On the GED Science test, many questions ask you to judge an experiment: what was changed, what was measured, what stayed the same, and whether the results back up a claim. This free lab gives you nine original experiments to practice exactly that, one step at a time, with feedback on every answer.
What the lab practices
Step 1: sort six cards into independent variable, dependent variable, controlled variables and control group (drag and drop or a menu for each card).
Step 2: choose the testable if/then hypothesis, or write your own and check it against a short checklist.
Step 3: select the sentence that weakens a flawed design and name the flaw: more than one variable changed, no control group, sample too small, no repeated trials, biased sampling or assignment.
Step 4: read a results table and decide whether each claim is supported, contradicted or cannot be told from the data.
Practice mode gives feedback after each step; Test style holds feedback until you submit all four steps.
Key terms
Independent variable: The one condition the investigator changes on purpose. Example: Whether seedlings get fertilizer.
Dependent variable: The outcome that is measured. It may change because of the independent variable. Example: How much each seedling grew, in centimeters.
Controlled variables: Conditions kept the same for every group, so they cannot explain the result. Example: Water, soil and hours of light.
Control group: The group that gives a baseline. It often gets no treatment, or the usual one. Example: Seedlings that get no fertilizer.
Hypothesis: A testable prediction, often written "If ..., then ...". Example: If seedlings get fertilizer, then they will grow more than seedlings without it.
The 9 practice experiments
All scenarios and data are invented for practice.
Fertilizer and bean seedlings (Life science): Does adding fertilizer change how much bean seedlings grow in three weeks?
Keeping water warm (Physical science): Does wrapping a cup change how much heat the water inside loses?
Sugar and yeast (Life science): Does the amount of sugar change how much gas yeast makes?
Salt and melting ice (Physical science): Does sprinkling salt on ice change how fast it melts?
Grass and soil erosion (Earth and space science): Does grass growing on soil reduce how much soil water washes away?
Soaking seeds before planting (Life science): Does soaking pea seeds overnight change how soon they sprout?
Color and solar heating (Physical science): Does the color of a can change how much the water inside warms in sunlight?
A homemade water filter (Earth and space science): Does adding charcoal to a sand filter make muddy water clearer?
Temperature and bread mold (Life science): Does storage temperature change how soon mold appears on bread?
Official GED Science facts (checked 2026-10-26)
The GED Science test takes 90 minutes, including 2 minutes of instructions and final review, with no break (GED.com test subjects page).
Science uses multiple choice and other question types: fill in the blank, drag and drop, select an area and drop down (GED.com).
The official Science topic areas are Reading for Meaning in Science, Designing and Interpreting Science Experiments, and Using Numbers and Graphics in Science (GED.com).
About 40 percent of the test is life science, 40 percent physical science and 20 percent Earth and space science (GED Assessment Guide for Educators, Science).
GED.com says you do not need to memorize formulas for Science; the information you need is provided.
The passing score is 145 in each subject, on a 100 to 200 scale (GED.com scores page).
What to do next
Work through the lab in Test style until you get each part right on the first check.
Read GEDPilot lesson GP-S01, Read the Evidence and Test the Claim, in the book or online in the library (/library/GP-S01, included with the book or a plan).
Take the free GEDPilot diagnostic (/tests) to see which subject needs you most.
Before you book Science, take GED Ready, the official practice test, and aim for the green Likely to Pass band (145 to 200).
You can schedule one subject at a time, so Science can be its own test day when you are ready.
What is the difference between the independent and dependent variable? The independent variable is the condition the investigator changes on purpose. The dependent variable is the outcome that gets measured. A quick test: put them in the sentence "If I change the independent variable, then I measure the dependent variable." If the sentence makes sense, you have them the right way around.
Is a control group the same as a controlled variable? No. Controlled variables are conditions kept the same for every group, like water or temperature. A control group is a whole group used as the baseline for comparison, such as plants that get no fertilizer or bread kept at the usual room temperature.
How do I write a hypothesis for a GED Science question? Use "If [the change you make], then [the result you expect to measure]." Name the independent variable in the "if" part and the dependent variable in the "then" part, and say which way you expect it to go: more, less, faster or slower. Avoid opinions such as "best".
What design flaws do GED Science questions ask about? Common ones are: more than one variable changed; no control group; sample too small; no repeated trials; biased sampling or assignment. For each, ask what other explanation the flaw allows, then pick the change that removes it.
Are experiment questions really on the GED Science test? Yes. Designing and Interpreting Science Experiments is one of the three official Science topic areas on GED.com. The educator guide lists skills such as identifying independent and dependent variables and judging whether data support a conclusion.
How do I know if data support a conclusion? Check three things. Do the numbers point the same way as the claim? Does the claim stay inside what was tested (the same organisms, amounts and conditions)? And does it avoid words like "always", "every" or "proves" that go further than one study can? If the data say nothing about the claim, the answer is "cannot tell".
Are these real GED test questions? No. Every scenario and data table in this lab is original practice material with invented numbers. The skills match the official Science topic areas, but GEDPilot is independent and not affiliated with GED Testing Service.
Independent preparation materials. Not affiliated with or endorsed by ACE or GED Testing Service. GED is a registered trademark owned by ACE. Practice results do not predict an official GED score, and GEDPilot does not guarantee a passing score.