Every What If? Lab

349 to explore · page 4 of 8

• Watch What If? Lab What if forests became grasslands? Forests and grasslands are next-door neighbors in many places, and fire, grazing animals and rain decide where one ends and the other begins. Imagine a forest becoming a grassland: who would move in, what would happen to the soil, and where would all the carbon in the trees go?
• Watch Try it What If? Lab What if foxes became better hunters? In a meadow model, rabbits and foxes rise and fall in turns. Make every fox twice as good at catching rabbits and you might expect a meadow full of well-fed foxes. The model says the opposite: in the long run there are fewer foxes, not more. Find out why, and how real predators and prey compare.
• Watch What If? Lab What if germs did not exist? We often think of germs as bad, but many of the tiny living things around us are harmless or even helpful. About as many microbes live in your body as you have body cells, and they help you digest food and help your immune system develop, and helpful bacteria turn milk into yogurt and cheese. Imagine a world with no microbes at all, and see what we would lose.
• Watch Try it What If? Lab What if glaciers melted? Glaciers are huge, slow-moving masses of ice on land. When land ice melts, its water runs into the ocean and raises the sea. In our model, melting every mountain glacier on Earth would lift the sea by about 40 centimeters; scientists' best estimate is a little less, about 32.
• Watch What If? Lab What if glass were bendy? Glass is made by melting sand and cooling it quickly. When it's cool, it's hard and brittle, so it cracks instead of bending. But hot glass is soft, and glass thinner than paper can bend. Imagine glass that was bendy and follow what might change.
• Watch What If? Lab What if glue stuck to everything? Glue and tape stick by spreading into tiny bumps on a surface and holding on with weak pulls between molecules. They stick well to some things and badly to others. Imagine a glue that stuck to everything, and follow the clues: how glue holds on, sticky notes and gecko feet.
• Watch What If? Lab What if gold were as common as sand? Gold makes up only a few parts in every billion of Earth's crust, while silicon, the main element in sand, makes up more than a quarter. Gold never rusts, so tiny amounts of it help our phones work. Imagine gold as common as sand and follow what might change.
• Watch Try it What If? Lab What if gravity disappeared? Gravity is the pull that makes a dropped ball fall and keeps your feet on the ground. Switch it off in our model and watch what a ball does instead, then find out why astronauts float.
• Watch Try it What If? Lab What if gravity doubled? Gravity makes a dropped ball speed up as it falls. Make the pull twice as strong in our model and the ball speeds up twice as fast, so it lands sooner and hits the ground harder. But it does not land in half the time. Find out why.
• Watch What If? Lab What if gravity pulled sideways? “Down” is simply the direction gravity pulls: toward the center of Earth. Imagine gravity pulling sideways instead, and follow what would happen to walking, to rivers, and to the very meaning of up and down.
• Watch What If? Lab What if heat flowed from cold to hot? Drop an ice cube into hot tea and the tea cools while the ice melts: heat moves from hot to cold, all by itself. It never flows the other way on its own. Fridges and heat pumps can move heat from cold to hot, but only by using energy. Imagine a world where heat flowed backward.
• Watch What If? Lab What if honeybees could not dance? When a honeybee finds great flowers, she flies home and dances on the honeycomb. The dance tells other bees which way to fly and how far. Scientists have even tested hives where the dance can't point the way. Imagine bees that could not dance and follow what might change.
• Watch What If? Lab What if humans had tails? Many animals use their tails to balance, to signal to each other, or even to grab branches. People and apes have no tails, but we each have a small tailbone at the bottom of our spine. Imagine life with a tail, meet monkeys that hang by theirs, and discover what scientists learned in 2024 about how our ancestors lost their tails.
• Watch What If? Lab What if hurricanes could be steered? Hurricanes are huge spinning storms that grow over warm ocean water. Nobody can steer or stop one today: a hurricane holds far more energy than people could ever push around. What people can do is forecast where it may go and get ready early. Imagine steering one, then see why forecasts are the real answer.
• Watch What If? Lab What if ice cream never melted? Ice cream is a frozen foam of tiny ice crystals, air bubbles and fat, held together by a sugary syrup that never quite freezes. Imagine ice cream that never melted, and follow the clues: melting, fat and air bubbles, and how ice cream is kept cold on its way to you.
• Watch Try it What If? Lab What if ice were heavier than water? Ice floats because it is about 9 percent less dense than liquid water, which is unusual: most solids sink in their own liquid. Make a block of pretend ice heavier than water in our model, watch it sink, and find out why floating ice matters for life in lakes.
