ACT Science Content: Reading Data, Experiments, and Conflicting Viewpoints
What this domain tests
ACT Science is not a memorized-content test; it is a reasoning test built on three passage types. Data Representation passages present graphs and tables (often several related figures) and ask you to read trends, compare values, and interpolate or extrapolate. Research Summaries describe one or more experiments with procedures, variables, and results, and ask you to identify controls, independent and dependent variables, and what a changed procedure would do. Conflicting Viewpoints passages present two or three scientists' explanations for the same observation and ask which evidence supports or weakens each position.
Concepts you must command
Know the vocabulary of experimental design: independent variable (what the experimenter changes), dependent variable (what is measured), control group, and constants. Recognize that a hypothesis is a proposed explanation and a prediction is a testable consequence. For conflicting viewpoints, track each scientist's central claim, the evidence each cites, and the assumptions each makes.
Traps
- Confusing correlation with causation, or a trend in data with the explanation for that trend.
- Answering from outside knowledge instead of the passage. If the passage does not say it, it is usually wrong.
- Misreading axes: check units, scales, and whether the y-axis starts at zero.
- Choosing an answer true of one viewpoint when the question asks about another.
- Overlooking "EXCEPT" and "NOT" in the stem.
Rule of thumb
For every question, locate the exact line, table, or figure that answers it before reading choices. Predict the answer, then match.
Worked example: A table shows plant height increasing with light intensity up to 400 units, then flattening. A question asks what height to expect at 600 units. The trend has plateaued, so the best answer is "approximately the same as at 400 units," not a continued linear increase.