Space & Cosmos
How Do Black Holes Die? The Slow Fade of the Darkest Things
How do black holes die? Through Hawking radiation, they slowly evaporate over almost unimaginable spans of time. Here's how the universe's darkest objects end.
A library of wonder. Clear, accurate answers to the questions about space, life on Earth, and the science of you that you keep meaning to look up.
Space & Cosmos
How Big Is the Universe? (And Does It Have an Edge?)
How big is the universe? The observable universe spans 93 billion light-years, but the whole thing may be infinite. Here's what 'size' even means in space.
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New? Three good places to begin.
Life on Earth
How Deep Is the Ocean? (And What Lives at the Very Bottom)
How deep is the ocean? The deepest point plunges nearly 7 miles down. Here's what the journey looks like, and the astonishing life waiting in the dark.
The Science of Us
What Causes Déjà Vu? The Science Behind That Eerie Feeling
What causes déjà vu, that sense you've lived this moment before? Leading brain science points to a memory 'misfire.' Here's the most likely explanation.
Space & Cosmos
For the questions that make the room feel bigger.
Space & Cosmos
How do astronauts sleep in space?
How do astronauts sleep in space? Zipped in wall-strapped bags through 16 daily sunrises, with masks, earplugs, and, a 2014 Lancet study found, sleep meds.
Space & Cosmos
Can you see the Milky Way with the naked eye?
Can you see the Milky Way with the naked eye? Yes, under dark skies, but light pollution hides it from ~80% of North Americans. Here's how and where to look.
Space & Cosmos
Can you see the Moon during the day? Yes, almost daily
Can you see the Moon during the day? Yes, on most days of the month. It's bright enough to show against the blue when it's clear of the Sun's glare.
Space & Cosmos
How Many Moons Does Jupiter Have? The Count Keeps Climbing
How many moons does Jupiter have? NASA recognizes 101 officially, and the latest catalog lists 115 as of April 2026. Here is why the number keeps rising.
Space & Cosmos
What would happen if you fell into a black hole?
In an idealized quiet system, a small black hole can shred you before the horizon, while a supermassive one may let you cross before tides become lethal.
Space & Cosmos
What is the temperature on the moon? From boiling to deep freeze
What is the temperature on the moon? It swings from about 120 C in daylight to -130 C at night, with polar craters near -240 C, because the Moon has no atmosphere.
Space & Cosmos
Why do we have seasons? It's the tilt, not the distance
Why do we have seasons? Earth's axis is tilted about 23.5 degrees, so each hemisphere leans toward the Sun for half the year. It's the tilt, not the distance.
Space & Cosmos
How Old Is the Universe? 13.8 Billion Years, and How We Know
How old is the universe? About 13.8 billion years, measured from the oldest light in the sky and the rate at which the cosmos is still expanding.
Space & Cosmos
Why is Venus the hottest planet? Not the one closest to the Sun
Why is Venus the hottest planet when Mercury sits closer to the Sun? A runaway greenhouse effect and thick carbon dioxide trap the heat with nowhere to go.
Space & Cosmos
What would happen if the Sun disappeared? Minute by minute
What would happen if the Sun disappeared? For 8 minutes, nothing. Then darkness, Earth flung into space, and a slow freeze. Here is the full timeline.
Space & Cosmos
How big is the sun compared to earth? 109 across, a million inside
How big is the sun compared to earth? About 109 times wider, big enough to swallow 1.3 million Earths, and holding 99.8% of all the mass in the solar system.
Space & Cosmos
How do astronauts poop in space? Very carefully, with a lot of airflow
How do astronauts poop in space? With airflow, not gravity. NASA's toilet suctions waste away, recycles urine into drinking water, and burns the rest up.
Space & Cosmos
How long would it take to get to the moon? From 1.3 seconds to over a year
How long would it take to get to the moon? About 3 days like Apollo, 8.5 hours at the fastest flyby, or 14 months by ion engine. It all depends on how you travel.
