15 scenario-based GED Science questions with full explanations — experimental design, data tables, density calculations, trend analysis, and genetics probability, in the format the real test actually uses.
A free GED science practice test should give you passages, data tables, and experiments rather than vocabulary definitions. The official test is 40% life science, 40% physical science, and 20% Earth and space science, and roughly half its items sit in scenarios where two or three questions share one stimulus. These 15 questions follow that format. You need 145 to pass.
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A free GED science practice test is only worth taking if it practices the right thing. Do not treat GED Science as a list of biology terms to memorise — the test asks you to work with scientific information, interpret graphs and tables, evaluate experiments, reason from evidence, and apply concepts to situations you have never seen. Memorising definitions is the most common way people over-prepare and still miss the score.
The official Assessment Guide for Educators sets the content split at approximately 40% life science, 40% physical science, and 20% Earth and space science. It also says about half the items come in scenarios. In those, two or three questions share one stimulus.
That structure should change how you practice. A useful free GED science practice test needs passages, experiment setups, data tables, calculations, and questions that make you back an answer with evidence. The 15 questions below are original. They follow the reasoning the current framework describes.
Work each question before reading its explanation. If you want the wider strategy first, the how to pass the GED science test guide covers the chart-reading approach behind most of these items.
What Does the GED Science Test Actually Measure?
Science questions are built on three content domains with fixed weights. The Assessment Guide states these directly rather than leaving them to interpretation:
Content domain
Approximate share
Life science
40%
Physical science
40%
Earth and space science
20%
On top of that sit the science practices. These are reading science presentations, designing and judging investigations, reasoning from data, judging conclusions, working with findings, applying theories and formulas, and using probability and statistics. Those practices are what the reporting categories actually score:
Reporting category
Weight
Analyzing scientific and technical arguments, evidence and text-based information
30%
Applying scientific processes and procedural concepts
40%
Reasoning quantitatively and interpreting data in scientific contexts
30%
Read those two tables together and the strategy is clear. Content knowledge decides which domain a question is dressed in. The reporting categories decide what you are graded on. A question can hand you information you have never seen and still expect an answer. The stimulus gives you the details. Your job is to work out what they show.
Free GED Science Practice Questions
These questions use multi-step scenarios on purpose. Two or three share one setup, just like the real test. Try each one before you read the explanation.
Questions 1–3: Experiment Design and Data
A researcher investigates whether fertiliser concentration affects the growth of bean plants. Four groups contain 20 plants each. Every group receives the same amount of water and sunlight.
Group
Fertiliser concentration
Average height after 30 days
A
0%
18 cm
B
2%
24 cm
C
4%
31 cm
D
8%
22 cm
Question 1
What is the dependent variable in this investigation?
A. Fertiliser concentration
B. Number of plants
C. Average plant height
D. Amount of sunlight
Answer: C
The researcher changes fertiliser concentration and measures what happens to growth. The variable being measured is the dependent one, so average plant height is the answer. Fertiliser concentration is the independent variable; water and sunlight are controlled.
Question 2
Which conclusion is best supported by the results?
A. Increasing fertiliser concentration always increases plant growth.
B. A 4% concentration produced the greatest average height among the groups tested.
C. Fertiliser has no measurable effect on plant growth.
D. The 8% concentration was more effective than the 4% concentration.
Answer: B
The 4% group reached 31 cm, the highest average in the experiment. Option A fails because the 8% group averaged only 22 cm — growth fell once concentration passed 4%. This is the most common GED Science trap. The wrong answer sounds like a general rule. The data only supports a statement about the groups actually tested.
Question 3
The researcher wants to determine whether the 4% concentration consistently produces the greatest growth. Which change would strengthen the investigation?
A. Test more plants at each concentration and repeat the experiment.
B. Remove the control group from the experiment.
C. Give each group a different amount of sunlight.
D. Change fertiliser concentration during the experiment.
Answer: A
Repeating with a larger sample produces more observations and reduces the influence of unusual results. The other three all break the experiment. Removing the control destroys the baseline. Varying sunlight adds a second thing that changed, so you cannot tell which one mattered. Changing concentration part-way means you no longer know what caused the result.
Questions 4–6: Life Science and Body Systems
During exercise, muscle cells need more energy. A researcher measures oxygen consumption in a participant at increasing exercise intensity.
Exercise intensity
Oxygen consumption
Rest
0.3 L/min
Light
0.8 L/min
Moderate
1.6 L/min
Vigorous
2.9 L/min
Question 4
Which process most directly explains why oxygen consumption increases as exercise intensity increases?
