1. Variables Review

2. Dependent Variable What is being tested or measured. What is being tested or measured.

3. Independent Variable What the Scientist is changing. 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 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 D.V. – the time it takes to run a mile I.V. – the amount of exercise the person is getting 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. The higher the temperature of water, the faster an egg will cook.

8. Answer D.V. – the time it takes to boil the egg D.V. – the time it takes to boil the egg I.V. – the temperature of the water 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. 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 D.V. – the number of eggs laid I.V. – the amount of time the light is left on 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. The amount of pollution produced by cars was measured using gasoline containing different amounts of additive.

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

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

14. Answer D.V. – the size of the lemons D.V. – the size of the lemons I.V.- the amount of water that the tree receives 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. 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 D.V. – The amount of algae in the lake I.V. – the amount of fertilizer sold by the local merchants 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. 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 D.V. – the mass of the rat I.V. – the amount of vitamin C that that the rat receives each day. 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? 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 D.V. – the number of nails that the magnet can pick up I.V. - the strength of the magnet 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. 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 D.V. – the size of the illuminated area I.V. – the distance from the screen I.V. – the distance from the screen

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

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