Space & Cosmos
What Is a Shooting Star? Not a Star at All, Just a Speck Burning Up
What is a shooting star? Not a star at all. It's a meteoroid, often a grain of dust or a pebble, burning up about 75 to 120 km overhead as it hits the air.
Space & Cosmos
Why is the moon moving away from earth? Blame the tides
Why is the moon moving away from earth? Tidal friction nudges it 3.8 cm farther each year, the speed your fingernails grow, while slowly stretching out our days.
Space & Cosmos
What are Saturn's rings made of? Mostly ice, and they are vanishing
What are Saturn's rings made of? Over 95 percent water ice, from dust grains to house-sized boulders, and they are young, thin, and slowly raining away.
Space & Cosmos
How Loud Would the Sun Be If We Could Hear It? Around 100 dB
How loud would the sun be if we could hear it? Estimates put it near 100 dB at Earth, about a rock concert, but space is a vacuum so the sound never arrives.
Space & Cosmos
What Is a White Hole? Real Math That Nature Never Built
What is a white hole? It is a black hole with time reversed: a region nothing can enter. Real math, badly unstable, and never once seen in the sky.
Space & Cosmos
Is the Universe Infinite? Space Is Flat, and That Settles Nothing
Is the universe infinite? Space measures flat to within a fraction of a percent, which permits an endless cosmos but cannot prove one. Here's why.
Space & Cosmos
Why is Mars red? It is rusting, and that is a clue to its watery past
Why is Mars red? The planet is coated in iron oxide dust, the same stuff as rust. A 2025 study points to a water-bearing mineral, hinting Mars was once wet.
Space & Cosmos
How Big Is the Biggest Star Compared to the Sun? Up to 2,000+ Times Wider
How big is the biggest star compared to the sun? The largest known stars are roughly 1,500 to 2,100+ times the Sun's radius, big enough to swallow the inner planets.
Space & Cosmos
What Would Happen If the Moon Crashed Into Earth? It Would Shatter First
What would happen if the moon crashed into earth? It would break apart into a ring long before impact, when it crossed Earth's Roche limit. And it can't happen.
Space & Cosmos
How Long Would It Take to Drive to the Sun? About 177 Years
How long would it take to drive to the sun? At a steady 60 mph nonstop, about 177 years. Light makes the same trip in 8 minutes, and one NASA probe in 9 days.
Space & Cosmos
What Is on the Other Side of a Black Hole? Honestly, Nobody Knows
What is on the other side of a black hole? Likely a singularity we can never see, while white holes and wormholes stay math, not proof. Here is the honest answer.
Space & Cosmos
How Many Earths Can Fit in the Sun? About 1.3 Million
How many earths can fit in the sun? About 1.3 million by volume, or roughly 960,000 packed as solid spheres, with 109 lined up across its face.
Space & Cosmos
How cold is space? Colder than almost anywhere, but not how you think
How cold is space? Empty space sits at about -270C, just above absolute zero. But a vacuum has no real temperature, and you would overheat before you froze.
Space & Cosmos
What does space smell like? Astronauts say seared steak
What does space smell like? Astronauts describe seared steak, hot metal, and gunpowder clinging to suits after spacewalks. Here is the chemistry behind it.
Space & Cosmos
Why is Pluto not a planet? The vote that demoted a world
Why is Pluto not a planet? In 2006 astronomers voted it a dwarf planet for failing one rule: it never cleared its orbit. The story, and the man who killed it.
Space & Cosmos
Where Does Gold Come From? The Cosmic Catastrophe Behind Every Wedding Ring
Where does gold come from? The gold in your jewelry was forged in a neutron star collision billions of years ago. Here's the wild physics behind it.
Space & Cosmos
What Happens When the Sun Dies?
What happens when the sun dies? In 5 billion years it swells into a red giant, swallows the inner planets, and fades to a white dwarf. Here's the timeline.
