The Scientific Process: Understanding Variables

When you run an experiment, you need to know exactly what you're changing and what you're measuring. This is where variables come into play. There are three main types you need to understand.

The independent variable is the one factor you deliberately change in your experiment. You should only change one thing to get clear results. For example, if you're studying plant growth, you might use soda instead of water as your independent variable.

The dependent variable is what changes as a result of your independent variable. It's what you measure to see the effects of your experiment. In our plant example, this might be the height or length of the plant after using different liquids.

Remember This: Think of the relationship as cause and effect. You change the independent variable (cause) and then observe what happens to the dependent variable (effect).

Controlled variables are everything else you keep exactly the same across all test subjects. These include the type and size of pot, amount of liquid used, soil type, and anything else that could affect your results. Controlling these variables ensures that any changes you observe are actually caused by your independent variable.