ASVAB General Science Practice Test (Free, With Answers)
By [Chris, Certification Exam Content Specialist]([AUTHOR BIO LINK]) · Updated September 2026 · Checked against official ASVAB sources
Free ASVAB General Science practice test with an explanation for every answer. These are original practice questions, not actual ASVAB questions.
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What to do with your results
GS is a recall test, so the useful question is which area you missed, not just how many.
- Read every explanation, including for questions you got right.
- Sort each miss into life science, earth and space science, or physical science.
- Go to the matching section below and rebuild that area first.
|
If you mostly miss… |
Go to |
|
Cells, genetics, the human body, ecology |
Life science facts |
|
Earth’s layers, rocks, weather, atmosphere, planets |
Earth and space science facts |
|
Matter, atoms, forces, energy, heat, electricity |
Physical science facts |
|
Questions where two answers looked right |
Look-alike terms |
Jump to: Format and Timing · What GS Covers · Core Facts · Look-Alike Terms · How to Answer · Score Impact · Study Plan · FAQs
What General Science Is
General Science (GS) is the ASVAB subtest that measures your knowledge of physical and biological sciences. It does not count toward your AFQT, but it can affect which military jobs you qualify for. This page covers the format and timing, the science topics worth knowing, the mistakes that cost points, and how GS fits into your score.
About This Practice Test
What is in it. [N QUESTIONS] original multiple-choice questions with four answer choices each, covering [TOPIC BREAKDOWN, for example “X life science, Y earth and space science, and Z physical science questions”].
How it was written. Every question and explanation is original. The questions were written to match the format of the official General Science samples: short, one-sentence questions with four choices, no reading passage. No real ASVAB items were copied. The official ASVAB program says it does not give actual test questions to third-party prep services, and it warns applicants to beware of websites claiming to have actual questions or to guarantee passing scores (official statement). This site makes no such claims.
What it cannot tell you. The real CAT-ASVAB is adaptive, so the difficulty of each question depends on your earlier answers. This test is fixed. ASVAB scores are standard scores, not percentages, so a practice-test percentage is a different kind of measurement from an official score. Use your result to find weak areas, not to predict your official score.
Try the official samples too. The official General Science sample page has four actual sample questions and is worth a few minutes.
Format and Timing
|
ASVAB version |
GS questions |
Time limit |
|
CAT-ASVAB, no tryout questions |
15 scored |
12 minutes |
|
CAT-ASVAB, with tryout questions |
15 scored + up to 15 tryout |
25 minutes |
|
Paper-and-pencil ASVAB |
25 |
11 minutes |
|
PiCAT (unproctored online) |
Adaptive, no tryout questions |
No time limit on individual subtests |
Source: official ASVAB page What to Expect When You Take the ASVAB.
Some prep sites list different numbers, such as 8 or 10 minutes for the computer version. The current official table lists 15 scored questions and 12 minutes.
GS comes first. The official subtest table lists the subtests in the order they are administered, and General Science is first. That makes it your warm-up, so settle in and do not let a hard question early on rattle you.
Tryout questions are new, unscored questions. Each examinee gets them in 2 to 4 subtests, mixed in randomly, with extra time provided. You cannot tell which they are, so treat every question as if it counts.
Average time per question
These figures are our own arithmetic from the official limits:
|
Version |
Calculation |
Average per question |
|
CAT-ASVAB (no tryouts) |
12 min ÷ 15 |
48 seconds |
|
Paper-and-pencil |
11 min ÷ 25 |
about 26 seconds |
GS questions are short, with no passage to read, so the pace is about recall, not reading time. Either you know it or you eliminate and move on. Practice at the pace of the version you expect to take.
CAT-ASVAB rules that change how you answer
- It is adaptive. The test uses your answers to choose the next question. Typically a wrong answer leads to an easier question and a correct answer to a harder one, so a hard question is not a sign you are doing badly.
- You cannot go back. Once you submit an answer, you cannot review or change it.
- Unfinished subtests are penalized. Unanswered questions are scored as if guessed at random. The official guidance is to read and answer legitimately if time is short, because the CAT applies a relatively large penalty when several wrong answers come near the end of a subtest (Preparing for the ASVAB). The official program also says almost all examinees finish each subtest before time expires.