Space & Cosmos
Why Do Stars Twinkle but Planets Don't?
Why do stars twinkle while planets shine steadily? The answer is our turbulent atmosphere bending starlight, and a surprising trick of distance and size.
Life on Earth
For nature's cleverest and most unlikely tricks.
Life on Earth
How a Venus flytrap works: it counts to two
How does a Venus flytrap work? It counts touches on its trigger hairs, normally snapping shut after two within roughly 20 to 30 seconds and digesting only after about five.
Life on Earth
How long can penguins hold their breath? Past twenty minutes
How long can penguins hold their breath? Emperor penguins usually dive 3 to 6 minutes, but the longest dive on record ran 27.6 minutes on a single breath.
Life on Earth
Why do horses sleep standing up? Locked legs, fast escape
Why do horses sleep standing up? A built-in 'stay apparatus' helps stabilize selected leg joints so they can doze upright and stay ready to move. But they must lie down to dream.
Life on Earth
Why did woolly mammoths go extinct? The answer is still being argued
Why did woolly mammoths go extinct? A warming climate shrank their habitat and humans hunted them, and the last island survivors may have died from a fluke.
Life on Earth
Why do turtles live so long? They barely age
Why do turtles live so long? A slow metabolism, a protective shell, and a trait called negligible senescence: many barely age, their death risk barely rises.
Life on Earth
Why do cats eyes glow in the dark? They're handing your light back
Why do cats eyes glow in the dark? A mirror behind the retina, the tapetum lucidum, bounces light back for a second look. Their eyes reflect light, not make it.
Life on Earth
Were Dinosaurs Warm Blooded? It Depends Which Dinosaur
Were dinosaurs warm blooded? Some ran as hot as birds while others stayed cool like reptiles. Here is what fossil bone chemistry actually reveals today.
Life on Earth
Why do snakes shed their skin? Because it can't grow with them
Why do snakes shed their skin? Their outer layer can't grow, so they replace it whole, peeling off inside out like a sock, eye caps and all. Here's how it works.
Life on Earth
How do jellyfish sting? Millions of microscopic harpoons
How do jellyfish sting? Their tentacles carry microscopic cells that sense contact, fire barbed threads, and deliver venom in one of biology's fastest cellular events.
Life on Earth
How fast do hummingbirds flap their wings? It depends on the species
How fast do hummingbirds flap their wings? Many beat 40 to 80 times a second, while the smallest species can top 100. Here is how they hover.
Life on Earth
Why do frogs croak? A males-only love song
Why do frogs croak? Mostly male frogs call to attract mates and warn off rivals, using a balloon-like vocal sac to amplify a song unique to their species.
Life on Earth
How strong are ants, really? The numbers and the physics
How strong are ants? A controlled study clocked leafcutters at about 9 times their body weight, and a neck joint held up to 5,000. What the figures mean.
Life on Earth
How do starfish eat? They push their stomach out through their mouth
How do starfish eat? A starfish pries open a clam, pushes its own stomach out through its mouth into the shell, and digests the animal alive, outside its body.
Life on Earth
How do fish breathe underwater? The genius of gills
How do fish breathe underwater? Gills pull dissolved oxygen from water using countercurrent exchange, grabbing up to 90 percent of it.
Life on Earth
Why do giraffes have long necks? Science isn't sure
Why do giraffes have long necks? The textbook answer, reaching high leaves, is actually contested, and a rival idea says the neck is a weapon for male combat.
Life on Earth
Why do dogs have wet noses? It's how they smell, cool down, and sense heat
Why do dogs have wet noses? The moisture traps scent so they smell better and helps them cool off, and the cold tip can even sense a warm body's heat across a room.
Life on Earth
Why do beavers build dams? It's a moat, not a house
Why do beavers build dams? To flood a deep pond that guards them from predators and keeps food reachable under winter ice. The trigger is a sound.
