Scientific Knowledge — Apply physical and biological science concepts. - Armed Services Vocational Aptitude Battery ASVAB

SECTION 1

Historical Context & Motivation

Understanding the physical and biological world has always been central to human progress, and it is equally critical to military readiness. The ASVAB General Science subtest measures your ability to recall and apply concepts from physics, chemistry, biology, and earth science — the same knowledge that helps service members understand ballistics, field medicine, weather patterns, and equipment maintenance. The history of science is a story of people asking clear questions about nature and testing answers through observation and experiment.

1687 • Newton's Principia Published

Isaac Newton formalized the three laws of motion and the law of universal gravitation, laying the foundation for classical physics that still describes how vehicles, projectiles, and aircraft move.

1859 • Darwin's Origin of Species

Charles Darwin proposed natural selection as the mechanism driving evolution, unifying biology under one explanatory framework for the diversity of life on Earth.

1869 • Mendeleev's Periodic Table

Dmitri Mendeleev organized the chemical elements by atomic mass and properties, creating the periodic table — the map of all matter used in chemistry today.

1953 • Structure of DNA Discovered

Watson and Crick described the double-helix structure of DNA, revealing how genetic information is stored, copied, and passed from one generation to the next.

1968 • ASVAB First Administered

The U.S. Department of Defense introduced the Armed Services Vocational Aptitude Battery to assess recruits' science, math, and technical knowledge for military occupational specialty placement.

The General Science subtest does not ask you to memorize obscure facts. Instead, it tests whether you can apply fundamental science principles — the kind that explain why a parachute slows your fall, why infections spread, or why metals expand when heated. This lesson covers the most important physical and biological concepts you will encounter on test day.

SECTION 2

Core Principles & Definitions

The ASVAB General Science section spans two broad domains: physical science (physics and chemistry) and biological science (life science, ecology, and human anatomy). Across both domains, five foundational ideas appear repeatedly. Master these and you will be equipped to handle most General Science questions.

Energy & Its Transformations

Energy cannot be created or destroyed, only converted from one form to another. Kinetic energy is the energy of motion; potential energy is stored energy due to position or chemical bonds.

Forces & Motion

Newton's three laws describe how force affects the motion of objects. Unbalanced forces cause acceleration; balanced forces result in constant velocity or rest.

Cell Theory & Life Processes

All living organisms are made of cells, the basic unit of life. Cells carry out metabolism, reproduce, respond to stimuli, and maintain homeostasis.

Matter & Chemical Reactions

All matter is composed of atoms. In chemical reactions, atoms rearrange into new combinations. The total mass of reactants equals the total mass of products (conservation of mass).

Heredity & Evolution

Traits are passed from parents to offspring through DNA. Over generations, populations change through natural selection, where organisms better adapted to their environment are more likely to survive and reproduce.

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KEY TAKEAWAY

Think of these five principles like the basic equipment every soldier carries. Just as you build mission-specific loadouts from standard-issue gear, every ASVAB science question is built from combinations of these core ideas. If you understand energy, forces, cells, matter, and heredity, you can reason through even an unfamiliar question.

SECTION 3

Visual Explanation — Forces & Energy

The diagram below illustrates how potential energy converts into kinetic energy as an object moves down a ramp. At the top, the object has maximum gravitational potential energy and zero kinetic energy. At the bottom, the relationship reverses. The total mechanical energy remains constant (ignoring friction), which is the law of conservation of energy in action.

Point A (violet) has maximum gravitational potential energy. Point B (amber) shows the halfway conversion. Point C (cyan) has maximum kinetic energy. The small bar charts on the left side of each position show the PE-to-KE ratio.

This concept comes up on the ASVAB in questions like: 'A rock is dropped from a cliff. At what point does it have the most kinetic energy?' The answer is always at the lowest point, just before impact, because all the stored potential energy has been converted into the energy of motion.

SECTION 4

Key Equations in Physical Science

The ASVAB General Science subtest rarely requires heavy calculation, but knowing key formulas helps you reason through multiple-choice answers. Below are the most commonly referenced physical science equations.

NEWTON'S SECOND LAW

F = m × a

F = net force (Newtons, N), m = mass (kilograms, kg), a = acceleration (m/s²). More force on the same mass means more acceleration.

KINETIC ENERGY

KE = ½ × m × v²

KE = kinetic energy (Joules, J), m = mass (kg), v = velocity (m/s). Doubling speed quadruples kinetic energy.

