TEAS® Science Study Guide
Variables
A variable is anything in an experiment that can change. Telling the types apart is the single most-tested skill in this section.
- Independent variable — The one thing the experimenter deliberately changes. The suspected cause.
- Dependent variable — What the experimenter measures. It responds to the independent variable — the effect.
- Controlled variables (constants) — Everything kept the same so the test is fair.
A memory aid: the dependent variable depends on the independent one. And you (I) change the independent variable.
An example: to test whether fertilizer affects plant growth, you give plants different amounts of fertilizer and measure how tall they grow.
- Independent variable: amount of fertilizer (what you change)
- Dependent variable: plant height (what you measure)
- Controlled variables: sunlight, water, pot size, soil type (kept the same for every plant)
Control group vs. experimental group
- The experimental group receives the treatment being tested.
- The control group does not, and serves as the baseline for comparison. In the plant example, the control group gets no fertilizer.
Terms to know
- Independent variable — What you change.
- Dependent variable — What you measure.
- Controlled variable — What you keep constant.
- Control group — The untreated baseline group.
What the TEAS asks most
- Which variable does the experimenter change? Independent.
- Which variable is measured? Dependent.
- What is the purpose of a control group? To provide a baseline for comparison.
- Why keep other variables constant? So only the independent variable can affect the result.