The words ACT Science never stops to explain.
ACT Science is a reasoning test, not a recall test — but it is written for a reader who already knows what a control group, a gradient, or an inverse relationship is. Miss that vocabulary and a passage you could have reasoned through becomes unreadable. These 8 guides cover the 160 terms that assumption rests on.
Four guides cover the subject matter — biology, chemistry, physics, and earth science. The other four cover how the Science section actually asks about it: reading data and graphs, judging experimental design, weighing models against evidence, and handling measurement and mathematical relationships. Open a topic to read its full word list, or download the PDF and print it.
How to use them
Do not memorize these the way you would English vocabulary. What matters on Science is recognition speed: you need to see independent variable in a question stem and know instantly which axis to look at, without stopping to reason it out. Read a topic, then go straight into a passage that uses it — the terms stick when they are attached to a figure you actually read.
Start with Data & Graphs and Experimental Design if you are short on time; those two carry the most questions regardless of the subject matter in front of you. For the section itself, see the ACT Science guide and the question-type breakdown. For English and Reading vocabulary, the ACT vocabulary list covers 295 more words.