A. Cellular respiration increases energy production in active cells.
B. DNA replication stops in active muscle cells.
C. Digestion completely stops during exercise.
D. Muscle cells stop using nutrients for energy.
Answer: A
Active muscles need more usable energy, and cellular respiration uses oxygen to release energy from nutrients. More demand for energy means more oxygen consumed. Options B, C and D all describe processes stopping, which would reduce rather than explain increased oxygen use.
Question 5
A second participant has an oxygen consumption of 2.1 L/min during vigorous exercise. Which conclusion is justified?
A. The second participant definitely has a disease.
B. The second participant used no oxygen during exercise.
C. The second participant had lower measured oxygen consumption under that condition.
D. The second participant produced more energy than the first participant.
Answer: C
The data supports only the measured difference: 2.1 L/min is lower than 2.9 L/min. It does not diagnose a condition, and it does not establish total energy production. Questions like this reward the smallest claim the evidence actually carries, which almost always looks like the least impressive option on the list.
Question 6
Which additional measurement would help researchers determine whether fitness level influences the results?
A. Participants’ shoe sizes
B. Participants’ fitness levels
C. The room’s wall color
D. The brand of stopwatch
Answer: B
If you want to know whether a variable influences an outcome, you have to measure that variable. Fitness level plausibly affects how the body responds to exercise. Shoe size, wall color and stopwatch brand do not.
Questions 7–9: Physical Science and Quantitative Reasoning
A technician measures the density of four metal samples, where density = mass ÷ volume.
Sample
Mass
Volume
A
54 g
20 cm³
B
72 g
24 cm³
C
90 g
30 cm³
D
105 g
35 cm³
Question 7
Which sample has a density different from the other three?
A. Sample A
B. Sample B
C. Sample C
D. Sample D
Answer: A
Calculate all four before comparing:
A: 54 ÷ 20 = 2.7 g/cm³
B: 72 ÷ 24 = 3.0 g/cm³
C: 90 ÷ 30 = 3.0 g/cm³
D: 105 ÷ 35 = 3.0 g/cm³
Samples B, C and D all come out at 3.0 g/cm³, even though their masses and volumes differ. That is the point worth keeping. Density is a ratio, so it tells you what a thing is made of, not how much of it you have. Only Sample A differs, at 2.7 g/cm³.
Question 8
A 120 g metal sample occupies 40 cm³. What is its density?
A. 2 g/cm³
B. 3 g/cm³
C. 4 g/cm³
D. 4.8 g/cm³
Answer: B
Density = mass ÷ volume, so 120 ÷ 40 = 3 g/cm³. Note that this matches samples B, C and D above — the same material at a different size.
Question 9
A technician measures another sample with a mass of 180 g and a density of 6 g/cm³. What is its volume?
A. 20 cm³
B. 30 cm³
C. 60 cm³
D. 1,080 cm³
Answer: B
Rearrange the relationship: volume = mass ÷ density, so 180 ÷ 6 = 30 cm³.
Option D is what you get by multiplying instead of dividing. Recognizing which quantity is missing and rearranging the formula matters more than memorising the formula in one direction, and the GED tests it in exactly this way.
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Questions 10–12: Earth Science and Data Interpretation
Scientists monitor the concentration of dissolved oxygen in a lake at different water temperatures.
Water temperature
Dissolved oxygen
10°C
11.3 mg/L
15°C
10.1 mg/L
20°C
9.0 mg/L
25°C
8.2 mg/L
30°C
7.4 mg/L
Question 10
Which relationship is supported by the data?
A. Dissolved oxygen increases as temperature increases.
B. Dissolved oxygen decreases as temperature increases.
C. Temperature has no relationship with dissolved oxygen.
D. Dissolved oxygen remains constant.
Answer: B
Dissolved oxygen falls steadily from 11.3 mg/L at 10°C to 7.4 mg/L at 30°C. Every step down the table confirms the same direction, which is what makes the relationship well supported rather than merely suggested.
Question 11
Based on the trend, which dissolved oxygen concentration would be most reasonable to expect at 35°C?
A. 5–8 mg/L
B. 10–13 mg/L
C. 15–18 mg/L
D. 20–23 mg/L
Answer: A
Values decline as temperature rises, and the last measured point is 7.4 mg/L at 30°C. Extending the trend one step further puts the expected value below 7.4, so the 5–8 mg/L band is the only reasonable option. The other three all require the trend to reverse.
Question 12
A researcher claims that warmer water always contains more dissolved oxygen. Which evidence most directly challenges the claim?