GRAVITATIONAL POTENTIAL ENERGY

PE = m × g × h

PE = potential energy (J), g = acceleration due to gravity (9.8 m/s²), h = height above a reference point (m).

SPEED / VELOCITY

v = d / t

v = speed or velocity (m/s), d = distance (m), t = time (s). This is the most basic relationship in kinematics.

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ASVAB TIP

You will not have a calculator on the ASVAB. Focus on understanding what happens when a variable increases or decreases. For example, if mass doubles in F = m × a and force stays the same, acceleration is cut in half.

SECTION 5

Biological Science — Cells, Systems, & Ecology

Roughly half of the General Science questions deal with life science. The ASVAB expects you to understand cell structure, human body systems, genetics, and ecology. The diagram below shows a typical animal cell with its key organelles labeled.

The nucleus (violet) houses DNA. Mitochondria (cyan) produce energy via cellular respiration. The cell membrane (green) controls what enters and exits the cell. Ribosomes (red) build proteins.

Body System	Key Organs	Primary Function
Circulatory	Heart, blood vessels, blood	Transports oxygen, nutrients, and waste products throughout the body
Respiratory	Lungs, trachea, diaphragm	Exchanges oxygen and carbon dioxide between the body and the environment
Nervous	Brain, spinal cord, nerves	Receives stimuli and coordinates responses; controls voluntary and involuntary actions
Digestive	Stomach, intestines, liver	Breaks down food into nutrients the body can absorb and use for energy
Musculoskeletal	Bones, muscles, joints	Provides structure, supports movement, and protects internal organs

Major Human Body Systems Tested on the ASVAB

In ecology, remember the hierarchy: organism → population → community → ecosystem → biome → biosphere. Producers (plants) convert sunlight into chemical energy via photosynthesis. Consumers (animals) eat producers or other consumers to obtain energy. Decomposers (bacteria, fungi) break down dead matter and recycle nutrients back into the soil. Energy flows in one direction through a food chain, but nutrients cycle repeatedly.

SECTION 6

Worked Example — Applying Science Concepts

Let's walk through a problem that combines physical science reasoning — the kind you'll see on the ASVAB.

How much kinetic energy does a 2 kg object have when moving at 6 m/s?

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Step 1 — Identify the equation

We need the kinetic energy formula: KE = ½ × m × v².
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Step 2 — Plug in known values

Mass (m) = 2 kg, velocity (v) = 6 m/s. Substituting: KE = ½ × 2 × 6².
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Step 3 — Square the velocity

6² = 36. So KE = ½ × 2 × 36.

v² = 36
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Step 4 — Multiply

½ × 2 = 1. Then 1 × 36 = 36.

KE = 36 Joules
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Step 5 — Interpret the result

The 2 kg object moving at 6 m/s has 36 Joules of kinetic energy. Notice that if the speed doubled to 12 m/s, the KE would be ½ × 2 × 144 = 144 J — four times as much. Speed has a much bigger effect on kinetic energy than mass does because velocity is squared.

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BIOLOGY REASONING EXAMPLE

Question: 'Which organelle is called the powerhouse of the cell?' Answer: The mitochondrion. It performs cellular respiration, converting glucose and oxygen into ATP (adenosine triphosphate), the molecule cells use as their primary energy currency. Think of mitochondria as tiny generators inside each cell — without them, the cell has no power.

SECTION 7

Physical vs. Biological Science — Key Comparisons

The ASVAB tests both physical and biological science, so understanding their similarities and differences helps you quickly identify which domain a question targets. The table below compares the two domains side by side.

Feature	Physical Science	Biological Science
Focus	Non-living matter and energy (forces, waves, chemical reactions)	Living organisms and life processes (cells, genetics, ecology)
Core methods	Controlled experiments, mathematical models, measurements	Observation, classification, field studies, dissection
Key equations	F = ma, KE = ½mv², v = d/t, Ohm's law	Punnett squares, Hardy-Weinberg (less formula-heavy overall)
ASVAB question style	Often asks what happens if a variable changes (cause-effect reasoning)	Often asks for identification or classification of structures and processes
Military relevance	Ballistics, electronics, vehicle mechanics, weather	Field medicine, NBC (nuclear/biological/chemical) defense, nutrition

Comparing Physical and Biological Science on the ASVAB

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KEY TAKEAWAY

Think of physical science questions as asking "What happens when…?" and biological science questions as asking "What is this and what does it do?" In the military, both matter: a combat medic needs to know anatomy (biology) and a mechanic needs to understand heat transfer (physics). Recognizing the question type helps you activate the right mental toolkit.

