Note on the 2026 ACT: The ACT has made a significant change to the Science section. In the older format, Science was required, and its 40 questions counted toward your composite score. In the current format, Science is optional, contains 40 questions, and is reported separately from your composite score. Colleges decide whether they require, recommend, or consider this score for admissions. Incublia offers full-length practice tests with or without Science, so you can be fully prepared for test day.

For big-picture test strategy, see our ACT strategy guide and Enhanced ACT overview. For score goals, use our ACT score guide.

The most consistent advice from every source is that ACT Science is actually a reading and logic test. You do not need advanced scientific knowledge to do well. The test primarily measures your ability to find specific details in graphs and text.

That said, a small number of questions require outside knowledge of basic science concepts, things like pH 7 being neutral or gravity being a downward force. Section 3 of this guide covers exactly what you need to know.

• The “answer is on the page” mantra:The majority of the Science questions can be answered by looking only at the charts and graphs. You often don't even need to read the introductory text.
• Time management is critical:You have 40 minutes for 40 questions, with 34 questions scored and 6 unscored field test items embedded throughout. You won't know which questions count, so treat every question as if it matters.
• If you get stuck on a hard question, guess and move on. Do not sacrifice easy questions at the end of the test for one hard question in the middle.
• Order of passages: You do not have to do the passages in order.
• Scan first: Quickly flip through the test. Do the passages with the simplest-looking graphs first.
• The “now, later, never” method:Immediately answer questions with clear locators (e.g. “In Figure 1…”). Save questions that require fully reading the passage for last.

There are three specific types of passages, and you should treat them differently.

A. Data representation (charts & graphs)

• What it is: 5–7 questions. Heavy on visuals, light on text.
• Strategy:Don't read the passage first. Go straight to Question 1.
• Tactic:Read the question, find the “locator” (e.g. “Figure 2”), and go directly to that figure to find the answer. Only skim the text if a question asks for a definition or concept not in the graph.

B. Research summaries (experiments)

• What it is: 5–7 questions. Describes an experiment (Student 1 did X, Student 2 did Y).
• Strategy:Don't read the passage first.
• Tactic: Focus on the differences between experiments. Did the temperature change? Did the amount of water change?
• Key concept: Identify the independent variable (what they changed) and the dependent variable (what they measured).

C. Conflicting viewpoints (the “fighting scientists”)

• What it is: 5–7 questions. No graphs (usually). Two or more scientists arguing about a theory.
• Strategy: Read the whole passage first. This is the only time you should read before answering.
• Tactic:As you read, annotate. Write a 3–4 word summary next to each scientist's paragraph (e.g. “Scientist A: Asteroid caused extinction” vs. “Scientist B: Volcano caused extinction”).
• Timing tip: Many students save this passage for last because it takes the most time to read. However, if you are a strong reader but weak at reading graphs, you might consider doing this first.

While most answers are in the text, about 3–4 questions per test require outside knowledge. Here is the cheat sheet of concepts that frequently appear:

Biology

Cell parts

• Mitochondria: Makes energy (ATP).
• Chloroplasts: Photosynthesis (plants only).
• Ribosomes: Make proteins.
• Nucleus: DNA storage.

• Genetics: Alleles (traits). Capital letters (T) are usually dominant; lowercase (t) are recessive.
• Photosynthesis: Plants use sunlight + CO₂ + water → sugar + oxygen.

Chemistry

• pH scale: 7 is neutral (water). Below 7 is acidic. Above 7 is basic.
• Density: Formula = mass / volume. Denser things sink; less dense things float.
• Phase changes: Solid → liquid (melting) → gas (boiling). Freezing point of water = 0°C; boiling point = 100°C.
• Charges: Opposites attract (+ and −); likes repel (+ and +).

Physics

• Gravity: A downward force.
• Energy: Kinetic = moving energy; potential = stored energy (height or stretched spring).

• Draw on the graphs:If a question asks for a value outside the graph's range, you need to extrapolate to see where the line would go if it continued. On the digital ACT, use the zoom functionality for a closer look at the graph, or hold your scratch paper up to the screen as a straight edge to help track the line. On the paper test, use your pencil to extend the line.
• Use process of elimination: If you have to guess, eliminate answers that are scientifically impossible or directly contradicted by the graph. On the digital ACT, use the built-in Answer Eliminator tool to cross out wrong answers on screen. On the paper test, cross them out in your test booklet.
• Pay attention to labels: The most common mistake is misreading an axis (for example, reading the left Y-axis instead of the right Y-axis). Make sure to reread the question and confirm which axis you should be looking at.
• The locators:Identify words in the question that tell you where to go (for example, “Experiment 1,” “Table 2”). On the digital ACT, use the Highlighter tool to mark locators as you read each question. If a question doesn't tell you where to look, the answer is usually in the intro text.