Scientific Method

How Scientists Do Science

Science is

A process of Discovery Determining Cause and

Effect

How does this work?

Watch out for BOLD vocabulary words!

Scientific Method

1. Observation – uses 5 senses, a fact

2. Inference – Why do I think (what ever I observed) happened?

3. Hypothesis – Statement of reasonable guess what happened “If….then….”

Scientific Method (cont.)

4. Controlled Experiment – way of testing the hypothesis/guess More on this….

5. Conclusion – seeing if the data from the experiment agrees with the hypothesis It’s ok if it doesn’t!

Lets put Science into Action

Observation Inference Hypothesis Controlled

Experiment Conclusion

Controlled Experiment

The heart of science Eliminates other causes so we can link a

single cause with a single event.

Controlled Experiment

Hypothesis: If the water is polluted, then the fish will die. Cause: Pollution Effect: Death

Set up 2 groups to test the hypothesis Control Group: Normal Conditions

No pollution in the water Experimental Group: Change one thing

Put pollution in the water

Controlled Experiment

Independent Variable – What have I changed? Presence or absense of pollution

Dependent Variable – What will I measure? Number of dead fish

Controlled Experiment Synonyms

Independent Variable

Manipulated Variable

Cause Ex. Pollution

Dependent Variable

Responding Variable

Effect Ex Fish Deaths

Other parts of an experiment

Controlled Variables – all the other stuff that could effect the experiment.

This has to be kept the same between the experimental and control groups.

Data – Chart form

Independent Variable Dependent Variable

No Pollution 43 live fish, 2 dead fish

Pollution 20 live fish, 30 dead fish

Data – Graph form

X axis – Independent Variable – Quantity of Pollution

Y a

xis

– D

epen

dent

Var

iabl

e –

Num

ber

of li

ve f

ish

We will spend more time on graphing as it is ALWAYS on the Regents…and also on your test.

Use the Data to draw a Conclusion

Hypothesis: If the water is polluted, then the fish will die.

Does the data agree (confirm) or disagree (refute) our hypothesis?

It is ok to disprove a hypothesis. What else might be going on?

Are there any new questions that could be asked?

Creative Thinking is Key!Be Curious About the World

Science builds on prior knowledge

There is always more to learn!

Experiment

Experiment

New questions New Questions

New Experiment New Experiment

More new Questions More New Questions More new questions

More new questions

A few more terms

Theory – an accumulated body of knowledge that is well tested and unifies a broad range of observations Gene-Chromosome Theory of Genetics Cell Theory of Life Evolutionary Theory

Law – an accepted fact Law of Gravity