Variables Review

Dependent Variable What is being tested or measured.

Independent Variable What the Scientist is changing.

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

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

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

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

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

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.

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

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

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

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

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

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.

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

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.

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

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

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

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.

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

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

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