50 Science Riddles That Will Leave You Scratching Your Head

Danielle Outen
May 17, 2024 By Danielle Outen
Originally Published on Sep 29, 2020
Fact-checked by Isobel Murphy
Librarian helping a girl.

Getting the family to solve science riddles and brain teasers is an exciting and educational activity.

Encouraging kids to solve science riddles as well as trying trivia is a great way to get them to think outside of the box.. Science riddles can also help kids remember important science facts - it's a no brainer!

Here we have the 50 best science riddles with answers that you and your kids would love. We have categorized our science riddles under biology, chemistry, and physics. Happy riddle-ing!

Physics Riddles

Science riddles are always a brilliant way to nurture little Einsteins. Here are the best Physics riddles to blow your mind.

1. Many have heard it, but nobody has ever seen it. It will not speak back unless spoken to. What is it? An echo.

2. I am a rock bigger than Venus but smaller than Uranus. What am I? Earth.

3. You cannot see me, I cannot be touched, you cannot feel me but I can cook your lunch. What am I? A microwave particle.

4. What is the center of gravity? The letter "V".

5. I was once a massive star and soon I will be a brightly colored gas cloud. For now, I am a massive explosion. What am I? A Supernova.

6. What is a Priest's favorite part about Physics? Mass.

7. What planet has the shortest year? Mercury, as it is closest to the Sun.

8. Which is heavier, a pound of feathers or a pound of bricks? They both weigh the same.

9. I have been around for millions of years but am only a month old. What am I? The moon.

10. What is full of holes but still holds water? A sponge.

11. What period of time weighs the least? A light-year.

12. I am the hottest body in the solar system and I keep everyone warm. Who am I? The Sun.

13. I am three-quarters of the universe and almost nothing is known about me. What am I? Dark matter.

14. I can rush, I can be hot, I can be cold, I can be hard, I can slip through anything. What am I? Water.

15. It is impossible for me to be created, and I can never be destroyed, I can only change form. What am I? Energy.

16. I am a tunnel, a shortcut that connects places across space and time. What am I? A wormhole.

17. You can't see me, but I can see you; To be more specific, I see through. What am I? An X-ray.

Chemistry Riddles

Rather than make a messy chemistry experiment, try one of these chemistry inspired science riddles instead.  Kids love would them as much as they love to make a mess!

18. What can eat a lot of iron without getting sick? Rust.

19. What can be measured but has no width, length or height? The temperature.

20. Give me food and I will live. Give me water and I will die. What am I? Fire.

21. What are the only two periodic elements to have a liquid state? Bromine and Mercury.

22. What periodic element do pyromaniacs love the most? Arsenic.

23. I am a gas and line-up with neon. I am also the home of a superhero. What am I? Krypton.

24. What chemical element doesn't like to follow? Lead.

25. I am hard as a rock but when put in hot water, I immediately melt. What am I? An ice cube.

26. What is black when you buy it, red when you use it, and gray when you throw it away? Charcoal.

27.What two periodic elements when combined heal? Helium and aluminum (HE + AL)

28. I am a god, a planet, and can measure heat. What am I? Mercury.

29. Occasionally associated with smelly things, what state of matter am I? Gas.

30. You have a glass of milk and a glass of water. You need to pour them into the same container such that the two liquids are differentiated and can be separated. How do you do it? Pour in the water, freeze it, then pour in the milk.

Young girl reading a book.

Biology Riddles

These biology themed science riddles are a fantastic way to encourage your kids to love science.

31. What are the three R's that keep our planet clean? Reuse, recycle, reduce.

32. I am a gas that helps plants but cannot be bought at the gas station. What am I? Carbon Dioxide.

33. I am hard like stone but you can find me on the body. What am I? Teeth

34. What animal lives longest in zoos? Turtles.

35. What are ten things you can always count on? Your fingers.

36. What do dogs have that no other animal has? Puppies.

37. What can you hold no longer than a few seconds? Your breath.

38. I was once an embryo but have now gone through eight weeks of development. What am I? A fetus.

39. I am under your face and outside your mind. What am I? Your skull.

40. I am needed for flight but cannot fly on my own. What am I? Feathers.

41. I like to roam but always stay home. If you carried what I carried you'd break your back. What am I? A snail.

42. I can be good for you, I can be bad. You can find me all over your body. What am I? Bacteria.

43. I'm excellent to taste but horrible to smell. What am I? Tongue.

44. What is neither water nor land but is always soaking wet? Wetlands.

45. Each of your parents gave you twenty-three threadlike strands that made you who you are today. What are they? Chromosomes.

Maths Riddles

Mathematics is not exactly a science, but science would be nothing without it! Here are the best maths themed science riddles that we could find.

46. How many sides does a circle have? Two, an inside and an outside.

47. Two hens lay two eggs every two minutes. What is the total number of hens to lay 500 eggs in 500 minutes? Two hens.

48. If you take four years, how many days are there altogether? 1461, (365 x 4) + 1 because of the leap year.

49. I am four times as old as my son. In 20 years time I shall be twice as old as him. How old are we now? I am 40 my son is 10.

50. If I am 90cm plus half my height, how tall am I? 180cm.

If you would like to read some other amazing riddle articles after Science Riddles, you can check out water riddles.

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Written by Danielle Outen

Bachelor's degree specializing in Economics, Master's degree specializing in Development Management

Danielle Outen picture

Danielle OutenBachelor's degree specializing in Economics, Master's degree specializing in Development Management

Growing up in London, Danielle has a Bachelor's degree in Economics from the University of Southampton and a Master's degree in Development Management from the London School of Economics and Political Science (LSE). She has always been surrounded by a big family and loves outdoor activities and adventurous experiences. She has traveled the world in search of new waves to surf. Danielle enjoys discovering new and fun activities to share with her relatives.

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Fact-checked by Isobel Murphy

Bachelor of Arts specializing in History

Isobel Murphy picture

Isobel MurphyBachelor of Arts specializing in History

With a love for exploring cities and finding outdoor spaces to enjoy, Isobel has spent her life exploring various cities in the UK, from her hometown of Surrey to Birmingham where she studied history for three years. She is passionate about sports and enjoys watching and playing, as well as baking and spending quality time with her loved ones.

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