1. Which variable should be changed in an experiment to test how much sodium bicarbonate will dissolve in water at 25°C? A). The temperature of the water.
B). The amount of sodium bicarbonate.
C). The amount of sodium chloride.
D). The amount of water.

2. Why is it important to have a "controlled" experiment?

A). To change only one variable at a time.
B). To answer multiple questions at once.
C). To control the results of the experiment.
D). To keep all the variables the same.

3. Which variable should be changed in an experiment to test the best snack for a pet bird?

A). The type of bird in the experiment.
B). The types of toys provided to the bird.
C). The type of food provided to the bird.
D). The type of cage the bird lives in.

4. Which variables should be controlled in the experiment to test what type of exercise will build the most muscle? Select all that apply.

A). The starting weight of the participants.
B). The length of time the participants exercise.
C). The diet the participants eat.
D). The ending weight of the participants.

5. Using the scientific process, how can we set up a controlled experiment to answer the question: “Does the temperature of water affect the amount of copper sulfate water will dissolve?”

A). Establish distilled water and tap water, and test how much copper sulfate will dissolve in each water type. All other variables should remain constant.

B). Establish two different amounts of copper sulfate, and test whether each will dissolve in the same amount of water. All other variables should remain constant.

C). Establish two different amounts of water, and test whether the same amount of copper sulfate will dissolve in each amount. All other variables should remain constant.

D). Establish two different temperatures of water, and test how much copper sulfate will dissolve at each temperature. All other variables should remain constant.

6. Which variable should be changed in an experiment to test the best conditions for bacteria to grow?

A). The size of the original colony of bacteria.
B). The length of time that the bacteria are left alone.
C). The type of bacteria used.
D). The material that the bacteria feed upon.

7. What variable should be changed for an experiment to test which brand of bread stays fresh the longest?

A). The length of time that the bread sits.
B). The brand of bread that is used.
C). The day the bread is bought.
D). The place the bread is left to sit.

8. Which groups should be used in the experiment to test which drink contains the most caffeine? Select all that apply.

A). A 12 oz sample of soda.
B). A 12 oz sample of iced coffee.
C). A 12 oz sample of ice.
D). A 12 oz sample of water.

9. An experiment is designed to determine the viscosity of honey flow at different temperatures. What is the control group for the experiment?

A). Honey at 20˚C
B). Honey at 50˚C
C). Honey at 75˚C
D). Honey at room temperature