ACT Science / Topic
Research Summaries
Research Summaries passages describe two or more related experiments - the design, the procedure, and the results - and ask about methods, controls, variables, and what changes to the design would do to the outcomes.
What the exam asks
- Identify independent, dependent, and controlled variables in each experiment
- Explain why a step in the procedure was performed (controls, baselines, repetition)
- Compare designs and results across Experiments 1, 2, and 3
- Predict results of a new trial or a modified design from the observed pattern
- Judge which experimental evidence supports or weakens a claim
How to attack this passage type
independent = what they changed; dependent = what they measured; controlled = held constant
note the ONE thing that differs between experiments - questions live there
'why did they X?' answers are almost always about controlling a variable or providing a comparison
slot the new value into the measured trend from the closest experiment
Question bank breakdown
10
55
22 easy · 20 medium · 13 hard
Skills covered
Every question in the bank comes with a worked explanation, and most add a per-choice breakdown so you learn why each wrong answer is wrong - not just the key.
Sample question
From the free tier of the ScoreMint ACT Science bank - try it, then check the answer.
In Experiment 1, what was the purpose of keeping the bob mass and displacement angle the same for every trial?
- A. To ensure those factors were the independent variables in the experiment.
- B. To control those variables so that any change in the period could be attributed to differences in string length.
- C. To increase the period so it could be measured more accurately.
- D. To make the pendulum swing faster so more oscillations could be counted.
Show answer and explanation
Answer: B. Correct. By holding mass and angle constant, the students ensured that the only factor varying was string length. Any observed change in period can therefore be attributed to the change in string length rather than to confounding variables.
Study tip
As you skim each experiment, jot a three-word margin note: what changed, what was measured. Cross-experiment questions become table lookups instead of re-reads.