A. Dissolved oxygen decreased from 11.3 mg/L to 7.4 mg/L as temperature increased.
B. The lake was measured at five different temperatures.
C. The lowest temperature recorded was 10°C.
D. The measurements were recorded in milligrams per litre.
Answer: A
The claim predicts an increase; the data shows a decrease. Options B, C and D are all true statements about the study. But describing how an experiment was run is not evidence against its conclusion. "Most directly challenges" means the option that contradicts the claim, not the one that sounds most scientific.
Questions 13–15: Genetics, Probability and Evidence
A plant has two alleles for seed color. Yellow seeds are represented by Y and green seeds by y. Two plants with genotype Yy are crossed.
Question 13
What percentage of offspring are expected to have the genotype yy?
A. 0%
B. 25%
C. 50%
D. 75%
Answer: B
The four possible combinations from a Yy × Yy cross are YY, Yy, Yy and yy. One of the four is yy, so 1 ÷ 4 = 25%.
Question 14
If yellow is dominant, what percentage of offspring are expected to have yellow seeds?
A. 25%
B. 50%
C. 75%
D. 100%
Answer: C
Three of the four combinations — YY, Yy and Yy — contain at least one dominant Y allele, so 3 ÷ 4 = 75%. Note the distinction the question depends on: genotype yy is 25%, but the yellow phenotype is 75%, because one dominant allele is enough to express it.
Question 15
A researcher produces 100 offspring and observes 68 yellow-seeded and 32 green-seeded plants. Which statement best evaluates the result?
A. The result proves that the genetic model is false.
B. The result is reasonably close to the predicted 75% yellow and 25% green distribution.
C. The result proves every offspring must have the same genotype.
D. The result shows that green is dominant.
Answer: B
The prediction is roughly 75 yellow and 25 green. Observing 68 and 32 differs from that. Real results do not have to match predicted odds exactly, and chance variation in a sample of 100 easily explains the gap. Treating any gap as disproof is the error this question is built to catch.
Before you read the breakdown below, go back and mark which questions you got right for the wrong reason. Those matter more than the ones you missed outright.
What These GED Science Questions Are Testing
The skill that matters is never the answer to one question. Each set above pairs science content with a reasoning task. That is how the real test is built:
Data interpretation and the limits of what a measurement justifies
7–9
Physical science
Quantitative reasoning — applying and rearranging a formula
10–12
Earth science
Identifying a trend, extending it, and evaluating a claim against it
13–15
Genetics
Probability and evaluating observed results against a prediction
That pairing is why strong GED science practice questions should not consist only of definitions such as "what is photosynthesis?". A stronger question hands you an experiment and asks what the results demonstrate. Notice how often the right answer above was the most cautious one. The GED keeps rewarding the smallest claim the evidence supports.
How to Use Your GED Science Practice Results
Count your mistakes by skill, not by total. Six misses spread across five skills is a very different problem from six misses all in data reading. Your total score cannot tell those apart, which is why it is the least useful number on the page.
Pattern in your mistakes
What to practice
Graphs and tables
Trends, comparisons and predictions
Experiments
Variables, controls and sources of error
Calculations
Units, formulas and rearranging relationships
Biology
Cells, body systems, heredity and ecosystems
Earth science
Systems, cycles and evidence
Conclusions
Separating evidence from unsupported claims
About 60% of Science items sit at Depth of Knowledge level 2 or 3. About half come in scenarios tied to one stimulus. Both facts point the same way. Do not rush a worksheet to raise your question count. Read the stimulus, find the evidence, and be able to say why the answer follows from it.
How to Use GED Science Worksheets
Good GED science worksheets should recreate the reasoning process the test uses. A useful worksheet gives you one experiment followed by several questions rather than ten unrelated vocabulary items, because that is the format roughly half the real test takes.
After each session, record the exact reason for every mistake. "I got question 8 wrong" is useless. "I divided the wrong quantities when solving for volume" tells you precisely what to drill. Mix standalone questions with scenario sets, since the official test uses both in roughly equal measure. Twigera’s free printable GED worksheets are built around that mix rather than around question count.
One more habit is worth building. Work the stimulus before you read the questions. Note what changed, what was measured, and what stayed the same. Most scenario sets ask about those three things in some form, so five seconds spent on the setup usually pays for itself twice.
What About GED Science 200 Questions?
Searches for large question banks usually reflect a reasonable instinct — more practice should mean more preparation. It does not follow automatically. A 200-question collection that recycles basic definitions gives you less useful practice than 30 carefully designed items covering experiment design, graphs, probability, formulas, scientific claims and multi-step reasoning.
The order matters more than the volume, and most people get it backwards. Start with diagnostic practice to find the weak skill, drill that skill specifically, then return to mixed questions to confirm it holds under unfamiliar scenarios. Large banks earn their place at the third stage. Use them at the first stage and you mostly get a long list of results you cannot read. That is how people practice for weeks and see no score movement. Ten questions you can explain beat a hundred you merely finished.
