ACT Science Data Representation: how to read the graphs and tables
Data Representation passages on ACT Science give you tables, graphs or diagrams like those in science journals and textbooks, and the questions ask you to read values, spot trends, and interpolate or extrapolate. ACT says this format is 26–32% of the Science section. In ACT's 2025–26 practice test there were two Data Representation passages with five questions each. Most answers are in the figures, so the main skill is reading axes, units and labels carefully, not outside science knowledge.
Where it shows up on the ACT
| Enhanced ACT | |
|---|---|
| Section | Science (optional) |
| Length | 40 questions (34 scored) in 40 minutes, about 60 seconds each |
| Reporting category | Data Representation (one of three passage formats; ACT reports Science scores by skill category, not by format) |
| Share of the section | 26–32% of Science |
| In the Composite | No. Science gets its own 1–36 score and counts toward STEM. |
ACT gives format shares separately from its three reporting categories. In the scored Science questions of ACT's 2025–26 practice test, we counted 2 Data Representation passages, each with 5 questions and 2–4 figures. Source: ACT, Preparing for the ACT 2025–2026, pp. 6–10: what each section covers and its reporting categories.
What the questions ask you to do
- Read a single value from a table or graph.
- Describe a trend: as one variable increases, what happens to the other?
- Interpolate a value between two data points.
- Extrapolate a value beyond the data, assuming the trend continues.
- Compare two figures, or match a table to the graph that shows the same data.
How to read a figure
Check these before you look at the questions about a figure.
| Check | Why it matters |
|---|---|
| Title and caption | Tells you what was measured and under what conditions |
| Axis labels and units | Many wrong choices use the right number with the wrong unit or variable |
| Scale | Gridlines may count by 2, 5 or 10, and some axes are not linear |
| Key or legend | Separates the lines or bars when a graph shows more than one group |
| Direction of the trend | Increases, decreases, levels off, or rises then falls |
| Gaps in the data | Tells you when a question needs interpolation or extrapolation |
Common mistakes
Wrong answer choices are often built around these.
- Reading the wrong line or column. With two or more data sets, check the legend before you read a value.
- Ignoring units. A graph in milliliters and a choice in liters can look like a match when they aren't.
- Calling a trend that levels off a straight line. Look at how much each step changes, not just the direction.
- Extrapolating a pattern that doesn't fit. If the data change by a fixed amount, continue by that amount; if they halve each time, continue halving.
- Using outside knowledge when the figure says otherwise. The answer comes from the data shown.
- Spending too long on the passage text before the questions. Read enough to know what each figure shows, then go to the questions.
3 example questions with answers
Written by Ashore in the style of the enhanced ACT. They aren't official ACT questions. Try each one before you open the answer.
Question 1 · Easy
Table 1: Dissolved oxygen in fresh water at different temperatures Temperature (°C) Dissolved oxygen (mg/L) 5 12.8 10 11.3 15 10.1 20 9.1 25 8.3 According to Table 1, as water temperature increases from 5°C to 25°C, the amount of dissolved oxygen:
- Aincreases only.
- Bdecreases only.
- Cincreases, then decreases.
- Dstays the same.
Show the answer
B. Each value is lower than the one before it, from 12.8 mg/L down to 8.3 mg/L, so dissolved oxygen decreases the whole way. There is no rise anywhere in the table, so both choices that include an increase are wrong.
Question 2 · Medium
Table 2: Average height of bean seedlings after 14 days at different daily light periods Light per day (hours) Average height (cm) 4 6.2 8 9.8 12 13.1 16 14.0 Based on Table 2, the average height of seedlings given 10 hours of light per day would most likely be:
- Fless than 6.2 cm.
- Gbetween 6.2 cm and 9.8 cm.
- Hbetween 9.8 cm and 13.1 cm.
- Jgreater than 14.0 cm.
Show the answer
H. 10 hours falls between 8 hours (9.8 cm) and 12 hours (13.1 cm), and height rises with light across that range, so the value should fall between 9.8 cm and 13.1 cm. The range from 6.2 to 9.8 cm belongs to 4 to 8 hours, and more than 14.0 cm would need more light than the table's highest value.
Question 3 · Hard
Table 3: Sound level measured at different distances from a speaker Distance (m) Sound level (dB) 1 94 2 88 4 82 8 76 If the pattern in Table 3 continues, what would the sound level most likely be at 16 m?
- A38 dB
- B64 dB
- C70 dB
- D73 dB
Show the answer
C. Each time the distance doubles, the sound level drops by 6 dB. Doubling 8 m gives 16 m, so the level should be 76 − 6 = 70 dB. 38 dB halves the level, 64 dB drops it by 12 as if the distance had doubled twice, and 73 dB assumes a smaller drop than the pattern shows.
More ACT Science guides
- Research Summaries passages
- Conflicting Viewpoints passage
- Science timing and tips
- ACT score calculator: questions right in each section to a 1–36 score and Composite.
- SAT vs ACT: which test fits you better.
- All ACT guides and free tools
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Practice test 1
Example
27
Composite
(28 + 26 + 27) ÷ 3
- English28
- Math26
- Reading27
- ScienceOptional, not in the Composite25