A leaf is 3.5 centimeters long. What is its length in millimeters?NIST, Metric (SI) Prefixes. Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), A. Nature of Science and Engineering: standard equipment in the laboratory and field.
A student says, "Evolution is only a theory, so it is just a guess." Which reply uses the word theory as scientists do?UC Museum of Paleontology, Understanding Science 101, "Science at multiple levels". Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), A. Nature of Science and Engineering: nature of scientific knowledge.
A teacher is diluting concentrated acid before a lab. Which way of mixing does the school laboratory safety guide call for?NIOSH and CPSC, School Chemistry Laboratory Safety Guide, "Safety Do's and Don'ts for Students": chemical handling. Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), A. Nature of Science and Engineering: safety, materials and standard equipment.
Show all 50 questions (47 more)
Nature and impact of science, continued
In which layer of the atmosphere does the ozone layer lie, and what does it absorb?US EPA, Basic Ozone Layer Science. Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), B. Science, Technology, Society, and the Environment: impact on the environment and society.
Students must design a water filter using only the materials in one kit. In engineering design, what is a limit such as the available materials called?Next Generation Science Standards, DCI Arrangements, ETS1.A: Defining Engineering Problems (grades 3-5). Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), A. Nature of Science and Engineering: engineering design.
Which of these energy sources is classed as nonrenewable?US Energy Information Administration, Energy Explained: Sources of energy. Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), B. Science, Technology, Society, and the Environment: energy production and natural resources.
Which pair of pollutants produces acid rain after it is released into the air?US EPA, What is Acid Rain? Outline: ETS Study Companion for Praxis 5442, I. Nature and Impact of Science and Engineering (14%), B. Science, Technology, Society, and the Environment: impact on the environment and society.
Physical science 15
A car with a mass of 1,200 kilograms speeds up at 2 meters per second squared. What net force acts on it?NASA Glenn Research Center, Beginner's Guide to Aeronautics: Newton's Laws of Motion, second law. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), B. Motion and Stability: Forces and Interactions: forces and motion.
A class burns a candle and feels the heat. Which description fits combustion?NASA Glenn Research Center, Beginner's Guide to Aeronautics: Combustion. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), A. Matter and Its Interactions: chemical reactions.
A cyclist coasts down a steep hill and picks up speed. Which energy change is taking place?US Energy Information Administration, Energy Explained: Forms of energy. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), C. Energy and Waves: energy.
A motor takes in 100 joules of electrical energy and does 80 joules of useful work. What became of the other 20 joules?US Energy Information Administration, Energy Explained: Laws of energy. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), C. Energy and Waves: energy.
A puck glides across smooth ice in a straight line at steady speed after the stick has left it. Which law accounts for this?NASA Glenn Research Center, Beginner's Guide to Aeronautics: Newton's Laws of Motion. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), B. Motion and Stability: Forces and Interactions: forces and motion.
A straw standing in a glass of water looks bent where it meets the surface. Which wave behavior causes this?NASA Science, Tour of the Electromagnetic Spectrum: Wave Behaviors, refraction. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), C. Energy and Waves: waves and their applications.
A swimmer pushes back against the pool wall and shoots forward. What supplies the forward force on the swimmer?NASA Glenn Research Center, Beginner's Guide to Aeronautics: Newton's Laws of Motion, third law. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), B. Motion and Stability: Forces and Interactions: forces and motion.
Deuterium and ordinary hydrogen are isotopes of one element. In what do their atoms differ?US Department of Energy, DOE Explains...Isotopes. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), A. Matter and Its Interactions: structure and properties of matter.
Dry ice goes straight from a solid to a gas with no liquid in between. What is this phase change called?USGS Water Science School, Sublimation and the Water Cycle. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), A. Matter and Its Interactions: structure and properties of matter.
How many molecules of oxygen balance this equation? CH4 + __ O2 → CO2 + 2 H2OPurdue University, General Chemistry Topic Review: Chemical Equations. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), A. Matter and Its Interactions: chemical reactions.
Moving left to right across one period of the periodic table, what rises from each element to the next?Los Alamos National Laboratory, Understanding the Periodic Table. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), A. Matter and Its Interactions: structure and properties of matter.
On a sunny day a black road feels hotter than a pale concrete sidewalk beside it. Which wave behavior explains the difference?NASA Science, Tour of the Electromagnetic Spectrum: Wave Behaviors, absorption. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), C. Energy and Waves: waves and their applications.
Stream A has a pH of 5 and stream B has a pH of 7. How does A compare with B?USGS Water Science School, pH and Water. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), A. Matter and Its Interactions: structure and properties of matter.
