Understanding the Independent Variable

Understanding the Independent Variable

Read each question carefully and identify the independent variable in the described scientific experiments. The independent variable is the factor that is changed or controlled by the experimenter.

1. A scientist wants to see if different types of fertilizer affect plant growth. She sets up three groups of plants: one with Fertilizer A, one with Fertilizer B, and one with no fertilizer. All plants receive the same amount of water and sunlight. What is the independent variable?

2. A student is testing how the temperature of water affects how quickly sugar dissolves. She prepares three cups of water: one with cold water, one with room temperature water, and one with hot water. She adds one spoon of sugar to each cup and times how long it takes to dissolve. What is the independent variable?

3. The independent variable is the factor that the scientist   or changes in an experiment.

4. In an experiment, you should only have one   variable to ensure a fair test.

5. The independent variable is the outcome that is measured in an experiment.

6. Changing the independent variable helps us see if it causes a change in the dependent variable.

7. A scientist wants to find out if the amount of light affects how tall a plant grows. Describe what the independent variable would be in this experiment.

8. Look at the image below of a scientific experiment setup. Imagine this experiment is testing how different amounts of water affect the size of a bean sprout. Identify the independent variable.