1. Scientific Method

2. Steps in the Scientific Method
Observation
Hypothesis
Experiment
Data Collection
Conclusion
Retest

3. Observations Gathered through your senses
A scientist notices something in their natural world

4. Observations
An example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails

5. Hypothesis A suggested solution to the problem. Must be testable
Sometimes written as If…Then… statements
Predicts an outcome

6. Hypothesis
An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

7. A procedure to test the hypothesis.
Experiment
A procedure to test the hypothesis.

8. Variable – factor in the experiment that is being tested

9. A good or “valid” experiment will only have ONE variable!

10. Controls and Variables
Question: What's an independent variable?
Answer: An independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure.
For example, someone's age might be an independent variable.

11. Question: What's a dependent variable?
Answer: Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors.
For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it.

12. Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in they way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:
(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).

13. Scientific Experiments Follow Rules
An experimenter changes one factor and observes or measures what happens.

14. The Control Variable
The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome.
Those factors are called control variables.

15. What is the Purpose of a Control?
Controls are NOT being tested
Controls are used for COMPARISON

16. Other Variables
The factor that is changed is known as the independent variable.
The factor that is measured or observed is called the dependent variable.

17. 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.

18. 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.

19. One more thing… it is best to make several trials with each independent variable.

20. Valid Experiments

21. Remember: To be a Valid Experiment:
Two groups are required --- the control & experimental groups
There should be only one variable

22. Data Results of the experiment
May be quantitative (numbers) or qualitative

23. Data
Must be organized
Can be organized into charts, tables, or graphs

24. Conclusion
The answer to the hypothesis based on the data obtained from the experiment

25. In order to verify the results, experiments must be retested.

26. Review

27. Solving a Problem 1)Identify a Problem
2) State Observations about the problem
3) Form a Hypothesis about the problem (if…then…)
4) Design an Experiment to test the hypothesis
5) Collect Data
6) Form a Conclusion
7) Retest