Twelve wave crests pass a dock post in 4 seconds. What is the frequency of the waves?NASA Science, Tour of the Electromagnetic Spectrum: Anatomy of an Electromagnetic Wave. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), C. Energy and Waves: waves and their applications.
Which action makes an electric current flow in a coil of wire?US Energy Information Administration, Energy Explained: Magnets and electricity. Outline: ETS Study Companion for Praxis 5442, II. Physical Science (30%), B. Motion and Stability: Forces and Interactions: electricity and magnetism.
Life science 15
A plant cell and an animal cell both have a cell membrane. What is the membrane's job?National Human Genome Research Institute (NIH), Talking Glossary: Cell Membrane (Plasma Membrane). Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), A. From Molecules to Organisms: Structures and Processes: structure and function, cells.
Allele T is dominant and allele t is recessive. A Tt plant is crossed with a tt plant. What share of the offspring is expected to show the recessive trait?National Human Genome Research Institute (NIH), Talking Glossary: Recessive Traits and Alleles. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), C. Heredity and Biological Evolution: variation of traits.
Drainage from fertilized fields carries excess nitrogen down rivers to the sea. Which condition can the excess nitrogen lead to there?USGS Water Science School, Nitrogen and Water. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), B. Ecosystems: Interactions, Energy, and Dynamics: ecosystem dynamics, functioning and resilience.
During photosynthesis a plant absorbs carbon dioxide and sunlight. What fuel does it make?NASA Earth Observatory, The Carbon Cycle. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), A. From Molecules to Organisms: Structures and Processes: matter and energy flow in organisms.
In fall and winter, as plants die back, which processes return carbon dioxide to the atmosphere?NASA Earth Observatory, The Carbon Cycle. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), B. Ecosystems: Interactions, Energy, and Dynamics: cycling of matter and energy transfer.
In which molecule is the chemical energy produced by mitochondria stored?National Human Genome Research Institute (NIH), Talking Glossary: Mitochondria. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), A. From Molecules to Organisms: Structures and Processes: matter and energy flow in organisms.
On dark lava rock, hawks catch pale lizards more often than dark ones. Color is inherited, and after many generations most lizards there are dark. What does this show?UC Museum of Paleontology, Understanding Evolution, Evolution 101: Natural selection. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), C. Heredity and Biological Evolution: natural selection and adaptation.
On which cell structure is messenger RNA read and turned into a chain of amino acids?National Human Genome Research Institute (NIH), Talking Glossary: Translation. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), C. Heredity and Biological Evolution: inheritance of traits.
One strand of a DNA molecule reads A-T-G-C. What does the matching strand read?National Human Genome Research Institute (NIH), Talking Glossary: Deoxyribonucleic Acid (DNA). Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), C. Heredity and Biological Evolution: inheritance of traits.
Reef-building corals house algae called zooxanthellae. The algae get shelter and the coral gets food made by photosynthesis. What is this relationship?NOAA National Ocean Service, Corals Tutorial: What is Zooxanthellae? Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), B. Ecosystems: Interactions, Energy, and Dynamics: interdependent relationships in ecosystems.
What must a virus do to make copies of itself?National Human Genome Research Institute (NIH), Talking Glossary: Virus. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), A. From Molecules to Organisms: Structures and Processes: structure and function, cell types.
Which biome is the coldest and gets so little precipitation that it resembles a desert?NASA Earth Observatory, Mission: Biomes, Tundra. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), B. Ecosystems: Interactions, Energy, and Dynamics: ecosystem dynamics, functioning and resilience.
Which mutation can be passed on to an organism's offspring?National Human Genome Research Institute (NIH), Talking Glossary: Mutation. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), C. Heredity and Biological Evolution: variation of traits.
Which organisms form the base of several aquatic food webs?NOAA National Ocean Service, What are phytoplankton? Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), B. Ecosystems: Interactions, Energy, and Dynamics: cycling of matter and energy transfer.
Which process makes egg and sperm cells that carry half the usual number of chromosomes?National Human Genome Research Institute (NIH), Talking Glossary: Meiosis. Outline: ETS Study Companion for Praxis 5442, III. Life Science (30%), A. From Molecules to Organisms: Structures and Processes: growth and development, cell reproduction.
Earth and space science 13
A cliff shows flat sedimentary layers that have never been disturbed. Where is the oldest layer?USGS, Geologic Time: Relative Time Scale. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: the history of planet Earth.
A student says metamorphic rock forms when rock melts and hardens again. What is wrong with that?USGS, What are metamorphic rocks? Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), B. Earth's Systems: Earth materials and systems.
A student writes that summer comes when Earth is nearest the Sun. Which fact corrects this?NASA Space Place, What Causes the Seasons? Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: Earth and the solar system.