Life on Earth
Why do dogs lick you? It's more than kisses
Why do dogs lick you? It's not just kisses. Licking is inherited affection, feel-good endorphins, a taste of salt on your skin, and a bid for attention.
Life on Earth
Do ants have brains? Yes, and the colony has a bigger one
Do ants have brains? Yes, each ant has a real brain with tens of thousands of neurons. But the colony's true intelligence lives somewhere stranger.
Life on Earth
Why do dogs bury bones? The wolf in the backyard
Why do dogs bury bones? It's an inherited caching instinct from wolf ancestors who hid surplus food for lean times. Pet dogs do it even when they're well fed.
Life on Earth
Why do bats hang upside down? A launchpad and a lock
Why do bats hang upside down? They can't take off from the ground, so they roost high and drop into flight, and a tendon lock lets them hang for free.
Life on Earth
Why do cats knock things over? It's a hunt, not spite
Why do cats knock things over? A mix of hunting instinct, paws built to test 'prey,' and the fact that it reliably gets your attention. It is not spite.
Life on Earth
Why are moths attracted to light? Nobody is quite sure
Why are moths attracted to light? Science still isn't sure. A 2024 study found they tilt their backs to the glow and get trapped circling it, not flying at it.
Life on Earth
Why Don't Woodpeckers Get Headaches? Their Brains Are Tiny
Why don't woodpeckers get headaches? Not from built-in shock absorbers. Their heads work like stiff hammers, and their tiny brains stay below the injury line.
Life on Earth
How do snakes move without legs? Four hidden tricks
How do snakes move without legs? They push their flexible body against the ground and use directional belly scales, with four gaits for different terrain.
Life on Earth
Why do bees die after they sting? The barbed harpoon
Why do bees die after they sting? A honey bee's barbed stinger lodges in your skin and tears loose with its guts, but the rule is narrower than you think.
Life on Earth
Why do camels have humps? It's fat, not water
Why do camels have humps? To store fat, not water. The hump is an energy reserve that lets a camel survive long stretches without food in the desert.
Life on Earth
Why do owls hoot? A voice built for the dark
Why do owls hoot? To claim territory and attract a mate, where sound beats sight. Not every owl hoots, and the famous twit-twoo is two birds, not one.
Life on Earth
How do volcanoes erupt? It comes down to trapped gas
How do volcanoes erupt? Molten rock rises because it is light, and dissolved gas bursts out of it as the pressure drops, like a shaken can of soda.
Life on Earth
How Dark Is the Bottom of the Ocean? Total, Permanent Black
How dark is the bottom of the ocean? Below about 1,000 meters there is no sunlight at all, just permanent black, and that dark zone is most of the ocean.
Life on Earth
Why do crickets chirp? Wings, mating, and a thermometer
Why do crickets chirp? Male crickets rub their wings together, not their legs, to attract mates and warn off rivals, and the chirp rate tracks the temperature.
Life on Earth
Did dinosaurs have feathers? Many of them did
Did dinosaurs have feathers? Many did. Fossils since 1996 reveal fuzzy and fully feathered theropods, even a relative of T. rex. Birds are living dinosaurs.
Life on Earth
Why Does the Corpse Flower Smell So Bad? It Fakes Being a Dead Body
Why does the corpse flower smell so bad? It mimics rotting flesh with sulfur and amine chemicals, then heats itself to body temperature to broadcast the stench.
Life on Earth
Why does ice float? The quirk that keeps fish alive all winter
Why does ice float? Freezing locks water into an open crystal less dense than liquid, so lakes freeze top-down and life survives the winter.
Life on Earth
How do dolphins sleep without drowning? Half a brain at a time
How do dolphins sleep without drowning? They shut down one half of the brain at a time, keeping the other half awake to surface, breathe, and watch for danger.
