GED Science Study Guide: Experiments, Graphs, and Evidence

What the 90 minutes are for

GED.com’s science page lists three jobs: reading for meaning in science, designing and interpreting experiments, and using numbers and graphics. The 90 minutes include 2 minutes of instructions and final review. There is no scheduled break. An on-screen calculator is listed. A physical calculator is a test-center question, not an online one. Those rules are on the calculator page.

The page also says you do not need to memorize formulas. If a formula is required, the item provides it. This guide will not dump a list of biology terms to memorize.

An original experiment

This setup is made up for practice.

A student tests whether a lid changes how fast a wet sponge dries. Two identical sponges start at 50 grams. Both sit in the same room. Sponge A is uncovered. Sponge B is in a closed plastic box. After 24 hours, A weighs 32 grams and B weighs 46 grams.

• Independent variable: covered versus uncovered. That is what the student changed.
• Dependent variable: the mass after 24 hours. That is what was measured.
• Controls: starting mass, the room, and the 24-hour wait.
• Supported conclusion: in this trial, the uncovered sponge lost more mass (18 grams) than the covered sponge (4 grams).
• Unsupported conclusion: every sponge in every room will dry this way, or the box “stopped evaporation” as a proven mechanism. The data show a mass difference. They do not name the mechanism unless the item gives it.

Losing 18 grams versus 4 grams is arithmetic from the table: 50 − 32 = 18 and 50 − 46 = 4. The science skill is knowing which subtraction answers the question.

A graph check

A made-up line for one plant lists height as 2 cm on day 1, 3 cm on day 4, and 3 cm on day 7. The supported statement is that the recorded height rose from day 1 to day 4 and did not change between day 4 and day 7. An unsupported statement is that the plant died, or that it will be 4 cm on day 10. Flat data are still data. A future day was not measured.

Practice another original data item → when you can name the variables without looking back. Social studies uses graphs too, but the source is civic or historical rather than an experiment. That skill is on the social studies guide. Science at 145 still leaves the other subjects to pass on their own.