About how much of all the water on Earth is held in the oceans?USGS Water Science School, How Much Water is There on Earth? Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), B. Earth's Systems: roles of water in Earth's surface processes.
Along the Mid-Atlantic Ridge, plates move apart and magma builds new crust. Which kind of plate boundary is it?USGS, This Dynamic Earth: Understanding plate motions. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), B. Earth's Systems: plate tectonics.
At which phases of the Moon do spring tides occur?NOAA National Ocean Service, What are spring and neap tides? Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), B. Earth's Systems: roles of water in Earth's surface processes.
Carbon-14 has a half-life of 5,730 years. A piece of wood holds one quarter of the carbon-14 it had when the tree died. About how old is it?USGS, Geologic Time: Radiometric Time Scale. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: the history of planet Earth.
Granite forms when magma is trapped below the surface and cools very slowly. What kind of rock is granite?USGS, What are igneous rocks? Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), B. Earth's Systems: Earth materials and systems.
How are the Sun, the Moon and Earth lined up during a solar eclipse?NASA Science, Types of Solar Eclipses. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: Earth and the solar system.
To which class of galaxies does the Milky Way belong?NASA Science, Galaxy Types. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: the universe and its stars.
What drives the deep-ocean currents of the thermohaline circulation?NOAA National Ocean Service, Currents Tutorial: Thermohaline Circulation. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), B. Earth's Systems: roles of water in Earth's surface processes.
Which observation is the oldest light that can be seen in the universe?NASA Science, The Big Bang. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: the universe and its stars.
Which phase of the Moon comes directly after first quarter?NASA Science, Moon Phases. Outline: ETS Study Companion for Praxis 5442, IV. Earth and Space Science (26%), A. Earth's Place in the Universe: Earth and the solar system.
How this list was compiled: Our own questions, written to the content topics of the ETS Study Companion for Praxis Middle School Science (5442) (https://www.ets.org/pdfs/praxis/5442.pdf, read 2026-10-09; test page https://praxis.ets.org/test/5442.html): Nature and Impact of Science and Engineering 14%, Physical Science 30%, Life Science 30%, Earth and Space Science 26%. The bank holds 7, 15, 15 and 13 questions. Every fact was read on 2026-10-09 on the public page the question names: NASA (science.nasa.gov, Glenn Research Center, Space Place, Earth Observatory), NOAA National Ocean Service, USGS (This Dynamic Earth, Geologic Time, Water Science School), the National Human Genome Research Institute of NIH (genome.gov), the Energy Information Administration, the Department of Energy, EPA, NIST, Los Alamos National Laboratory, the NIOSH School Chemistry Laboratory Safety Guide, the Next Generation Science Standards, Purdue University and the UC Museum of Paleontology. Arithmetic answers are worked out again from the numbers in the question. Licence: Questions, choices and explanations are original work of this site.
How it works
This free Praxis 5440 practice test follows the outline of Praxis Middle School Science (5442), the code ETS lists today: 50 questions of our own, each with its source. It is unofficial and not affiliated with or endorsed by ETS.
Read the full guide
What the test covers
ETS lists nature and impact of science and engineering (14%), physical science (30%), life science (30%) and earth and space science (26%), by the Study Companion read October 9, 2026. This bank holds 7, 15, 15 and 13 questions. About 30 percent of the real questions sit inside a teaching task, and some here do too.
Timing
Exam mode asks the 50 questions here in 60 minutes, the pace of the real test.
Where the answers come from
Each explanation names the public page its fact was read on: NASA, NOAA, USGS, the National Institutes of Health, other agencies and two universities.
ETS says no calculator is needed, and a periodic table sits on the Help screen of the real test.
More than 40 percent of the real questions use a science and engineering practice, such as reading data or judging a model.
Questions and answers
Is Praxis 5440 the same test as 5442?
Middle School Science once carried the code 5440. On October 9, 2026 the ETS site had no page for 5440; the Middle School Science test it lists is 5442, and these questions follow that outline. Ask your state agency which code it accepts.
Is this Praxis 5440 online practice test the real exam?
No. All 50 questions were written for this site from the content topics ETS publishes for Middle School Science (5442). None repeats or rewords a real test question or an ETS sample question, and a result here is not a forecast of your score.
What does this 5440 Praxis practice test cover?
Matter, forces, energy and waves; cells, ecosystems, heredity and evolution; Earth and space; and how science and engineering work and affect society. The organ systems that the ETS outline also lists are not in this bank.
How many questions are on the Praxis Middle School Science test?
125 selected-response questions in 150 minutes, delivered on a computer. ETS says the test may include questions that are not scored.
What is a passing score on Praxis 5442?
There is no single one. ETS says ETS sets no passing scores; they vary by state, so check the requirement where you will be licensed. This page reports the number right only.