The document explains three types of variables in scientific experiments: independent, dependent, and controlled variables. It provides multiple examples illustrating how to identify these variables, such as in experiments involving students assembling puzzles, electromagnetic systems, boiling eggs, plant growth under different colored lights, and parachute sizes. Each example clarifies how changes in the independent variable affect the dependent variable while keeping controlled variables constant to ensure fair testing.

1. Identifying
Variables

2. 3 types of variables
1. Independent variable
2. Dependent variable
3. Controlled variable

3. Independent Variable a.k.a Manipulated
Variable
-Something that is intentionally
changed by the scientist
- What can you control?
- What is manipulated?
- What is tested?
+Key word: Different

4. Dependent Variable a.k.a
Responding Variable
- Something that might be affected by
the change in the independent variable
- What is observed?
- What is measured?
- The data collected during the
investigation

5. Controlled Variable a.k.a
Constant Variable
- A variable that is not
changed
- Allows the experiment
to be fair

6. Example:
Students of different ages
were given the same jigsaw
puzzle to assemble. They
were timed to see how long it
took to finish the puzzle.

7. IDENTIFY THE
VARIABLES IN THE
INVESTIGATION

8. What was the Independent
Variable?
- Ages of the students
 Different ages were
tested by the scientist

9. What was the Dependent
Variable?
- The time it to put the
puzzle together
 The time was observed
and measured by the
scientist

10. What were the Controlled
Variables?
-Same puzzle -
 All of the participants were
tested with the same puzzle.
 It would not have been a fair
test if some had an easy 30
piece puzzle and some had a
harder 500 piece puzzle.

11. Another Example:
An investigation was done with an
electromagnetic system made
from a battery and wire wrapped
around a nail. Different sizes of
nails were used. The number of
paper clips the electromagnet
could pick up was measured.

12. IDENTIFY THE
VARIABLES IN THE
INVESTIGATION

13. What was the Independent
Variable?
- Sizes of nails
These were
changed by the
scientist

14. What was the dependent
variable?
- Number of paper clips
picked up
 The number of paper
clips observed and
counted (measured)

15. What were the Controlled
Variables?
-Battery, wire & type of
nail
 None of these items were
changed during the
experiment

16. One more Example:
The higher the temperature of
water, the faster an egg will
boil.

17. IDENTIFY THE
VARIABLES IN THE
INVESTIGATION

18. What was the Independent
Variable?
- Temperature of the water
 The scientist changed the
temperature in the
experiment

19. What was the Dependent
Variable?
- Time to cook an egg
 The scientist was trying to
see how fast the egg will
boil because of the
temperature

20. What were the Controlled
Variables?
-Type of egg
 The type of egg was not
changed during the
experiment

21. Last Example:
Does changing the color of
light affect the growth rate of
plants?

22. IDENTIFY THE
VARIABLES IN THE
INVESTIGATION

23. What was the Independent
Variable?
- The color of the light
 The scientist changed
the color during the
experiment

24. What was the Dependent
Variable?
- Growth rate of plants
 It depends on the color of
light, which is the
independent variable

25. What were the Controlled
Variables?
- Same type of plant
- Same wattage of bulb
- Same soil
- Light on for the same
amount of time

26. Really Last Example:
How does the size of a
parachute affect the time it
takes a hippo to fall 10 feet?

27. IDENTIFY THE
VARIABLES IN THE
INVESTIGATION

28. What was the Independent
Variable?
-The size of the
parachute
The size of the
parachute is the
one being changed

29. What was the Dependent
Variable?
- The time it takes a hippo to
fall at 10 feet
 It depends on the parachute
size, which is the
independent variable

30. What were the Controlled
Variables?
- Same hippo
- Dropped from the same
height
- Same parachute fabric
- Same length of strings
on the parachute

31. Answer
these
Questions!
HOMEWORK

32. FOR WATCHING!