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. Types of Variables:

5. The Independent Variable goes after the “If”
I.V.
If the amount of fertilizer is increased,
then the height of the plant will increase.

6. The Dependent Variable goes after the “Then”
If the amount of fertilizer is increased,
then the height of the plant will increase.
D.V.

7. Now You Try:
Example 1
If you spend more time studying, then your grade will improve.
Independent Variable =
Dependent Variable =

8. Now You Try:
Example 1
If you spend more time studying, then your grade will improve.
Independent Variable = amount of time spent studying
Dependent Variable = grade

9. Now You Try:
Example 2
If the temperature of the room is increased, then the bacteria will grow faster.
Independent Variable =
Dependent Variable =

10. Now You Try:
Example 2
If the temperature of the room is increased, then the bacteria will grow faster.
Independent Variable = temperature of room
Dependent Variable = bacterial growth

11. Independent Variable: Cause
Dependent Variable: Effect

12. Independent Variable vs. Dependent Variable
(I change)
Dependent
Variable
(I observe)
Also Known As:
Manipulated Variable
Responding Variable
Results:
Cause
Effect
On a graph:
X axis
Y axis

13. Time to Practice!

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

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

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

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

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

19. Parts of a graph
Y Axis
X Axis

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

21. Graphing: DRY MIX
Dependent Variable
Independent Variable

22. Any Questions????