161 Science Riddles With Answers - page 2 of 2
Next element in: H, Be, F, S, Mn, Kr, In, Gd, Tl?
This sequence follows the atomic numbers (1, 4, 9, 16, 25...) which are perfect squares. The next is 92 (Uranium).
How many bounces will it take for a ball to stop?
In a theoretical model with a restitution coefficient, the ball bounces infinitely many times with decreasing height.
Why did Andrew die after mopping bleach with a rag and fluid?
Mixing bleach with ammonia-based cleaners creates toxic chloramine gas, which is lethal.
If you hammer a nail into a tree, where is it 5 years later?
Trees grow from the top (apical meristems), so a nail in the trunk stays at the same height.
How much more powerful is an earthquake 0.5 higher on the scale?
The Richter scale is logarithmic; an increase of 0.5 corresponds to about sqrt(10) or 3.16 times the energy.
The beginning of the end, as well as the end of time and space.
This is a word riddle; the letter 'E' is the start of 'End' and the last letter of 'time' and 'space'.
I'm sometimes full, but I never overflow.
The Moon goes through phases, including a 'Full Moon,' but it is a solid celestial body.
At night they come without being fetched, by day they are lost.
Stars are always there but only become visible to us when the sun goes down.
I make up almost of the universe, but no one knows about me.
Dark energy is a mysterious force driving the universe's expansion, making up ~68% of it.
I am a god, I am a planet, and I can measure the temperature.
Mercury is a Roman god, the closest planet to the sun, and the liquid used in thermometers.
If you give it food, it'll live if you give it water, it will die.
Fire requires fuel (food) to burn but is extinguished by water.
What has a mouth but can't chew?
A river has a 'mouth' where it meets the sea, but obviously cannot chew anything.
What goes around the wood but never goes into the wood?
The bark is the outermost layer that surrounds the trunk but doesn't enter the interior wood.
What is neither water nor land but is always soaking wet?
Wetlands are areas where water covers the soil, creating a unique, soggy ecosystem.
Born in the ocean and white as snow; disappears in water.
Salt is harvested from the sea and dissolves (disappears) when put back into water.
What four elements make up something that terrifies criminals?
The symbols for Carbon (C), Oxygen (O), Phosphorus (P), and Sulfur (S) spell 'COPS'.
Benzene ring with iron atoms replacing carbon atoms?
A 'Ferrous Wheel' is a pun on 'Ferris Wheel' and the chemical term for iron (ferrous).
I am a unit of chemical elements, but I can never be trusted. Why?
A pun on 'Atoms' (the unit) 'making up' (inventing) things and being the fundamental building blocks of matter.
I come as a gas, and I'm in line with Neon. Home of a Super man.
Krypton is a noble gas in the same group as Neon, and also the name of Superman's home planet.
What number do Nickel and Neon make when they are combined?
The chemical symbols Ni (Nickel) and Ne (Neon) spell 'NiNe'.
Which element is derived from a Norse god?
Thorium is named after Thor, the Norse god of thunder.
What do you do with a dead chemist?
This is a classic pun riddle -- "barium," the chemical element, sounds just like "bury 'em," which is exactly what you'd do with the deceased chemist.
Which two elements heal?
A pun on the symbols He and Al, which spell 'Heal'.
Black when you get it, red when you use it, grey when you are finished.
Charcoal is black, glows red when burning, and turns into grey ash when consumed.
What chemical doesn't like to follow?
A pun: 'Lead' is a metal, but the word 'lead' also means to be at the front or guide others.
What can eat a lot of iron without getting sick?
Rust (iron oxide) forms when iron reacts with oxygen and water, essentially 'consuming' the metal.
I am the equivalent of a one-way street in the universe. What am I?
Time only moves in one direction�forward�according to the second law of thermodynamics.
What period of time is the lightest/weighs the least?
Wordplay: A 'day' can be 'light' (daylight), unlike the night.
Which concept in physics is the loneliest?
A singularity is a point of infinite density, often described as 'one' or unique in space-time.
What goes up and down without moving?