Paper-and-pencil rules
- You can skip a question and return to it within the subtest, and you can review your answers before the subtest ends.
- Unanswered questions count as incorrect, and there is no penalty for guessing, so answer every question.
No calculator is allowed on any version. Scores on the two versions are statistically linked, so you should get a similar score either way (FAQs).
What General Science Covers
The official ASVAB description of GS is “knowledge of physical and biological sciences,” and it falls in the Science/Technical domain (ASVAB Subtests). The official pages do not publish a topic list or say how many questions come from each area.
What they do show is the format. The four official sample questions are single sentences that ask about, in order: why air is less dense than water, a Celsius-to-Fahrenheit equivalent, why salt helps melt ice, and the main gas in Earth’s atmosphere. So GS mixes physical science, chemistry, and earth science in short recall questions, and some ask for the reason behind a fact.
Because of that, we organize study into three areas: life science, earth and space science, and physical science. This grouping is our own study framework, not official ASVAB terminology. The official program also notes that a solid base of core English, math, and science courses helps with GS and the other academic subtests (Preparing for the ASVAB).
Core Facts to Know
Use these tables as a checklist of the basic ideas that short science questions are built from. If a row looks unfamiliar, that is your study list. Rows with a source link are backed by the linked NASA, NOAA, USGS, National Park Service, or NIH page; the other rows are standard introductory science.
Life science
|
Topic |
Know this |
|
Cells |
All living things are made of cells. The nucleus holds DNA and directs the cell. Mitochondria release energy for the cell. Ribosomes build proteins. The cell membrane controls what enters and leaves. Plant cells also have a cell wall and chloroplasts; animal cells have neither. |
|
Photosynthesis and respiration |
Photosynthesis: carbon dioxide + water + light energy → glucose + oxygen. Cellular respiration uses oxygen and glucose to make energy-carrier molecules (ATP) and releases carbon dioxide. (Nature Scitable) |
|
Genetics |
DNA carries genetic information in genes. Humans have 23 pairs of chromosomes, 46 in total, in the nucleus of most cells (NIH NHGRI). Genotype is the genetic makeup; phenotype is the observable trait. A Punnett square predicts the probabilities of offspring traits. |
|
Cell division |
Mitosis makes two identical body cells (growth and repair). Meiosis makes sex cells (gametes) that carry one copy of each chromosome, half the usual number (NIH NHGRI). |
|
Classification |
From broadest to narrowest: domain, kingdom, phylum, class, order, family, genus, species. |
|
Human body systems |
Circulatory (heart, blood vessels, blood), respiratory (lungs, gas exchange), digestive (the small intestine absorbs most nutrients), nervous (brain, spinal cord, nerves), excretory (kidneys filter blood), endocrine (hormones), immune (defends against disease). Red blood cells carry oxygen, white blood cells fight infection, and platelets help blood clot. |
|
Ecology |
Producers make food from sunlight; consumers eat other organisms; decomposers break down dead matter. Energy in a food chain starts with the Sun and is passed on through producers. Symbiosis types: mutualism (both benefit), parasitism (one benefits, one is harmed), commensalism (one benefits, the other is unaffected). |
|
Evolution |
Organisms with traits that help them survive and reproduce pass those traits on more often. This is natural selection. |
Earth and space science
|
Topic |
Know this |
|
Earth’s layers |
Crust, mantle, outer core (liquid), inner core (solid). (USGS) |
|
Plate tectonics |
Earth’s crust is broken into moving tectonic plates. Most earthquakes occur along plate boundaries. Many volcanoes form there too. (USGS) |
|
Rocks |
Igneous rock forms from cooled magma or lava, sedimentary rock from compacted and cemented sediment, and metamorphic rock from existing rock changed by heat and pressure. (USGS) |
|
Weathering and erosion |
Weathering breaks rock down, erosion moves the pieces, and deposition drops them in a new place. (National Park Service) |
|
Atmosphere |
About 78% nitrogen and 21% oxygen by volume in dry air (NOAA). Five layers from the ground up: troposphere (where weather happens), stratosphere (ozone layer), mesosphere, thermosphere, exosphere (NASA). |
|
Weather and water |
