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60 free Easy Science trivia questions with answers — science & nature quiz, new questions added Aug 2026.
Fifty free easy science trivia questions with answers, written so that anyone from a curious ten-year-old to an adult who last took a science class decades ago can score well and learn something. It covers space (which planet is biggest, who walked on the Moon first), the human body (how many bones, which organ is largest), animals (the fastest, the biggest, the only flying mammal), everyday chemistry (what water is made of, gold's symbol) and the scientists behind gravity, evolution, penicillin and relativity. These are science trivia easy questions, not trick questions: every one has a single clear answer that most people half-remember, plus a short explanation that adds one thing worth knowing. Use it as a warm-up round for a family quiz night, a classroom starter or a quick solo game. Every answer is checked against encyclopaedia and reference sources, so the numbers are right even when the questions are simple.
30 of 60 questions with answers and explanations. Play the quiz
Q 01Which is the largest planet in the Solar System?
Jupiter
Its radius is about 71,000 km, and it sits 5.2 astronomical units from the Sun.
Q 02Which is the smallest planet in the Solar System, and the closest to the Sun?
Mercury
It orbits between 0.31 and 0.59 astronomical units from the Sun, so its year lasts only 88 Earth days.
Q 03Roughly what share of the Solar System's total mass is the Sun?
About 99.9%
Everything else, including all the planets, adds up to well under one percent.
Q 04The asteroid belt lies between the orbits of which two planets?
Mars and Jupiter
The dwarf planet Ceres, the largest object in the belt, lives there too.
Q 05Earth's atmosphere is made up mostly of oxygen and which other gas?
Nitrogen
That gas makes up about four-fifths of the air, with oxygen just under 21%.
Q 06Which metal makes up most of Earth's core?
Iron
The core is nearly 89% of that metal, with nickel and sulfur making up most of the rest.
Q 07The red-orange colour of the surface of Mars is caused by which compound?
Iron oxide
In other words, the planet is rusty; it is also home to two small potato-shaped moons, Phobos and Deimos.
Q 08How many natural satellites, or moons, does Mars have?
Two
Both are small and irregular in shape, unlike Earth's large, round Moon.
Q 09What is the Sun?
A star
It formed about 4.6 billion years ago and its diameter is roughly 109 times that of Earth.
Q 10The Sun's core produces energy by fusing hydrogen into which element?
Helium
About 600 billion kilograms of hydrogen are converted every second.
Q 11Who was the first person to walk on the Moon?
Neil Armstrong
He stepped out about six hours after landing on July 20, 1969, with Aldrin following nineteen minutes later.
Q 12What was the name of the Apollo 11 lunar module that landed on the Moon?
Eagle
The name came from the bird on the mission patch, while the command module that stayed in orbit was called Columbia.
Q 13How many people had walked on the Moon by the end of the Apollo programme in 1972?
Twelve
Six missions landed, and the longest stays lasted up to three days.
What is the main cause of the ocean tides on Earth?
Q 21What is the largest organ of the human body?
The skin
It accounts for roughly 16% of body mass.
Q 22How many chambers does the human heart have?
Four
Two upper atria and two lower ventricles, beating close to 72 times a minute at rest.
Q 23Roughly what percentage of an adult human body is water?
About 60%
For an adult man that works out at around 42 litres.
Q 24What does DNA stand for?
The Moon's gravity
The same tidal pull has locked the Moon so that it always shows Earth the same face.
Q 15What is the chemical formula for water?
H2O
Two hydrogen atoms bonded to one oxygen atom; it is the only common substance found naturally as solid, liquid and gas on Earth.
Q 16At what temperature does water boil at sea level?
100 °C
That is 212 °F; at the other end, it freezes at 0 °C (32 °F).
Q 17Roughly what fraction of Earth's surface is covered by water?
About 71%
The seas and oceans hold about 96.5% of all that water.
Q 18What happens to the volume of water when it freezes into ice?
It expands
It grows by about 9%, which is why ice floats and why frozen pipes burst.
Q 19What is the green pigment that plants use to absorb light?
Chlorophyll
It reflects the green part of the spectrum rather than absorbing it, which is why most plants look green.
Q 20About how many bones does an adult human skeleton have?
206
Babies start with around 270, but many fuse together as we grow.
Deoxyribonucleic acid
Its two strands coil around each other in the famous double helix described by Watson and Crick in 1953.
Q 25How many legs does an insect have?
Six
Three pairs of jointed legs on a three-part body; insects are the most diverse animal group, with over a million described species.
Q 26How many limbs does a spider have?
Eight
That extra pair is one reason spiders are arachnids, not insects; they spin silk from spinnerets on the abdomen.
Q 27What is the fastest land animal?
Cheetah
The highest reliably recorded speed is 104 km/h (65 mph), fast enough to catch antelope with a big head start.
Q 28What is the largest animal known to have ever existed?
Blue whale
It can reach around 30 metres in length and weigh up to 200 tonnes.
Q 29Which is the tallest living land animal?
Giraffe
Its neck has the same number of vertebrae as most mammals; each one is simply stretched to over 28 cm.
Q 30What is the largest living bird?
Ostrich
It cannot fly, but it can run at 70 km/h and lays the biggest eggs of any living land animal.