Temperature readings on a thermometer rise and fall without the device itself moving.
You can find me in Mercury, Earth, Mars, and Jupiter. But not Neptune or Venus.
This is a wordplay riddle; the letter 'R' appears in the names of the first four mentioned planets but not the others.
You can't see me but I can see you. I can see right through.
X-rays have high energy and can pass through soft tissues but not bones, making them useful for imaging.
It is very hard to create me, but I can't be destroyed. I can only change form.
The Law of Conservation of Energy states energy cannot be created or destroyed.
I can be hot, cold, hard, and go through anything. What am I?
Water can be steam (hot), ice (hard/cold), and flow through various substances.
Which is heavier, a ton of feathers or a ton of rocks?
A ton is a measure of weight, so 2000 lbs of anything weighs exactly the same.
What is the center of gravity?
This is a wordplay riddle; the letter 'v' is the literal middle letter of the word 'gravity'.
You can't see me, I can't be touched... but I cook your lunch. What am I?
Microwaves are electromagnetic waves that vibrate water molecules to generate heat.
Lots of people have heard it, but no one has seen it. It will not speak back unless spoken to.
An echo is a reflection of sound that returns to the source after a delay.
When liquid splashes me, none seeps through; when I am hit, I change color. What am I?
Skin is waterproof and bruises (changes color) when struck or injured.
I am a ball that can be rolled, but never bounced or thrown. What am I?
An eyeball is spherical and rotates (rolls) in the socket but cannot be bounced.
One monkey has a banana, one a stick, one nothing. Which primate is the smartest?
Humans are primates, and you (the person answering) are the smartest primate in this scenario.
Your mom and dad each gave you 23 of these threadlike strands. What are they?
Humans have 23 pairs of chromosomes, one set from each parent.
What grows only upwards and can never come down?
Height refers to the measurement of how tall something is, which increases as you grow.
I can be good for you, but I can also be bad for you, and you will find me wherever you go. What am I?
Bacteria exist everywhere; some are beneficial (probiotics) while others cause disease.
I'm great at tasting but horrible at smelling. What am I?
The tongue contains taste buds but does not have olfactory (smell) receptors.
I love to roam, but I always stay home. If you carried what I carried, you'd end up breaking your back! What am I?
A snail carries its heavy shell everywhere it goes as its home.
I am under your face and outside your mind. What am I?
The skull protects the brain (mind) and is located beneath the facial features.
I am needed for flight but cannot fly on my own. What am I?
Feathers provide lift and insulation but require a bird's movement to fly.
I am hard as a stone but you can find me on your body. What am I?
Teeth are the hardest substance in the human body, similar to stone.
What can you hold for no longer than a few seconds, even without your hands?
You can only hold your breath for a short time before needing to inhale.
What are 10 things that you can always count on?
A play on words; you use your fingers to count numbers.
I am a gas that is essential for plants but I can't be bought at the gas station. What am I?
Plants use Carbon Dioxide for photosynthesis to produce food.
Nobody empties me, but I never stay full for long. What am I?
The moon cycles through phases, changing how full it looks.
I have no wings, but I can fly. And I have no eyes, but I can cry. What am I?
A cloud moves in the sky (flies) and produces rain (cries).
I have storms that rage for hundreds of years. My winds are the fastest. What am I?
The blue planet known for the Great Dark Spot and extremely high winds.
I'm closest to the Sun, but I don't get much attention. What am I?
The planet closest to the Sun's intense heat.
I'm red all over, with dust in the air. What am I?
The Red Planet known for its dusty and iron-rich surface.
I'm your home and the third from the Sun. What am I?
Our planet is the third from the Sun in our solar system.
I'm hot and bright, but don't touch! I shoot up from the Earth in a big rush. What am I?
A mountain that erupts with hot lava.
I live in the sky but fall to the ground. I'm cold and white and make no sound. What am I?
Frozen precipitation that falls silently from the sky.
I'm not alive, but I can grow. I don't have lungs, but I need air. What am I?
Fire consumes oxygen (needs air) and spreads (grows).