Life on Earth
Why do flamingos stand on one leg? Two reasons, both surprising
Why do flamingos stand on one leg? To stay warm in cold water, and because it takes almost no effort, a dead flamingo can balance on one leg.
Life on Earth
Why do dogs chase their tails? From play to compulsion
Why do dogs chase their tails? Usually it's play, boredom, or a puppy meeting its own body. But frequent, frantic spinning can signal an itch or a compulsion.
Life on Earth
Why do cats hate water? Blame the desert ancestor
Why do cats hate water? Most descend from desert wildcats that never needed to swim, and wet fur turns heavy, cold, and slow to dry, leaving a cat exposed.
Life on Earth
How Do Birds Know Where to Migrate? A Stacked Toolkit
How do birds know where to migrate? With a stacked toolkit: an inherited direction, a sun compass, a star compass, a magnetic sense, landmarks, and smell.
Life on Earth
Why do dogs wag their tails? Not just because they're happy
Why do dogs wag their tails? It signals arousal, good or bad, not just joy, and they wag right when positive, left when wary. Wolves barely wag.
Life on Earth
Why do cats meow? A language they invented for you
Why do cats meow? Mostly at humans, and almost never at other cats. The meow is a near-private language cats evolved to manage us. Here is what it means.
Life on Earth
Why do dogs pant? It is how they keep their cool
Why do dogs pant? It is their main way to cool down, because they barely sweat. Panting evaporates heat off the tongue and lungs. Here is when to worry.
Life on Earth
Why do cats like boxes? Security, warmth, and ambush
Why do cats like boxes? An enclosed space lowers stress and feels safe to a predator that is also prey. Cats will even sit in a square that looks like a box.
Life on Earth
What Do Tardigrades Eat? They Stab Cells and Sip the Insides
What do tardigrades eat? Most pierce plant, algae, and moss cells with needle-like stylets and sip the fluid; some hunt rotifers and nematodes.
Life on Earth
Why do roosters crow? It's a clock, not the sunrise
Why do roosters crow? Not to greet the sunrise. An internal body clock makes them crow before dawn, and a strict pecking order decides who gets to call first.
Life on Earth
Why do bees make honey? It is winter food, not a gift for us
Why do bees make honey? It is a stored winter food the colony lives on when no flowers bloom. Here is how nectar becomes honey, and why a hive makes far extra.
Life on Earth
Why do dogs howl? An ancient phone call from the wolf
Why do dogs howl? It is long-distance communication inherited from wolves, a way of saying 'here I am.' Here is what your dog means, sirens included.
Life on Earth
Do sharks sleep? Yes, and we only just proved it
Do sharks sleep? Some do. A 2022 study caught draughtsboard sharks asleep by their metabolic rate, eyes open, most resting in bouts under ten minutes.
Life on Earth
Why do cats sleep so much? The logic behind a hunter's nap
Why do cats sleep so much? Often 12 to 18 hours a day. They are ambush predators conserving energy between hunts, and most of that sleep is light dozing.
Life on Earth
Why do cats knead? The habit that starts at the milk bar
Why do cats knead? The rhythmic paw-pushing, or making biscuits, is a comfort habit left over from kittenhood, with a scent-marking twist. Here is the science.
Life on Earth
Why do dogs eat grass? It is not because they are sick
Why do dogs eat grass? It is usually normal, not a sign of illness. The science points to an inherited instinct, and most dogs do not vomit afterward at all.
Life on Earth
How do eels reproduce? Nobody has ever seen it happen
How do eels reproduce? They spawn once in the Sargasso Sea, then die, and no one has ever seen it. Inside the 2,000-year hunt, from Aristotle to a 2022 study.
Life on Earth
How do octopuses change color in milliseconds?
How do octopuses change color? Pigment sacs, mirror cells, and a colorblind brain that matches hues it can't see, all in under a third of a second.
Life on Earth
How hard does a mantis shrimp punch?
