1. designing an
Experiment

2. A variable is something that changes.

3. 6 components of an experiment
independent variable
dependent variable
constants
control group
experimental group
repeated trials

4. the variable that is changed on purpose by the experimenter
independent variable
the variable that is changed on purpose by the experimenter
aka cause, stimulus, reason, manipulated variable, etc.

5. the variable that changes in response to the independent variable
aka effect(s), result(s), responding variable, etc.

6. all the factors which are NOT allowed to change during the experiment
constants
all the factors which are NOT allowed to change during the experiment

7. the group (standard) to which everything is compared
control group
the group (standard) to which everything is compared

8. the group(s) being tested using the independent variable
experimental group
the group(s) being tested using the independent variable
Each test group has only one factor different from the other test groups: the independent variable.

9. the number of times the experiment is repeated
repeated trials
the number of times the experiment is repeated
An experiment should be carried out many times to produce accurate/ repeatable results

10. Before carrying out an experiment, you MUST identify your independent variable, constants and dependent variable.

11. 6 drops fertilizer
4 drops fertilizer
2 drops fertilizer
no fertilizer

12. EXPERIMENTAL GROUP CONTROL 2 drops fertilizer 4 drops fertilizer
What is this called?
What are these called?
CONTROL
EXPERIMENTAL GROUP
no fertilizer

13. What are these called?
CONSTANTS

14. dependent variable What is this called?
The plant growth that you observe here can be called . . .
 the results (of adding fertilizer)
 the response (to adding fertilizer)
dependent variable
 the effects (of adding fertilizer) 2 4 6

15. forming a
hypothesis

16. A good hypothesis: - Is a statement (NOT a question)
- Is written in clear and simple language
- Relates the independent and dependent variables
Is testable
Can be written in several ways (including if, then statement)

17. Write a hypothesis for the plant experiment in the box in your notes.

18. Good! Warm water will dissolve more salt than cold water.
Good or Bad Hypothesis?
Warm water will dissolve more salt than cold water.
Good!
What is another way this hypothesis can be written?

19. Bad Will fertilizer make my lawn grow more?
Good or Bad Hypothesis?
Will fertilizer make my lawn grow more?
Bad
How can you make this a good hypothesis?

20. recording and displaying
Results

21. iv
constants dv
fertilizer
plant growth
0 drops
Results from your experimentation should be recorded in a carefully constructed data table.
2 drops
4 drops
6 drops

22. A data table has at least 2 columns of information.iv
constants dv
fertilizer
plant growth
0 drops
1 cm
2 drops
1.5 cm
4 drops
1.5 cm
6 drops
3 cm
A data table has at least 2 columns of information.

23. Independent variable data is always. (a) recorded in the left column
Independent variable data is always (a) recorded in the left column (b) recorded BEFORE experimentation
fertilizer
0 drops
2 drops
4 drops
6 drops IV

24. fertilizer
fertilizer (drops)
0 drops 2 4 6
2 drops
4 drops
6 drops

25. Dependent variable data is always. (a) recorded in the right column
Dependent variable data is always (a) recorded in the right column (b) recorded DURING experimentation
plant growth
1 cm
1.5 cm
3 cm
fertilizer (drops) DV 2 4 6

26. plant growth 1 cm 2 4 6 1 1.5 3 1.5 cm 1.5 cm 3 cm fertilizer (drops)2 4 6 1
1.5 3
1.5 cm
1.5 cm
3 cm

27. Choose an appropriate title for the data table.
Effect of Fertilizer on Plants Growth
fertilizer (drops)
plant growth (cm) 2 4 6 1
1.5 3

28. Effect of Fertilizer on Plants
Data from a correctly constructed data table can be displayed in a graph.
fertilizer (drops) 2 4 6
plant growth (cm) 1
1.5 3
Effect of Fertilizer on Plants

29. IV data is plotted on the X axis. DV data is plotted on the Y axis.
fertilizer (drops) 2 4 6
plant growth (cm) 1
1.5 3
Effect of Fertilizer on Plants
1.0
2.0
1.5 .5
2.5
3.0
plant growth (cm) 2 4 6
fertilizer (drops)

30. The title of the data table is also the title of the graph.
fertilizer (drops) 2 4 6
plant growth (cm) 1
1.5 3
Effect of Fertilizer on Plants
Effect of Fertilizer on Plants
1.0
2.0
1.5 .5
2.5
3.0
plant growth (cm) 2 4 6
fertilizer (drops)