How Is GED Science Scored?
Every GED subject is reported on a 100 to 200 scale, and 145 passes. Scores of 165 to 174 earn College Ready and 175 to 200 earn College Ready + Credit. GED Testing Service publishes the full score scale and performance levels for all four subjects.
There is no fixed number of questions you can miss. The GED reports a scaled score rather than a raw count, so no published table converts correct answers into a 145.
Your Science score reflects performance across the whole test, not a straight percentage of items you got right. Item difficulty feeds into the scaling. That is exactly why practice results work best as a skill check. Miss data questions again and again, and the fix is reading graphs and tables. If the calculations are the problem, work number-based science problems until rearranging a formula is automatic. For the wider subject picture, see what subjects are on the GED test.
What to Do Next
Review every wrong answer and every question you guessed correctly, then group the mistakes by skill rather than by topic. Graph misses mean practicing trends and predictions. Experiment misses mean variables and controls. Calculation misses mean units and rearranging formulas. Conclusion misses mean separating evidence from unsupported claims.
Then take a different set of questions rather than repeating this one. Retaking a test you have already seen measures your memory of these items, not your science reasoning. Fresh questions are the only honest check. Give it a few days first, so you are testing the skill rather than the memory. If math is also on your list, the free GED math practice test follows the same diagnose-then-target structure, and how to study for the GED covers sequencing all four subjects.
Frequently asked
Questions people ask.
What kind of questions are on the GED Science test?
ShowHide
Scientific passages, graphs, tables, diagrams, experiments, calculations, probability, and evidence evaluation. GED Testing Service currently lists multiple choice plus fill in the blank, drag and drop, select an area, and drop down. Short answer items were discontinued from the Science test in early 2018, so ignore older guides that still list them. Roughly half the items appear in scenarios where two or three questions share a single stimulus.
Do I need to memorise science facts for the GED?
ShowHide
Less than most people assume. You need familiarity with major concepts, but the Assessment Guide states that stimuli supply the necessary details about graphics, formulas, and key principles. The test measures whether you can reason from information in front of you. Memorising definitions without practicing data interpretation is the most common way people over-prepare and still miss the score.
What is on the GED Science test?
ShowHide
Three content domains with fixed weights: approximately 40% life science, 40% physical science, and 20% Earth and space science. Layered on top are the science practices — reading scientific presentations, designing and evaluating investigations, reasoning from data, evaluating conclusions, applying theories and formulas, and using probability and statistics.
How is the GED Science test scored?
ShowHide
On the same 100 to 200 scale as every GED subject, with 145 required to pass. Your score reflects performance across the assessment rather than a raw percentage of questions answered correctly, because item difficulty feeds into the scaling. That is why a practice-test percentage is best treated as a skill diagnostic rather than a score prediction.
Is a GED science practice test useful?
ShowHide
Only if you analyze the mistakes. A practice test shows whether your real problem is scientific reading, experimental design, data interpretation, quantitative reasoning, or content knowledge — four very different fixes. Counting your score and moving on wastes the diagnostic value, which is the only thing a practice test reliably provides.
Are 200-question GED science banks worth using?
ShowHide
Not as a starting point. A 200-question set that repeats basic definitions gives you less useful practice than 30 well-designed items covering experimental design, graphs, probability, formulas, and multi-step reasoning. Use large banks for repetition after a diagnostic has identified a specific weak skill, not as the diagnostic itself.
How hard is the GED Science test?
ShowHide
Approximately 60% of items sit at Depth of Knowledge level 2 or 3, meaning most questions require more than recalling a fact. The difficulty is rarely the science content itself — it is being asked to draw a conclusion from data you have never seen before and to distinguish what the evidence supports from what merely sounds plausible.
What should I do after taking a GED science practice test?
ShowHide
Review every wrong answer and every question you guessed correctly, then group the mistakes by skill rather than by topic. Graph misses mean practice trends and predictions. Experiment misses mean variables and controls. Calculation misses mean units and rearranging formulas. Conclusion misses mean separating evidence from unsupported claims. Study the weakest group, then take a different set.
Amara is the editor at Twigera. She came to publishing the long way — a decade teaching the GED in community colleges and adult-learning centers, where she watched students pass not on talent or time, but on the strength of a study plan they actually trusted. Now she shapes the guides students read here for the parent studying after a closing shift, the second-career welder, the grandmother finishing what she started forty years ago. Expect honest timelines, math made survivable, and study plans built around real life — not around a textbook's idea of one.
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