1. Variables Review

2. Dependent Variable
What is being tested or measured.

3. Independent Variable
What the Scientist is changing.

4. How can I remember?
DEPENDENT VARIABLE depends on the INDEPENDENT VARIABLE

5. Example 1
The time it takes to run a mile depends on the amount of daily exercise a person gets

6. Answer D.V. – the time it takes to run a mile
I.V. – the amount of exercise the person is getting

7. Example 2
The higher the temperature of water, the faster an egg will cook.

8. Answer D.V. – the time it takes to boil the egg
I.V. – the temperature of the water

9. Example 3
An investigation was conducted to see if keeping the lights on for different amounts of time each day affected the number of eggs chickens laid.

10. Answer D.V. – the number of eggs laid
I.V. – the amount of time the light is left on

11. Example 4
The amount of pollution produced by cars was measured using gasoline containing different amounts of additive.

12. Answer D.V. – the amount of pollution
I.V. – the amount of additive in the gasoline

13. Example 5
Lemon trees receiving the most water produce the largest lemons.

14. Answer D.V. – the size of the lemons
I.V.- the amount of water that the tree receives

15. Example 6
The amount of algae growth in a lake seems to be directly related to the number of bags of fertilizer sold by the local merchants.

16. Answer D.V. – The amount of algae in the lake
I.V. – the amount of fertilizer sold by the local merchants

17. Example 7
Five groups of rats are fed identical diets except for the amount of Vitamin A that they receive. Each group gets a different amount. After three weeks on the diet, the rats are weighed to see if the amount of Vitamin A received affected their mass.

18. Answer D.V. – the mass of the rat
I.V. – the amount of vitamin C that that the rat receives each day.

19. Example 8
Will the number of nails picked up by a magnet increase if the magnet is stronger?

20. Answer D.V. – the number of nails that the magnet can pick up
I.V. - the strength of the magnet

21. Example 9
Students in science class conducted an investigation in which a flashlight was pointed at a screen. They wished to find out if the distance from the light to the screen had any affect on the size of the illuminated area.

22. Answer D.V. – the size of the illuminated area
I.V. – the distance from the screen

23. Example 10
The farther a ball is dropped, the higher it will bounce.

24. Answer
D.V. – the height of the bounce
I.V. – the height of the drop