ACT Science (ACT, Inc.): the optional reasoning section, the three passage formats, the reporting categories, and how to study for a high score

The ACT Science section is the reasoning section of the ACT, produced by ACT, Inc. As of the enhanced ACT rolled out in 2025, Science is optional: it is scored on the 1 to 36 scale and feeds the STEM score (Science combined with Math), but it no longer counts toward the Composite, which is now the average of English, Math, and Reading only. This page is the index: below is a map of the section, the three passage formats, the reporting categories, and how to study each skill for a high score.

This library covers ACT Science in full: a format and strategy module that explains the optional status, the scoring, and who should take it, plus one module each for interpreting data, research summaries and experimental design, conflicting viewpoints, the underlying scientific reasoning skills, and pacing across the three passage types.

The section at a glance

The enhanced ACT Science section is 40 questions in 40 minutes. The legacy section was the same 40 questions but in 35 minutes, and it counted toward the Composite. Either way, the section is built from short scientific passages, almost always paired with figures (graphs, tables, and diagrams).

• Format: several passages, each followed by a set of questions, for 40 questions in total.
• Scoring: reported 1 to 36 when taken; optional on the enhanced ACT; feeds the STEM score, not the Composite.
• Calculator: not provided or needed; the arithmetic is light and the data are on the page.
• Content: drawn from biology, chemistry, physics, and Earth and space science, but no advanced knowledge is required.

The single most important fact about this section is that it tests science reasoning, not content recall. You are not asked to remember the products of a reaction or the stages of mitosis. You are asked to read a figure, follow an experiment, and judge a conclusion, using the information given to you on the page.

The three passage formats

Every ACT Science passage uses one of three formats, and recognising the format tells you how to attack it.

Data Representation (about 30% of the section)

Graphs, tables, and diagrams, much like a figure lifted from a science journal, with a few lines of introduction. The questions ask you to read values, identify trends, interpolate and extrapolate, and translate between a table and a graph. These are the most figure-driven passages and usually the fastest to score on.

Research Summaries (about half of the section)

Descriptions of one or more related experiments, with their methods and results, often as a table of data for each study. The questions focus on experimental design (variables, controls, what was held constant) and on comparing and extending the experiments, including predicting the result of a new trial. This is the largest format.

Conflicting Viewpoints (about 15% to 20% of the section)

Two or more competing explanations of the same phenomenon, written as short arguments (for example, Scientist 1 versus Scientist 2, or Hypothesis A versus Hypothesis B). The questions ask you to understand, compare, and evaluate each view. This is the most reading-heavy and least figure-heavy format.

At least one passage on the enhanced ACT is an engineering and design scenario, applying scientific reasoning to a practical design problem.

The three reporting categories

Independently of the passage format, every question is sorted into one of three reporting categories, which are reported back to you as subscores.

Interpretation of Data (the largest share)

Reading and manipulating data presented in tables, graphs, and diagrams: recognising trends, reading exact values, interpolating and extrapolating, and translating information from one form to another.

Scientific Investigation

Understanding experimental tools, procedures, and design: identifying the variables and controls, understanding why a step was taken, and predicting how a change to the method would change the results.

Evaluation of Models, Inferences, and Experimental Results

Judging the validity of scientific information and drawing sound conclusions: deciding which explanation the data support, whether a hypothesis is consistent with a result, and how a new finding affects a claim.

How to study ACT Science

ACT Science rewards a fast, disciplined way of reading figures and arguments, not last-minute content cramming.

1. Learn to read figures first. The biggest category is Interpretation of Data, so practise reading line graphs, bar charts, scatter plots, and multi-variable tables until finding a value or a trend is automatic. This single skill carries the most points.
2. Master experimental design. For Research Summaries, learn to spot the independent variable, the dependent variable, and the controls in seconds, and to predict the result of a new trial by extending a pattern.
3. Build a viewpoints routine. For Conflicting Viewpoints, learn to annotate each view's central claim and its evidence, then answer agreement, disagreement, and "which view does this support" questions cleanly.
4. Answer from the page. Train yourself to find the answer in the figure or text rather than reaching for memorised facts, and flag the rare question that genuinely needs outside knowledge.
5. Drill pacing. With 40 questions in 40 minutes (35 on the legacy form), about a minute per question, you must choose a passage order and protect time for the reading-heavy passage. Practise with a timer in the format you will sit.

The skills, topic by topic

Each topic has a focused answer page with worked ACT Science style questions and cross-links, plus an overview guide and quiz. Browse the full set at /act/science/syllabus.

• Format and strategy: the format and the optional section, what ACT Science actually tests, the three reporting categories, how ACT Science is scored, who should take ACT Science.
• Interpreting data, graphs, and tables: reading line graphs and trends, reading tables and multi-variable data, interpolation and extrapolation, reading scatter plots and best-fit lines, combining figures and reading units.
• Research summaries and experimental design: anatomy of a Research Summaries passage, variables, controls, and experimental design, comparing experiments and results, predicting the results of new trials, engineering and design passages.
• Conflicting viewpoints: anatomy of a Conflicting Viewpoints passage, tracking each viewpoint's claims, points of agreement and disagreement, using evidence to support or weaken a view, the reading-heavy passage strategy.
• Scientific reasoning skills: Interpretation of Data question types, Scientific Investigation question types, evaluating models and inferences, the outside-knowledge questions, translating between graphs and text.
• Pacing and the three passage types: pacing the 40-minute section, ordering the passages, Data Representation passage strategy, Research Summaries passage strategy, Conflicting Viewpoints passage strategy.

For the official test specifications

ACT, Inc. publishes the description of the Science test, the reporting categories, the enhanced ACT changes, and free official practice on its website at act.org. Always study from the current official description and ACT's own practice tests, because the optional status, the section length, and the question style are ACT-specific and have changed recently.