Experimental design questions on ACT Science ask about variables, controls, and what a study actually tests—identify independent, dependent, and controlled variables before you read the answer choices. They appear most in Research Summaries passages.
Core vocabulary
- Independent variable: what the scientist changes
- Dependent variable: what is measured
- Control: baseline for comparison; constants held fixed
Strategy context in best ACT Science strategy.
What they ask
- Which trial is the control?
- What would be a fair comparison?
- What change would test a new hypothesis?
- Which factor would confound results if not held constant?
How to answer
Read the experiment description once for purpose, then locate tables that match the question. Do not import outside science knowledge—only what the passage states. Graph speed helps in reading graphs faster.
Common traps
Confusing correlation with causation, picking a variable that was never manipulated, or ignoring units. If Science is optional for you, confirm need in is ACT Science optional.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
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