1. Hypothesis and Variables

2. Step 3: Form a Hypothesis
Hypothesis- a testable explanation of an observation.
A hypothesis is NOT just an educated guess about what you think will happen. It must be able to be tested!

3. Step 3: Form a Hypothesis
We write the hypothesis in an If-Then statement
ex: If the amount of fertilizer is increased, then the height of the plant will increase.

4. Variables & Controls
A variable is anything that changes in a scientific experiment.
The control is what you use to compare the results to in the end of the experiment.

5. There are 2 types of variables:
Independent
Dependent

6. Step 3: Form a Hypothesis
The Independent Variable goes after the “If”
I.V.
If the amount of fertilizer is increased,
then the height of the plant will increase.

7. Step 3: Form a Hypothesis
The Dependent Variable goes after the “Then”
If the amount of fertilizer is increased,
then the height of the plant will increase.
D.V.

8. Now You Try:
If you spend more time studying, then your grade will improve.
Independent Variable =
Dependent Variable =

9. Now You Try:
If you spend more time studying, then your grade will improve.
Independent Variable = amount of time spent studying
Dependent Variable = grade

10. Now You Try:
If the temperature of the room is increased, then the bacteria will grow faster.
Independent Variable =
Dependent Variable =

11. Now You Try:
If the temperature of the room is increased, then the bacteria will grow faster.
Independent Variable = temperature of room
Dependent Variable = bacterial growth

12. Variables & Controls
A variable is anything that changes in a scientific experiment.
The control is what you use to compare the results to in the end of the experiment.

13. 2 Types of variables: Independent Variable: What you change.
Dependent Variable: What changes because of the Independent Variable.

14. 2 Types of variables: Independent Variable: Cause
Dependent Variable: Effect

15. Independent Variable Independent Variable: What you change. Cause
a.k.a Manipulated Variable
Graphed on x axis

16. Dependent Variable
Dependent Variable: What changes because of the Independent Variable.
Effect
a.k.a Responding Variable
Graphed on y axis

17. Independent Variable vs. Dependent Variable
Also Known As:
Manipulated Variable
Responding Variable
Results:
Cause
Effect
On a graph:
X axis
Y axis

18. After all of the data from the experiment is collected, then its time to organize the data.

19. Step 6: Organize your data
Put your data into a data table
Independent
Variable
__________(unit)
Levels
Dependent Variable _______________ (unit)
Trial Trail Trail mean range

20. Step 6: Organize your data
Make the data table into a graph
GRAPHS make it EASIER to see patterns in the data!

21. Step 6: Organize your data
How do you know what goes on each axis of the graph?

22. Step 6: Organize your data
DRY MIX
Dependent Variable = Responding Variable = Y axis
Manipulated Variable = Independent Variable = X axis

23. Parts of a graph
Y Axis
X Axis

24. Y Axis (Dependent Variable) X Axis (Independent Variable)
Parts of a graph
Y Axis (Dependent Variable)
X Axis (Independent Variable)

25. Graphing: DRY MIX
Dependent Variable
Independent Variable

26. Any Questions????