In an experiment, what is the dependent variable?

• A. What you change on purpose
• B. What you measure
• C. The constant conditions
• D. The equipment used

Answer: (B)

The dependent variable is the outcome you observe and measure to see how it changes in response to what you deliberately vary. It’s the data you collect to understand the effect of your experimental conditions. Think of it as the result that depends on the thing you intentionally change.

For example, if you change the amount of fertilizer to see how tall a plant grows, plant height is the dependent variable because you measure it to see how it responds. The amount of fertilizer is the independent variable because you control and vary it on purpose. The constant conditions stay the same to ensure any observed differences come from your variable of interest, and the equipment is just part of the setup.