1. Steps of the Scientific Method

2. Define the problem.
(Ask the question.)
State the hypothesis.
(Suggest an answer.)

3. A suggested solution to the problem Must be testable
Hypothesis
A suggested solution to the problem
Must be testable
Predicts an outcome

4. Rules in Constructing a Hypothesis
Do not use I, me, my, they – no possessive pronouns.
It can be written as an if-then statement.
It is a statement, not a question.
Example:
If salt is added to fresh water, then the water will take longer to freeze.

5. Perform experiments.
A. Types of experiments
1. lab
2. field study—observation made in a natural setting

6. [Experiments continued]
B. Parts of an Experiment:
1. control group—the group in which all conditions are kept the same as normal; used for comparison
2. experimental group—the group which receives the variable being tested

7. Experiment (continued)
3. data—information from experiments 4. variable—any part of an experiment that can be changed

8. Brain Break

9. [Experiments continued]
C. Types of variables:
1. independent—the one factor being tested; the only thing different between the groups
2. dependent—the factor being measured or observed to give the results
3. controlled—all of the factors kept the same for the groups; should be many

10. Example of Controls & Variables
For example, suppose you want to figure out the fastest route to walk home from school.
You will try several different routes and time how long it takes you to get home by each one.
Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

11. What are the Variables in Your Experiment?
Varying the route is the independent variable.
The time it takes is the dependent variable.
Keeping the same walker throughout makes the walker a control variable.

12. D. In a good (valid) experiment: 1
D. In a good (valid) experiment: 1. ALL variables should remain the same except for the ONE being tested (independent variable). 2. Repetitions should give similar data. 3. Dependent variables should be measurements. 4. Scientific bias is not present. bias—preconceived notions, opinions, or other factors that would affect the data

13. DRY—Dependent or Responding variable goes on the Y-axis!
MIX—Manipulated or Independent variable goes on the X-axis!

14. Draw conclusions.
The conclusion will either PROVE (accept) or DISPROVE (reject) the hypothesis.
5. Communicate results.

15. A. scientific law—a summary of lots of scientific data; describes WHAT happens; Ex: law of gravity (What goes up MUST come down!) B. scientific theory—an explanation of WHY things work as they do; Ex: theory of evolution