Science Trivia for Kids
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95 free Science Trivia for Kids trivia questions with answers — science & nature quiz, new questions added Sep 2026.
59 free Science Trivia for Kids questions with answers. This science quiz is written for kids aged roughly 8 to 12, which lines up with 3rd, 4th and 5th grade science. It covers the topics those years actually teach: the three rock types and the rock cycle, the water cycle, weather and the atmosphere, the planets and the Moon, magnets and simple machines, states of matter, food chains, animal groups and life cycles, and the human body. Roughly a third of the questions are easy enough for a curious 8-year-old, and the rest climb gently to the sort of thing a sharp 5th grader is proud to know. It works for a classroom warm-up, a family quiz night, or a rainy afternoon. Every answer has been checked against a reference source, and each question shows where it came from, so parents and teachers can trust what it teaches.
30 of 95 questions with answers and explanations. Play the quiz
Q 01Which planet is known as the Red Planet?
Mars
Mars looks orange-red because minerals in its dusty soil have rusted, just like an old nail left out in the rain.
Q 02Which is the largest planet in our Solar System?
Jupiter
Jupiter's powerful magnetic field traps charged particles in belts of radiation so intense that it can damage the spacecraft sent to explore it.
Q 03Which planet orbits closest to the Sun?
Mercury
Mercury is closest to the Sun and circles it in just 88 Earth days, yet one sunrise to the next there takes 176 Earth days.
Q 04What kind of object is the Sun?
A star
The Sun is an ordinary star that happens to sit right at the centre of our Solar System. It only looks so big and bright because it is far closer to us than any other star.
Q 05Which gas do plants take in from the air to make their food?
Carbon dioxide
Carbon dioxide and water, with sunlight, become sugar in photosynthesis, and the plant gives off oxygen as a leftover.
Q 06At what temperature does water freeze?
0 °C
0 °C is where water turns to ice at one atmosphere, which is 32 degrees Fahrenheit; it boils at 100 °C.
Q 07What is the chemical formula for water?
H2O
H2O means two hydrogen atoms joined to one oxygen atom, and although hydrogen and oxygen are both gases, together they make liquid water.
Q 08What do some of a baby's bones do as it grows?
Fuse
They fuse together as a child grows, and the gaps between a newborn's skull plates let the head squeeze through at birth.
Q 09Who was the first person to walk on the Moon?
Neil Armstrong
Neil Armstrong took over steering the lunar lander to avoid a rocky crater, then became the first person to step onto the Moon.
Q 10Which is the largest organ in the human body?
Skin
Skin is your largest organ, and its outer layer keeps renewing itself, making new cells to replace the old ones that flake off.
Q 11Which force pulls a dropped ball down toward the ground?
Gravity
Gravity makes a hammer and a feather fall at the same rate when no air slows them, as an Apollo 15 astronaut showed on the Moon.
Q 12Which part of a plant takes in water from the soil?
The roots
The roots soak up water through tiny root hairs, which give them a much larger surface area so they can take in far more.
Q 13What do we call an animal that eats mainly plants?
A herbivore
A herbivore often has wide, flat back teeth for grinding tough leaves and grass, while a carnivore has sharp teeth for tearing meat.
Q 21Which instrument records the waves an earthquake sends through the ground?
A seismograph
A seismograph records the ground's shaking, and scientists use those records to work out where an earthquake struck and how strong it was.
Q 22Which of these metals is a magnet able to pull on?
Iron
Iron, nickel and cobalt are the classic magnetic metals, which is why a magnet sticks to most steel, an alloy of iron, but not to an aluminium can.
Q 23Which four states of matter can you see in everyday life?
Solid, liquid, gas and plasma
Solid, liquid, gas and plasma are the four states seen in everyday life, and plasma is gas so energized that electrons break free of its atoms, which is how a neon sign glows.
Q 14Which natural material is the hardest of all?
Diamond
Diamond sits at the very top of the Mohs hardness scale, so it can scratch every other natural material but almost nothing can scratch it.
Q 15Which rock is so full of tiny gas bubbles that it can float on water?
Pumice
Pumice is packed with gas bubbles trapped as it erupted from a volcano, so rafts of it can float on the ocean for years before sinking.
Q 16Which type of rock forms when hot melted rock cools down and hardens?
Igneous
Igneous rock that cools slowly underground grows big crystals, like granite, while lava that cools fast at the surface makes fine-grained basalt.
Q 17What are the flat layers that sedimentary rocks build up in called?
Strata
Strata pile up one on top of another over time, so the deeper a layer lies, the older it usually is.
Q 18Heat and pressure deep underground can change limestone into which rock?
Marble
Marble is limestone whose crystals regrew under heat and pressure, and Michelangelo carved his statue of David from a block of it.
Q 19Which ancient remains get their name from a Latin word meaning 'dug up'?
Fossils
Fossils take their name from Latin fossilis, 'dug up', and the English word once meant any rock or mineral dug out of the earth, not just ancient remains.
Q 20Before a volcano erupts, melted rock collects deep underground in what?
A magma chamber
A magma chamber can empty so fast in a huge eruption that the ground above caves in, leaving a giant bowl-shaped hollow called a caldera.
Q 24When water on the surface of a puddle turns into a gas and disappears into the air, what is that called?
Evaporation
Only the fastest-moving molecules escape, so evaporation cools whatever is left behind, which is why sweat cools you down.
Q 25Water vapor turning back into liquid drops on the outside of a cold glass is an example of what?
Condensation
Condensation is also why glasses fog up when someone steps from a cold, air-conditioned room out into warm, humid air.
Q 26Clouds are made mostly of what?
Tiny water droplets and ice crystals
Tiny water droplets and ice crystals make up clouds, and the droplets are so small and light that they stay floating in the air instead of falling.
Q 27What is the lowest layer of Earth's atmosphere, where most weather happens, called?
The troposphere
The troposphere holds nearly all of the air's water vapour, which is why almost all clouds, rain and storms happen inside it.
Q 28Which part of the upper atmosphere soaks up most of the Sun's harmful ultraviolet light?
The ozone layer
The ozone layer was thinned by CFC chemicals from sprays and fridges, but after the Montreal Protocol phased them out, it is expected to recover within decades.
Q 29Which gas, lighter than air and unable to burn, is used to fill party balloons?
Helium
Helium is the second-lightest element and cannot burn, which is why it replaced explosive hydrogen in balloons and airships; the Sun makes helium by fusing hydrogen.
Q 30Which instrument measures how hot or cold something is?
A thermometer
A classic glass thermometer works because the liquid inside expands as it warms, so a thin line of it rises up the narrow tube.