How hard does a mantis shrimp punch? Up to 1,500 newtons at 23 m/s, with cavitation bubbles that flash light and deliver a second hit. The physics, explained.
Life on Earth
The immortal jellyfish that ages in reverse
The immortal jellyfish, Turritopsis dohrnii, rewinds its own body from adult back to a baby polyp. Here is how that escape from old age actually works.
Life on Earth
Why the Deep Sea Doesn't Crush Fish: The Physics and Chemistry of Surviving the Abyss
Why deep sea pressure doesn't crush fish comes down to water, not air, and a molecule that sets a hard chemical limit on how deep any fish can go.
Life on Earth
What Would Happen to Your Body at the Bottom of the Mariana Trench?
Would the deep sea crush you flat? Not the way movies show it. Here is what nearly 16,000 psi would really do to an unprotected human body, and why.
Life on Earth
How Do Tardigrades Survive Space? Meet the Toughest Animal Alive
How do tardigrades survive space, boiling, freezing, and radiation? These microscopic 'water bears' have a survival trick that borders on the miraculous.
Life on Earth
Why Do So Many Sea Creatures Glow? Bioluminescence Explained
Why do sea creatures glow? Bioluminescence, living light from a chemical reaction, fills the deep ocean for hunting, hiding, and luring. Here's how it works.
The Science of Us
For the odd machinery behind ordinary life.
The Science of Us
Why are some people left-handed? Honestly, we're still not sure
Why are some people left-handed? About 1 in 10 of us are. It's set before birth by many small-effect genes and chance, tied to how the brain divides its labor.
The Science of Us
Why do we blink? More than your eyes need
Why do we blink? To spread tears that keep the eye moist and clean. But we blink far more than that needs, and the extra blinks seem to punctuate how we think.
The Science of Us
Why is grass green? The color a plant throws away
Why is grass green? Chlorophyll absorbs red and blue light to power photosynthesis and reflects green to your eyes. The deeper question is why it isn't black.
The Science of Us
Why do veins look blue? Your blood was never blue at all
Why do veins look blue? Your blood is always red. Veins look blue because skin absorbs red light and scatters the rest back to your eyes. The real reason.
The Science of Us
Why do we have fingerprints? A mystery science hasn't solved
Why do we have fingerprints? They form in the womb as skin buckles into ridges, unique to you. What they are actually for is still a genuine scientific debate.
The Science of Us
Why do we yawn (and why is it contagious)?
Why do we yawn, and why is it catching? It's not about oxygen, that's a myth. The leading ideas are brain cooling and shifting alertness, still unsettled.
The Science of Us
Why do we have belly buttons? The scar from your first lifeline
Why do we have belly buttons? Your navel is the scar left where the umbilical cord once fed you. Whether it is an innie or an outie is not the doctor's doing.
The Science of Us
Do twins have the same DNA? Not quite, and 5.2 is why
Do twins have the same DNA? Identical twins come close but never quite match. They differ by about 5.2 early mutations, and a lab can now tell them apart.
The Science of Us
Why does it rain? The journey of a single drop
Why does it rain? Water evaporates, rises, and cools into droplets around specks of dust, then they collide and grow until heavy enough to fall.
The Science of Us
Why do onions make you cry? A tiny acid attack on your eyes
Why do onions make you cry? Cutting one triggers a two-enzyme reaction releasing a gas that turns to mild sulfuric acid on your eyes. Plus the fix.
The Science of Us
Why Does Your Voice Sound Different on a Recording? You're Missing Your Skull
Why does your voice sound different on a recording? You hear it through your skull bones, which add deep tones. A recording catches only the air-borne version.
The Science of Us
Do identical twins have the same fingerprints? No, and here's why
Do identical twins have the same fingerprints? No. They share every gene but not the womb's fine print, so even a fingerprint scanner can tell them apart.
The Science of Us
Why does coffee make you poop? It isn't the caffeine
Why does coffee make you poop? Within minutes it triggers gut hormones and a colon reflex. And decaf does it too, so it isn't just the caffeine.
