Question

for each item below, specify the independent and dependent variables, as well as constants.

1. a study was done to find if different tire treads affect the braking distance of a car.

i: ____________ d: __________ c: ____________

1. the time it takes to run a mile depends on the person’s running speed.

i: ____________ d: __________ c: ____________

1. the height of bean plants depends on the amount of water they receive.

i: ____________ d: __________ c: ____________

1. the higher the temperature of the air in the oven, the faster a cake will bake.

i: ____________ d: __________ c: ____________

1. lemon trees receiving the most water produced the most lemons.

i: ____________ d: __________ c: ____________

1. an investigation found that more bushels of potatoes were produced when the soil was fertilized more.

i: ____________ d: __________ c: ____________

1. students measured the temperature of the water at different depths in lake skywalker and found that the temperature varied.

i: ____________ d: __________ c: ____________

1. the amount of pollution produced by cars was measured for cars using gasoline containing different amounts of lead.

i: ____________ d: __________ c: ____________

1. four groups of rats are first massed and then fed identical diets except for the amount of vitamin a they receive. each group gets a different amount. after 3 weeks on the diet, the rats’ masses are measured again to see if there has been a decrease.

i: ____________ d: __________ c: ____________

Explanation:

For each item, the independent variable (I) is the factor being changed/tested, the dependent variable (D) is the factor being measured/observed, and constants (C) are the factors kept the same to ensure a fair test.

Answer:

1.
I: Tire tread type
D: Car braking distance
C: Same car, road conditions, speed
2.
I: Person's running speed
D: Time to run a mile
C: Same mile course, terrain
3.
I: Amount of water received
D: Height of bean plants
C: Same soil, sunlight, bean plant type
4.
I: Oven air temperature
D: Cake baking speed
C: Same cake recipe, oven type, cake size
5.
I: Amount of water received
D: Number of lemons produced
C: Same lemon tree type, soil, sunlight
6.
I: Amount of soil fertilizer
D: Bushels of potatoes produced
C: Same potato type, soil, sunlight, water
7.
I: Water depth in Lake Skywalker
D: Water temperature
C: Same lake, measurement time, tool
8.
I: Amount of lead in gasoline
D: Amount of pollution from cars
C: Same car type, driving conditions, fuel volume
9.
I: Amount of vitamin A in diet
D: Rat mass change
C: Same rat type, initial mass range, diet (except vitamin A), housing conditions