Science
What the Science test covers
The GED Science domain tests life science, physical science, and earth and space science through scientific practices. Use the current official instructions for actual timing and task counts. Many questions ask you to read a graph, table, or short experiment description, identify variables, evaluate a conclusion, or apply a scientific principle. Check current official instructions for permitted tools in the actual assessment. The emphasis is on reasoning with evidence, not on memorizing every fact.
Core rules and concepts
- Experiment design: the independent variable is what the researcher changes; the dependent variable is what is measured; the control group receives no treatment or a standard treatment; constants are kept the same for all groups.
- Reliability and validity: larger samples and repeated trials increase confidence; a well-designed experiment has a control and controls confounding variables.
- Data interpretation: read the axes, units, legend, and scale before choosing an answer. Correlation does not establish causation.
- Life science: cells, photosynthesis and respiration, DNA and inheritance, natural selection, ecosystems, and energy flow.
- Physical science: Newton’s laws, speed and acceleration, energy transfer, waves, electric circuits, chemical reactions, and conservation of mass.
- Earth and space science: plate tectonics, the rock cycle, weather and climate, the water cycle, and the solar system.
Worked example
A student wants to test whether a fertilizer increases plant height. She gives Group A fertilizer and Group B no fertilizer. Both groups get the same amount of water, light, soil, and pot size. After four weeks, Group A is taller on average. The independent variable is the fertilizer treatment; the dependent variable is plant height. Group B is the control group. Water, light, soil, and pot size are constants. Because those factors are controlled, the result supports the hypothesis that fertilizer increased height-but only for this experiment. Before generalizing, the student should repeat the trial and use a larger sample.
Traps that cost marks
- Swapping the independent and dependent variables.
- Ignoring the control group or assuming any difference proves the treatment worked.
- Reading a graph without checking units or whether the y-axis starts at zero.
- Treating a small or unreplicated result as conclusive.
- Confusing correlation with causation, especially in observational data.