• Watch Try it What If? Lab What if icebergs were made of wood? An iceberg floats with about nine-tenths of it hidden under the water. Swap the ice for wood in our model and watch the block bob up much higher, then find out why how much shows depends on density.
• Watch Try it What If? Lab What if insects vanished? Insects eat plants, and birds, mice and bears eat insects. In our forest food web, take the insects out and see who could go hungry and who could change. Then find out why scientists are counting insects carefully, and how people help them.
• Watch What If? Lab What if it rained every day? Rain is wonderful: it waters plants and fills rivers. But what if it rained every day? Soil can only soak up so much, so more water would run into rivers. Some rainforests and mountain slopes get rain very often, and life there is built for it. Explore what daily rain would change.
• Watch Try it What If? Lab What if June were winter? Earth's two halves take turns leaning toward the Sun, so they have opposite seasons. In our sunlight model, on June 21 London gets 16.4 hours of daylight and a high Sun, while Sydney, south of the equator, gets just 9.7 hours and a low Sun: its shortest day of the year.
• Watch What If? Lab What if light had only one color? White sunlight is secretly a mixture of every color, from red to violet. Raindrops and glass prisms spread it out into a rainbow. Imagine light that had only one color: there might be no rainbows, and the world might look like one color in different shades.
• Watch Try it What If? Lab What if light reflected differently? Light leaving water bends as it crosses into air, and a little of it bounces back. Tilt the beam past about 49 degrees and something remarkable happens: no light gets out at all. Every bit reflects back inside, the trick that keeps light inside optical fibers.
• Watch What If? Lab What if light traveled as slowly as a bicycle? Light zips along at almost 300,000 kilometers every second, so fast that seeing seems instant. But it isn't: you always see things slightly in the past. In 1999, scientists slowed light to about 17 meters per second, the speed of a sprinting cyclist. Imagine a world where light always moved that slowly.
• Watch What If? Lab What if lightning never struck? Lightning is a giant electric spark from a storm cloud. It's powerful, but it also does useful jobs: it turns some nitrogen in the air into plant food, and its fires help some forests renew. Imagine a world where lightning never struck, and see what would change and what would carry on.
• Watch Try it What If? Lab What if magnets became stronger? A magnet's pull fades very fast as you move away. In our model, a ceramic magnet can't budge a paperclip 5 centimeters away, but a magnet three times stronger pulls it right in. Yet its reach grows by much less than its strength.
• Watch What If? Lab What if mangroves lined every tropical coast? Mangroves are trees that grow where land meets the sea in warm places, standing on tangled roots. Their roots calm waves, give young fish a safe place to grow, and hold lots of carbon in the mud. Imagine mangroves along every tropical coast and follow three paths: calmer waves, fish nurseries and stored carbon, then find out where mangroves can and can't grow.
• Watch What If? Lab What if Mars had oceans again? Mars is a cold, dusty desert today, but rovers have found dry riverbeds, deltas and an ancient lake. Its air is now so thin that liquid water can't last on the surface. Imagine a blue Mars, find out what it would need, and see a possible clue to past life that NASA's Perseverance rover has found.
• Watch What If? Lab What if metal melted in your hand? Every metal melts at its own temperature. Iron needs more than 1,500 °C, but a metal called gallium melts at just under 30 °C, cooler than your body. Imagine if all metals melted that easily and follow what might change.
• Watch What If? Lab What if metal never rusted? Rust forms when iron and steel react with oxygen and water. It slowly eats away bikes, gates and even giant bridges, so people fight it with paint, zinc and special steels. Imagine a world where metal never rusted and follow what might change.
• Watch What If? Lab What if meteor showers happened every night? A few shooting stars streak across any clear night sky, but during a meteor shower you might see dozens an hour. Showers happen when Earth passes through dust left by a comet, which is why they come back on the same dates every year. Imagine a shower every night, and find out what that would take.
• Watch What If? Lab What if migratory animals couldn’t reach their destinations? Every year, birds, butterflies, deer and pronghorn travel huge distances between their summer and winter homes. Along the way they need stopover places to eat and rest, and clear paths across the land. Imagine those stops disappearing or those paths blocked by roads and fences, then meet the wildlife bridges and protected places that help animals travel.
• Watch What If? Lab What if milk never turned into cheese? Cheese starts as milk. Helpful bacteria turn milk sugar into acid, and an enzyme called rennet makes milk proteins clump into curds, leaving a watery liquid called whey. Imagine milk that never turned into cheese, and follow the clues: bacteria and enzymes, curds and whey, and yogurt.
