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99 free Science Trivia for Kids trivia questions with answers — science & nature quiz, new questions added Aug 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 99 questions with answers and explanations. Play the quiz
Q 01Which planet is known as the Red Planet?
Mars
Mars looks orange-red from Earth because its surface is covered in iron oxide, which is the same rusty stuff you see on an old nail left out in the rain.
Q 02Which is the largest planet in our Solar System?
Jupiter
Jupiter is the fifth planet out from the Sun and bigger than all the other planets put together. Its famous Great Red Spot is a storm wider than Earth.
Q 03Which planet orbits closest to the Sun?
Mercury
Mercury is the first planet out from the Sun and also the smallest planet in the Solar System.
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
Every drop of water is made of tiny molecules with two hydrogen atoms joined to one oxygen atom.
Q 08How many bones are in a grown-up person's body?
206
A baby is born with around 270 bones, and some of them join together as the child grows, leaving about 206 by adulthood.
Q 09Who was the first person to walk on the Moon?
Neil Armstrong
Neil Armstrong stepped onto the Moon on 20 July 1969 as commander of Apollo 11. Buzz Aldrin followed him out minutes later and became the second person to walk there.
Q 10Which is the largest organ in the human body?
Skin
Your skin covers you from head to toe and makes up roughly a sixth of your whole body weight.
Q 11Which force pulls a dropped ball down toward the ground?
Gravity
Gravity draws objects with mass toward each other, and it is what gives everything on Earth its weight.
Q 12Which part of a plant takes in water from the soil?
The roots
Tiny root hairs soak up water and dissolved minerals underground, and tubes inside the plant carry them up to the rest of it.
Q 13Which gas makes up most of the air we breathe?
Nitrogen
Nitrogen is about 78 percent of dry air. Oxygen, the part our bodies actually use, is only about 21 percent.
What do we call an animal that eats only plants?
Q 21A volcano lets lava, ash and gases escape from what underground pocket of melted rock?
A magma chamber
A magma chamber is the underground pocket of molten rock that feeds a volcano; when pressure builds, lava, ash and gas escape through the vent. Most volcanoes on Earth are actually under the ocean.
Q 22What kind of energy waves does an earthquake send rippling through the ground?
Seismic waves
Seismic waves are the vibrations an earthquake sends through the ground, and a seismograph records them; the magnitude 9.5 Chile earthquake of 1960 registered on instruments around the world.
Q 23Which of these metals is a magnet able to pull on?
Iron
A herbivore
A herbivore lives mainly on leaves, fruit and seeds. Cows, rabbits and giraffes are all herbivores.
Q 15Which 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 16What are the three main types of rock?
Igneous, sedimentary and metamorphic
Igneous, sedimentary and metamorphic rocks can each slowly turn into either of the others; geologists call that endless loop the rock cycle.
Q 17Which type of rock forms when hot melted magma or lava cools down and hardens?
Igneous
Igneous rock forms when magma or lava cools and hardens; the name comes from the Latin igneus, meaning fiery. Basalt and granite are two everyday examples.
Q 18What are the flat layers that sedimentary rocks build up in called?
Strata
Strata are the flat layers, or beds, that sedimentary rock settles into over long periods. Fossils are usually found in them because the layers bury and protect whatever falls in.
Q 19Which type of rock is made when heat and pressure change an existing rock without melting it?
Metamorphic
Marble is a metamorphic rock that started out as limestone; slate started out as shale.
Q 20The word 'fossil' comes from a Latin word meaning what?
Obtained by digging
'Fossil' comes from the Latin fossilis, meaning obtained by digging, because early finds were dug out of the ground. Fossils can be bones, shells, footprints or a bug trapped in amber.
Iron, nickel and cobalt are the classic magnetic metals; that is why a fridge magnet sticks to a steel door but not to a soda can.
Q 24Which four states of matter can you see in everyday life?
Solid, liquid, gas and plasma
Solid, liquid, gas and plasma are the four classic states of matter. Plasma is the surprising one: lightning and the glow inside a neon sign are both plasma.
Q 25When 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 26Water vapor turning back into liquid drops on the outside of a cold glass is an example of what?
Condensation
Condensation is water vapor turning back into liquid when it meets a cold surface. Clouds form the same way: air cools to its dew point and the invisible vapor becomes tiny visible droplets.
Q 27Clouds are made mostly of what?
Tiny water droplets and ice crystals
Clouds are made of tiny water droplets and ice crystals, so light that they hang in the air; a plane can fly straight through one, and fog is simply a cloud sitting on the ground.
Q 28What is the lowest layer of Earth's atmosphere, where most weather happens, called?
The troposphere
The troposphere is the lowest layer of the atmosphere, only about 10 to 15 km thick, yet nearly all clouds, rain and storms happen inside it.
Q 29Which part of the upper atmosphere soaks up most of the Sun's harmful ultraviolet light?
The ozone layer
The ozone layer, high in the stratosphere, absorbs most of the Sun's ultraviolet light. French physicists Charles Fabry and Henri Buisson discovered it in 1913, and the 1987 Montreal Protocol phased out the chemicals thinning it.
Q 30Which 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.