Scientific Method

Mrs. Wolfe

What is Science?

• Science is a way of answering questions!

• Clip from “Myth Busters”

Observations & Inferences

• What’s the difference?

Time for a Lab!

Lab Recap…

• Observations – data that is collected using your 5 senses

• Inference – a conclusion that you make from your observations

What is “The Scientific Method?”

What is a Hypothesis?

• An educated guess that can be tested.

• 1. If plants are given Miracle Grow, then they will grow faster.

• 2. If frogs in the NW are exposed to nitrogen in their water, then they will deform.

• “If….., then……”

Is this an acceptable hypothesis?

• 3. If the doorknob is loose, then the door will squeak. – Is it educated? – Is it testable?

• YES!!

OK, so let’s do an experiment….

I need a hypothesis…

If an apple is cut and refrigerated, then it will rot faster.

• In this experiment, we put the cut apple in the refrigerator with a whole apple.

• Why did we put the whole apple in the refrigerator?

For COMPARISON!!

The COMPARISON is NECESSARY!

• Experimental Group – receives treatment (cut apple)

• Control Group –used to compare (whole apple)

Designing an Experiment

• Everything about these two groups must remain exactly the same except the ONE variable you are testing. – Both are apples (not an orange and an apple).– Both are the same kind of apple.– Both apples were the same age (bought at the same

time).– The only difference: 1 was cut and 1 was whole

More About Experimenting• Independent variable

What you do to your experimental group

• Dependent variable

What you measure

What is the independent variable?What is the dependent variable?

No Fertilizer Added Fertilizer Added

What KIND of data is collected?

• Quantitative Data – describes the quantity and involves numbers.– 4 butterflies

• Qualitative Data – describes the quality or appearance.– Orange and Yellow butterflies

•

Every conclusion is “true to the best of our knowledge.”

There is no absolute proof.

The data SUPPORTS or DOES NOT SUPPORT our hypothesis.

It NEVER PROVES our hypothesis.

Let’s draw a conclusion.

• This data was taken from the Plants with Fertilizer experiment. – Hypothesis: If plants are

given fertilizer, they will grow taller.

• What kind of data is this?• Is the hypothesis

supported or not?

Experimental Control

5 cm 4 cm

8 cm 6 cm

16 cm 9 cm

18 cm 11 cm