Thirty questions on the planets, the animal world, the human body and everyday chemistry. Answers that depend on new discoveries, like moon counts, are dated so they don't go stale silently.
Jupiter is more than twice as massive as all the other planets combined. About 1,300 Earths would fit inside it.
Question 2
How many planets are in our solar system?
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Eight
The International Astronomical Union reclassified Pluto as a dwarf planet in 2006, leaving eight planets.
Question 3
Which planet is known as the Red Planet?
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Mars
Iron oxide, essentially rust, in Martian dust and rock gives the planet its reddish color.
Question 4
Which gas do plants take in from the air to make food by photosynthesis?
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Carbon dioxide
Plants combine carbon dioxide and water using sunlight to make sugar, releasing oxygen as a by-product.
Question 5
What is the chemical formula for table salt?
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NaCl
Table salt is sodium chloride: one sodium atom (Na) for every chlorine atom (Cl).
Question 6
About how fast does light travel in a vacuum?
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About 300,000 km per second
The exact figure is 299,792,458 meters per second, which works out to about 186,000 miles per second.
Question 7
Which part of a cell is often called its powerhouse?
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Mitochondria
Mitochondria produce most of the cell's chemical energy in the form of ATP.
Question 8
How many bones are in the adult human body?
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206
Babies are born with around 300 bones and cartilage pieces; many fuse during growth, leaving 206 in most adults.
Question 9
What is the largest animal that has ever lived, as far as we know?
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Blue whale
Blue whales reach about 30 meters long and can weigh more than any dinosaur known from fossils.
Question 10
Which is the fastest land animal?
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Cheetah
Cheetahs can top 100 km/h (over 60 mph) in short sprints. The pronghorn is slower but can keep up a high speed for much longer.
Question 11
How many hearts does an octopus have?
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Three
Two hearts pump blood through the gills and one pumps it to the rest of the body. Their blood is blue because it uses copper-based hemocyanin.
Question 12
What is the closest star to Earth?
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The Sun
The Sun is a star about 150 million km away. The next nearest, Proxima Centauri, is about 4.2 light-years away.
Question 13
As of 2025, which planet has the most confirmed moons?
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Saturn
In 2025 astronomers confirmed 128 more moons of Saturn, bringing its count to 274. Jupiter is second.
Question 14
Which element has the atomic number 1?
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Hydrogen
Hydrogen has one proton. It is the lightest element and the most abundant in the universe.
Question 15
Who published the general theory of relativity in 1915?
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Albert Einstein
General relativity describes gravity as the curving of space and time by mass. Einstein's special relativity came first, in 1905.
Question 16
What kind of animal is a Komodo dragon?
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A lizard
It is the largest living lizard, reaching about 3 meters, and lives on a few Indonesian islands.
Question 17
Which blood cells are the main defense against infection?
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White blood cells
White blood cells find and destroy germs. Red cells carry oxygen, and platelets help blood clot.
Question 18
Which is the only mammal capable of true, powered flight?
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The bat
Flying squirrels, sugar gliders and colugos glide. Bats flap their wings and fly.
Question 19
About how long does sunlight take to reach Earth?
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About 8 minutes
At about 150 million km, light from the Sun takes roughly 8 minutes and 20 seconds to arrive.
Question 20
What does DNA stand for?
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Deoxyribonucleic acid
DNA carries genetic instructions. James Watson and Francis Crick described its double helix in 1953, using Rosalind Franklin's X-ray data.
Question 21
Which planet has the hottest surface?
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Venus
Mercury is closer to the Sun, but Venus's thick carbon dioxide atmosphere traps heat, keeping its surface around 465°C.
Question 22
Which pigment makes plants green?
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Chlorophyll
Chlorophyll absorbs red and blue light for photosynthesis and reflects green, which is the color we see.
Question 23
Which is the largest living bird?
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Ostrich
Ostriches can stand about 2.7 meters tall. They can't fly but can run at around 70 km/h.
Question 24
Which metal is liquid at room temperature?
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Mercury
Mercury melts at −38.8°C. Gallium melts just above room temperature, at about 30°C.
Question 25
Who was the first American in space?
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Alan Shepard
Shepard flew Freedom 7 on May 5, 1961, a 15-minute suborbital flight. John Glenn was the first American to orbit Earth, in 1962.
Question 26
What is the scientific study of earthquakes called?
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Seismology
Seismologists measure earthquakes with seismometers. Seismos is Greek for a shaking.
Question 27
How many chambers does the human heart have?
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Four
Two atria receive blood and two ventricles pump it out, one side to the lungs and the other to the body.
Question 28
What is a group of lions called?
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A pride
Lions are the most social big cats. A pride is usually a few related females, their cubs and one or more males.
Question 29
What is the boiling point of water at sea level in degrees Celsius?
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100°C
The Celsius scale was built around water: 0° for freezing and 100° for boiling at sea-level pressure. Water boils at lower temperatures at altitude.
Question 30
Which planet spins in the opposite direction to most planets, so the Sun rises in the west?
Show answer
Venus
Venus rotates backward, and slowly: one rotation takes about 243 Earth days, longer than its 225-day year.
Key numbers
Questions
30
Format
Multiple choice, 4 options
Explanations
Every question
Answers
Hidden until you open them
Space questions
A third of this set is about the solar system, from the easy (the Red Planet) to the ones that catch people out, like the closest star (it's the Sun) or the hottest planet (Venus, not Mercury). Moon counts keep changing as telescopes find more, so that question says "as of 2025" and we update it when NASA's count changes.
Animals and the body
Animal questions favor surprising facts with a clear answer: the octopus's three hearts, the only mammal that truly flies, the largest bird. Human-body questions stick to textbook facts, such as 206 bones and four heart chambers, and say where children and adults differ.
Why some explanations add a second fact
A good science answer should leave you knowing slightly more than the question asked. So when the answer is "cheetah," the explanation adds that the pronghorn can keep up a fast pace for much longer. If you host, that second fact is your follow-up line, and it often starts the best arguments of the night.
For more space detail, see the planets in order. For surprising facts about animals and space in shorter form, browse the fun facts.
Questions people ask
Are these science trivia questions suitable for a family game?
Yes. They avoid anything graphic and stick to school-level science. Children may need the four options; adults can try them without.
Why does the moons question say 'as of 2025'?
Astronomers keep confirming new moons, especially around Saturn and Jupiter. Dating the question keeps it honest; we update it when NASA's official count changes.
Where do the science answers come from?
Each answer was checked against NASA, a natural history museum or a standard reference. The sources are listed at the bottom of this page.