1. Or what changes during experiments….
What are variables?
Or what changes during experiments….

2. Independent Variables
What is tested by the scientist
What is changed by the scientist
Also known as manipulated variables.

3. Dependent Variable What is observed What is measured
The effect caused by the independent variable.
The data
Also called responding variables

4. Controlled Variables Things that could change but don’t
Kept constant (the same) by scientists
These allow for a fair test.

5. Identify the variables in this investigation.
Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.
Identify the variables in this investigation.

6. Time it took to put the puzzle together.
Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle. What is the independent variable?
Same Jigsaw Puzzle
Different Ages
Time it took to put the puzzle together.

7. What was the independent variable?
Ages of the students
Different ages were tested by the scientist

8. Time it took to put the puzzle together.
Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle. What is the dependent variable?
Same Jigsaw Puzzle
Different Ages
Time it took to put the puzzle together.

9. What was the dependent variable?
The time it to put the puzzle together
The time was observed and measured by the scientist

10. Time it took to put the puzzle together.
Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle. What is a controlled variable?
Same Jigsaw Puzzle
Different Ages
Time it took to put the puzzle together.

11. What was a controlled variable?
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.

12. Another example:

13. Number of paper clips picked up Size of nails Type of nail
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. What is the independent variable?
Number of paper clips picked up
Size of nails
Type of nail

14. Independent variable:
Sizes of nails
These were changed by the scientist

15. Number of paper clips picked up Size of nails Type of nail
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. What is the dependent variable?
Number of paper clips picked up
Size of nails
Type of nail

16. Number of paper clips picked up
Dependent variable:
Number of paper clips picked up
The number of paper clips observed and counted (measured)

17. Number of paper clips picked up Size of nails Type of nail
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. What is a control variable?
Number of paper clips picked up
Size of nails
Type of nail

18. Controlled variables:
Battery, wire, type of nail
None of these items were changed

19. One more:

20. The higher the temperature of water, the faster an egg will boil.

21. The higher the temperature of water, the faster an egg will boil
The higher the temperature of water, the faster an egg will boil. What is the independent variable?
Temperature of water
Time it takes to boil
Egg

22. The higher the temperature of water, the faster an egg will boil
The higher the temperature of water, the faster an egg will boil. What is the dependent variable?
Temperature of water
Time it takes to boil
Egg

23. The higher the temperature of water, the faster an egg will boil
The higher the temperature of water, the faster an egg will boil. What is the control variable?
Temperature of water
Time it takes to boil
Egg

24. Independent variable – temperature of water
Dependent variable – time to cook an egg
Controlled variable – type of egg

25. Last one:

26. The temperature of water was measured at different depths of a pond.

27. Thermometer Depth of the water Temperature
The temperature of water was measured at different depths of a pond. What is the independent variable?
Thermometer
Depth of the water
Temperature

28. Thermometer Depth of the water Temperature
The temperature of water was measured at different depths of a pond. What is the dependent variable?
Thermometer
Depth of the water
Temperature

29. Thermometer Depth of the water Temperature
The temperature of water was measured at different depths of a pond. What is the control variable?
Thermometer
Depth of the water
Temperature

30. Independent variable – depth of the water
Dependent variable – temperature
Controlled variable – thermometer