• Watch What If? Lab What if mirrors did not exist? A mirror is a very smooth, shiny surface that bounces light back neatly, so it makes a clear picture of you. Mirrors also gather starlight in giant telescopes and help people see around corners with periscopes. Imagine a world with no mirrors and follow what might change.
• Watch What If? Lab What if mosquitoes disappeared? Nobody enjoys an itchy mosquito bite. But mosquitoes are also food for fish, dragonflies, birds and bats, and some even pollinate flowers. Some kinds can also carry germs that make people sick. Imagine every mosquito gone: what would we gain, what might we lose, and why aren't scientists sure?
• Watch What If? Lab What if nothing could bounce? A ball bounces because it squashes when it hits the ground and then springs back, giving back the energy it stored. Springs store energy in the same way, and sound bounces off walls as echoes. Imagine a world where nothing could spring back, and follow what might change for games, sounds and springs.
• Watch Try it What If? Lab What if objects had different masses? When two equal pucks hit head-on, the first one stops and the second one zooms away. Make the second puck ten times heavier and everything changes: the light puck bounces back and the heavy one only creeps forward.
• Watch What If? Lab What if oil and water mixed? Oil and water won't stay mixed because water molecules cling to each other much more strongly than they cling to oil. But helpers like egg yolk and soap can hold tiny oil drops in water. Imagine oil and water that mixed easily and follow what might change.
• Watch Try it What If? Lab What if one bulb in a string broke? In a series circuit, electric current has only one path, so it must flow through every bulb in turn. Take one bulb out of our model and the path is broken: all three bulbs go dark. Then wire the same bulbs side by side and see what changes.
• Watch Try it What If? Lab What if orcas left the Southern Ocean? Orcas are apex predators: they eat at the top of the food web. Take them out of our model's Southern Ocean food web and the seals, penguins and fish they eat could become more common, which then changes the food of others. Explore the knock-on effects, and the real orcas that make long trips north.
• Watch What If? Lab What if our galaxy met another galaxy? The Andromeda galaxy is heading toward our Milky Way. Astronomers once expected a head-on meeting in about 4 billion years. A 2025 study called it a 50-50 chance in the next 10 billion years; a 2026 study says about 90 percent. Nobody is certain yet. If they meet, stars are so far apart that they would almost never bump, but the galaxies could blend into one new shape.
• Watch What If? Lab What if our Sun were a different color? A star's color tells you how hot it is: red stars are the coolest and blue stars the hottest. Our Sun is actually white, though it looks yellow through our air. NASA scientists have even worked out that plants on planets around other stars might not be green.
• Watch What If? Lab What if paper were waterproof? Paper is a mat of tiny plant fibers that water loves to cling to. Water creeps into the spaces between them and loosens the bonds that hold them together, so wet paper goes soft. Coatings can keep water out. Imagine paper that was always waterproof and follow what might change.
• Watch What If? Lab What if pencil lead were diamond? The gray core of a pencil is graphite, a form of carbon. A diamond is carbon too. The difference is how the carbon atoms hold on to each other: in sheets that slide in graphite, in a tight 3D net in diamond. Imagine a pencil with a diamond core and follow what might change.
• Watch What If? Lab What if penguins could fly? Penguins are birds whose wings became stiff flippers for swimming. Their ancestors flew, but today's penguins are superb divers instead. Imagine a penguin that could fly: what would it need to change, and what might it lose underwater?
• Watch What If? Lab What if people built homes on Mars? Mars has air you cannot breathe, temperatures far below freezing and no magnetic shield like Earth's. A home there would need sealed rooms, a way to make oxygen and water, and gardens for fresh food. NASA is already testing pieces of the puzzle, from an oxygen maker on Mars to a 3D-printed practice habitat in Texas.
• Watch What If? Lab What if planets were not round? Big worlds are round because gravity pulls everything toward the center from all sides. Small asteroids don't have enough gravity to do that, so most stay lumpy. Imagine a cube-shaped planet, meet the lumpy asteroids, and compare worlds to see how big something must be before gravity rounds it off.
• Watch What If? Lab What if plants ate insects everywhere? Carnivorous plants catch insects to get nutrients their soggy, poor soil can't give them. They still make food from sunlight. Imagine if every plant everywhere caught insects: would it help them, and why do so few plants bother?
• Watch What If? Lab What if plants could walk? A plant can't get up and walk to a sunnier spot or a new home. Instead, its seeds travel by wind, water and animals, its roots hold it firmly in the ground, and its stems and leaves slowly turn and bend. Imagine a walking plant: what would it gain, and what would it give up?