AI Tutor
If you test two paper airplanes, but throw one gently inside and launch the other outside in the wind, you won't know which design is actually better.
To run a fair test, scientists carefully manage every factor that can change, which we call variables.
How do scientists organize these parts to discover true cause-and-effect relationships?

The Three Types of Variables

Every experimental investigation relies on three specific types of variables: the independent variable, the dependent variable, and controlled variables.
A handy memory trick is that the independent variable is what I change, while the dependent variable is the data you measure.
How do we spot each of these variables in a real classroom experiment?

Worked Example: Plant Growth

Maya asks a scientific question: Does the amount of daily sunlight affect how tall bean plants grow?
She sets up three identical pots with bean seeds: Pot A receives 2 hours of sunlight each day, Pot B gets 6 hours, and Pot C gets 10 hours.
In Maya's test, the independent variable is the amount of sunlight because that is the single condition she purposefully changed.