Weather is short-term conditions; climate is the long-term pattern. Water cycle: evaporation, condensation, precipitation, collection. |
|
Earth and Sun |
Rotation (once a day) causes day and night. Revolution (once a year) is Earth’s orbit around the Sun. Earth’s tilt, not its distance from the Sun, causes the seasons. (NOAA, NASA) |
|
Moon |
Phases come from the changing view of the Moon’s sunlit half. The Moon’s gravity is the main cause of tides; the Sun’s tide-generating force is about half the Moon’s. (NOAA) |
|
Solar system |
Eight planets, in order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Pluto was reclassified as a dwarf planet in 2006. (NASA) The Sun is a star. A light-year is a unit of distance, not time. |
Physical science
|
Topic |
Know this |
|
States of matter |
Solid, liquid, gas. State changes: melting, freezing, evaporation, condensation, sublimation (solid to gas). |
|
Density |
Density = mass ÷ volume. An object floats in a fluid if it is less dense than the fluid. |
|
Atoms |
Protons (positive) and neutrons (no charge) are in the nucleus; electrons (negative) are outside it. Atomic number = number of protons. |
|
Periodic table |
Elements are arranged by atomic number. Elements in the same column have similar properties. Noble gases are mostly unreactive. Metals conduct heat and electricity well. |
|
Compounds and mixtures |
A compound has elements chemically bonded (water, H₂O). A mixture is physically combined, and each part keeps its properties. A solution is a mixture. |
|
Physical vs. chemical change |
Physical change alters form or state (melting ice). Chemical change makes a new substance (rusting, burning). |
|
Acids and bases |
The pH scale runs from 0 to 14. Below 7 is acidic, 7 is neutral, above 7 is basic. (USGS) |
|
Motion |
Speed = distance ÷ time. Velocity is speed with direction. Acceleration is a change in velocity. |
|
Newton’s laws |
1st: an object stays at rest or in uniform motion unless an outside force acts on it. 2nd: force = mass × acceleration. 3rd: every action has an equal and opposite reaction, and the two forces act on different objects. (NASA Glenn) |
|
Mass and weight |
Mass is the amount of matter and does not change with location. Weight is the pull of gravity on that mass. |
|
Energy |
Kinetic energy is energy of motion; potential energy is stored energy. Energy changes form but is not created or destroyed. Solar and wind are renewable; coal and oil are not. |
|
Heat |
Heat flows from hotter to colder objects. Transfer by conduction (contact), convection (moving fluid), and radiation (waves) (NOAA). Water freezes at 0°C (32°F) and boils at 100°C (212°F) at sea level. °F = (°C × 9/5) + 32. |
|
Waves, light, sound |
Sound needs a medium and cannot travel through a vacuum; light can. Light travels much faster than sound, which is why you see lightning before you hear thunder. Frequency sets pitch; amplitude sets loudness. |
|
Electricity and magnetism |
Current flows only in a complete circuit. Metals are conductors; rubber and plastic are insulators. In a parallel circuit, the other branches keep working if one fails. Like magnetic poles repel; opposite poles attract. |
Look-Alike Terms That Cause Mistakes
Many missed GS questions come from two terms that sound similar. Know the difference cold.
|
Pair |
The difference |
|
Mass / weight |
Mass is the amount of matter; weight is the gravitational pull on it. |
|
Speed / velocity |
Velocity includes direction. |
|
Heat / temperature |
Temperature is the average motion of particles; heat is energy transferred. |
|
Weather / climate |
Weather is short-term; climate is long-term. |
|
Weathering / erosion |
Weathering breaks rock down; erosion carries it away. |
|
Rotation / revolution |
Rotation is spinning on an axis; revolution is orbiting another body. |
|
Mitosis / meiosis |
Mitosis makes identical body cells; meiosis makes sex cells with half the chromosomes. |
|
Genotype / phenotype |
Genotype is the genes; phenotype is the visible trait. |
|
Element / compound |
An element is one type of atom; a compound is chemically bonded elements. |
|
Physical / chemical change |
Only a chemical change produces a new substance. |
|
Conduction / convection / radiation |
Contact, moving fluid, and waves. |
|
Renewable / nonrenewable |
Renewable resources replenish on a human timescale. |
How to Answer GS Questions
The official test-taking advice for every version is to read carefully, watch the time, and rule out wrong choices before guessing. Here is how that applies to a recall test. These steps are our recommendations, not official rules.