SECTION 8

Connecting to Advanced Concepts

The ASVAB General Science subtest sticks to foundational concepts, but knowing how those foundations connect to more advanced ideas can give you an edge. It also previews topics you may study in military training or technical schools.

ASVAB-Level Concept	Advanced Extension	Military Application
Newton's Laws of Motion	Projectile motion, orbital mechanics	Ballistics calculations, satellite tracking
Basic electricity (Ohm's Law)	Circuit analysis, electromagnetism	Radio/electronics repair, avionics
Cell structure and function	Immunology, microbiology	Combat medic training, CBRN defense
States of matter	Thermodynamics, phase diagrams	Engine maintenance, fuel systems
Ecology & food chains	Environmental science, toxicology	Environmental compliance, water purification

From ASVAB Foundations to Military Technical Skills

Keep in mind that your General Science score contributes to several ASVAB composite scores that determine which Military Occupational Specialties (MOS) you qualify for. A strong performance here opens doors to technical fields like electronics, medical, and mechanical maintenance roles. Even if a question seems more advanced than what you studied, the underlying principle is almost always one of the five core ideas from Section 2.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

A car is traveling at constant speed on a straight, level road. Are the forces acting on the car balanced or unbalanced? Explain your reasoning.

Show answer

The forces are balanced. According to Newton's First Law, an object moving at constant velocity has zero net force acting on it. The engine's forward force exactly equals air resistance and friction combined. If the forces were unbalanced, the car would accelerate or decelerate, meaning its speed would change.

Question 2: BASIC CALCULATION

A 5 kg box is pushed with a net force of 20 N. What is the acceleration of the box?

Show answer

Using Newton's Second Law, F = m × a, we rearrange to find a = F / m. Substituting: a = 20 N / 5 kg = 4 m/s². This means the box speeds up by 4 meters per second every second. If the force were doubled to 40 N (same mass), the acceleration would also double to 8 m/s².

Question 3: INTERMEDIATE

In a food chain: grass → grasshopper → frog → snake → hawk. If a disease wiped out all the frogs, what would most likely happen to the grasshopper and snake populations in the short term?

Show answer

With frogs removed, grasshoppers lose a major predator, so their population would likely increase in the short term. Meanwhile, snakes lose their primary food source, so their population would likely decrease. This demonstrates how removing one link in a food chain creates ripple effects in both directions. Over time, the increased grasshopper population could also damage the grass supply.

Question 4: APPLIED

A soldier drops a 0.5 kg canteen from a helicopter hovering at 40 meters. Using PE = mgh (g = 10 m/s² for simplicity), how much potential energy does the canteen have before it falls? What form does that energy take just before it hits the ground?

Show answer

PE = m × g × h = 0.5 kg × 10 m/s² × 40 m = 200 Joules. Just before hitting the ground, all of the gravitational potential energy has been converted into kinetic energy (energy of motion), so KE ≈ 200 J (ignoring air resistance). This is the conservation of energy in action: the total energy stays the same, but it transforms from stored (potential) to moving (kinetic).

Question 5: CRITICAL THINKING

Both plant and animal cells have mitochondria, but only plant cells have chloroplasts. Why do plant cells need both organelles? How does the relationship between photosynthesis and cellular respiration demonstrate energy transformation?

Show answer

Chloroplasts capture light energy and convert it into glucose (chemical energy) through photosynthesis. However, glucose is a storage molecule — the cell cannot directly use it to power its activities. Mitochondria then break down that glucose through cellular respiration, producing ATP, which the cell actually uses for energy. This is a two-step energy transformation: light energy → chemical energy (glucose) → usable chemical energy (ATP). Plants need both organelles because making glucose is only half the job; they still need to convert it into a usable form.

SUMMARY

Lesson Summary

Summary

The ASVAB General Science subtest assesses your ability to apply five foundational ideas across physical science and biological science. In physics, remember that F = m × a governs how forces produce motion, KE = ½mv² and PE = mgh describe energy transformations, and the law of conservation of energy guarantees that energy changes form but is never lost.

In biology, every living thing is made of cells with specialized organelles: the nucleus stores DNA, mitochondria generate ATP through cellular respiration, and ribosomes build proteins. Know the major human body systems (circulatory, respiratory, nervous, digestive, musculoskeletal) and how food chains show energy flow through ecosystems. Physical science questions typically ask what happens when a variable changes; biology questions often ask you to identify structures or explain life processes. Mastering both domains strengthens your General Science score and opens pathways to technical military occupational specialties.