The Science of Us
Why do songs get stuck in your head?
Why do songs get stuck in your head? The science of earworms: the song features that trigger them, why they loop, and research-backed ways to make them stop.
The Science of Us
Cute aggression: why you want to squeeze the puppy
Cute aggression is the urge to squeeze or playfully bite adorable things. A Yale team named it in 2013; 2018 brain scans found the cause. Here's the science.
The Science of Us
Why Do You See Faces in Things? The Brain Trick That Never Turns Off
Why do we see faces in things like outlets and car grilles? It's your brain's face detector running hot, and the science goes deeper than you'd think.
The Science of Us
Why Can't You Tickle Yourself? Your Brain Is One Step Ahead
Why can't you tickle yourself? Your cerebellum predicts your own touch and cancels the sensation before it registers. Here's the weird science behind it.
The Science of Us
Why Do We Dream? What Science Actually Knows
Why do we dream? Science has several leading theories, from memory sorting to emotional processing to threat rehearsal. Here's what we really know about dreams.
The Science of Us
Why Is the Sky Blue? (And Why It Turns Red at Sunset)
Why is the sky blue? The real answer is a story about sunlight, tiny air molecules, and a trick of physics called Rayleigh scattering, explained simply.
How It Works
For the science hiding in plain sight.
How It Works
How do caves form? The slow magic of water and stone
How do caves form? Slightly acidic groundwater quietly dissolves limestone over thousands to millions of years, hollowing out rooms and growing stalactites.
How It Works
Why does popcorn pop? A tiny pressure cooker hits its limit
Why does popcorn pop? Each kernel is a sealed pressure cooker. Heat turns its water to steam, pressure climbs to about 9 atmospheres, and the hull bursts.
How It Works
How do airplanes fly? The wing pushes air down, the air pushes back
How do airplanes fly? A wing throws air downward and the air pushes the wing up. Here is the real physics of lift, the four forces, and the myth NASA debunks.
How It Works
Why is snow white when ice is clear?
Why is snow white when ice is clear? A snowbank scatters every color of light back at you in equal amounts, and that even mix is the white your eye reports.
How It Works
Why does salt melt ice? The chemistry behind the winter salt truck
Why does salt melt ice? Dissolved salt ions crowd out water molecules trying to rejoin the ice crystal, dropping the freezing point below 0 C so it melts.
How It Works
How do glow sticks work? A tiny, cold chemical fire
How do glow sticks work? Snapping one breaks a glass vial inside, mixing two chemicals that release their energy as light, not heat, like a firefly's cold glow.
How It Works
Why Does Pasta Water Boil Over? Blame the Starch
Why does pasta water boil over? Starch from the pasta turns the steam bubbles into a sticky foam that traps steam and climbs the pot until it spills.
How It Works
Why Does Your Tongue Stick to Cold Metal? Frozen Spit
Why does your tongue stick to cold metal? Metal pulls heat from your wet tongue so fast the saliva freezes into ice, gluing tongue to pole. Here's how to free it.
How It Works
Why Does Ice Crack When You Put It in Water? Thermal Shock
Why does ice crack when you put it in water? Thermal shock. The outer layer warms and expands while the cold core stays put, and brittle ice splits.
How It Works
How do magnets work? The quiet quantum trick inside iron
How do magnets work? Magnetism comes from moving electric charge and electron spin, lined up across regions of iron. The real, slightly strange answer.
How It Works
How does a compass work? It's chasing a moving target
How does a compass work? A magnetized needle lines up with Earth's magnetic field, pointing not to true north but to a magnetic pole that's drifting toward Siberia.
How It Works
How much does a cloud weigh? About a hundred elephants
How much does a cloud weigh? A small cumulus holds about 1.1 million pounds of water, the weight of 100 elephants, yet it floats. Here is the math and why.