- Answer what you know first, fast. With about 48 seconds per question on the CAT and about 26 on paper, a question you know should take seconds.
- Read the stem for the question type. “Because” and “why” questions want the reason or mechanism, not just another true fact.
- Eliminate for a reason. Cross out choices that are false, that are true but do not answer this question, or that describe a different concept than the one asked (a look-alike term).
- Sanity-check units and scales. Celsius versus Fahrenheit, mass versus weight, and small versus large quantities cause avoidable misses.
- Do not sink time into a blank. More time will not help you remember a fact you never learned. Eliminate what you can and choose the best remaining answer. On paper, mark it and return if time allows.
- Commit on the CAT. You cannot go back once you submit. If time is short at the end, answer legitimately rather than clicking at random.
How GS Affects Your Score
GS does not count toward your AFQT. The official ASVAB program says the AFQT is calculated from four subtests only: Arithmetic Reasoning, Mathematics Knowledge, Paragraph Comprehension, and Word Knowledge (Understanding ASVAB Scores). The AFQT decides enlistment eligibility, so a low GS score by itself does not keep you from enlisting.
GS can still matter for your job. After you qualify to enlist, each service combines subtest scores into its own composite scores, often called line scores, to decide which jobs you qualify for. GS is used in some of them. For example, published guides list GS in the Army’s Skilled Technical composite and in the Air Force’s Electronics composite (Military.com). Other guides also list GS in the Army’s Electronics and General Maintenance composites. Formulas, cutoffs, and job requirements differ by branch and change over time, and I could not verify the current formulas on an official ASVAB page. Confirm the composites and minimum scores for your target job with a recruiter or the branch’s official site before you set a GS goal. [INTERNAL LINK: ASVAB line scores guide]
How scores are reported. Subtest scores are standard scores with a mean of 50 and a standard deviation of 10, so a 50 is average for the reference group and not a count of correct answers (Understanding ASVAB Scores). The official pages do not publish a separate passing score for GS.
Retesting. After your first ASVAB you must wait one calendar month to retest, another calendar month for a second retest, and six calendar months after that. Scores can be used for enlistment for up to two years (FAQs).
Study Plan
The official program does not endorse a specific prep method. What follows is our own routine, a structure and not a promise of any score.
A four-week routine
|
Week |
Focus |
|
1 |
Take this test cold. Log every miss by area and by reason (template below). |
|
2 |
Rebuild your weakest area using the core-facts table for it. Write out each row from memory. |
|
3 |
Drill the look-alike terms, then practice at the pace of your version (48 seconds per question for the CAT, about 26 for paper). Try the official samples. |
|
4 |
Retake this test and compare which areas you miss, not just the percentage. Then work on your other subtests. [INTERNAL LINK: ASVAB practice tests hub] |
Error log template
|
Question |
Area |
What I chose |
Correct answer |
Why I missed it (didn’t know / look-alike / rushed) |
Flashcards work best for GS
Because GS rewards recognizing many small facts, make one card per fact instead of one card per topic, and review them in short, frequent sessions. [INTERNAL LINK: ASVAB flashcards]
GS and your other subtests
GS is one of the science and technical subtests. If your target job uses composites that include Electronics Information or Mechanical Comprehension, study those alongside GS. [INTERNAL LINK: Electronics Information practice test] [INTERNAL LINK: Mechanical Comprehension practice test]
FAQs
How many questions are on the ASVAB General Science section?
On the proctored CAT-ASVAB, GS has 15 scored questions, and up to 15 unscored tryout questions may also be included. The paper-and-pencil ASVAB has 25 GS questions.
How much time do you get for General Science?
On the proctored CAT-ASVAB the limit is 12 minutes with no tryout questions and 25 minutes when tryout questions are included. The paper version allows 11 minutes. The PiCAT has no time limit on individual subtests.
Does General Science count toward the AFQT?
No. The AFQT uses Arithmetic Reasoning, Mathematics Knowledge, Paragraph Comprehension, and Word Knowledge only.
Does my GS score matter for military jobs?
It can. The services build their own composite scores from subtests, and GS appears in some of them. Requirements vary by branch and job and can change, so check with a recruiter.
What is a good General Science score?
There is no separate official passing score for GS. Subtest scores are standard scores with an average of 50. What counts is whether your GS score helps you meet the composite minimum for the job you want.