ACT Science — reading real figures: line graphs, bar graphs, scatterplots and a two-axis graph

Interpretation of Data is the largest part of the ACT Science section: ACT describes it as 38 to 50 percent of the questions, and it asks you to read tables, graphs and diagrams, recognize trends, interpolate and extrapolate, and reason with the numbers. The section itself is optional on the enhanced ACT and sits outside the Composite, but if you take it, most of your score depends on reading figures quickly and correctly.

Every question in this material comes with its own drawn figure, the way the real section presents data. You work with six figures, two questions each: a line graph with two solubility curves that cross, a grouped bar graph comparing the germination of two plant species at four temperatures, a scatterplot of tree height against trunk diameter with a best-fit line, three cooling curves for water in metal, glass and foam cups, two bell-shaped enzyme activity curves, and a climate graph that puts a temperature line and precipitation bars on two different vertical axes.

The questions train the moves that cost points under time pressure. You find where two curves cross by noticing where their order flips, and you locate the steepest stretch of a curve by comparing changes over equal intervals. You compare paired bars instead of picking the tallest one. You extend a best-fit line a short distance and separate what a scatterplot shows, a tendency with exceptions, from what it cannot show, a cause. You follow a gridline to the right curve among three, read a half-maximum on both sides of a peak, and keep a two-axis graph straight by reading each series on its own scale. Every explanation shows the reading step by step and names the trap each wrong option sets, such as a value taken from the wrong curve or the wrong axis.

The flashcards review the reading habits behind these questions: axis labels and units first, legends, interpolation and extrapolation, crossings, slopes, trend lines, association and cause, and figures with two vertical axes.

This material offers a quiz and flashcards. It is independent practice based on ACT's public description of the section; the figures and data are original, and nothing here is produced or endorsed by ACT.

• Read values from line graphs, grouped bar graphs, scatterplots and two-axis graphs using the correct axis, unit and legend
• Find where two curves cross and where a curve changes fastest
• Use a best-fit line to make a short prediction and distinguish an association from a cause
• Read a half-maximum or a threshold crossing on the correct curve among several
• Recognize the trap answers built from the wrong curve, the wrong axis or a single value instead of a difference

Practice material written by Zestly, based on ACT's published description of the ACT Science section (reporting categories Interpretation of Data, Scientific Investigation, and Evaluating Scientific Arguments and Models with Evidence; act.org, retrieved September 2026). All data sets, figures and questions are original.