Every What If? Lab

349 to explore · page 7 of 8

• Watch What If? Lab What if we sent a message to the stars? Radio messages travel at the speed of light, about 300,000 kilometers every second. Even so, a hello to the nearest star beyond the Sun would take more than four years to arrive. Explore the real messages people have sent, from Voyager's golden records to the 1974 Arecibo message, and decide what you would say.
• Watch What If? Lab What if we used heat from inside Earth? The deeper you go underground, the hotter the rocks and water get. In Iceland, hot water from underground heats most homes, and in Kenya, underground steam makes more than 40 percent of the country's electricity. Explore what would happen if we used Earth's own heat: in volcanic places like Iceland, at hot springs, and even just a few feet under your own backyard.
• Watch What If? Lab What if weather forecasts were always right? NOAA said in 2025 that a five-day weather forecast is right about 90 percent of the time, but a ten-day forecast is right only about half the time. Why? Because tiny changes in the air can grow into big differences, an idea called the butterfly effect. Imagine forecasts that were never wrong, and discover the satellites, balloons and supercomputers that make today's forecasts so good.
• Watch What If? Lab What if whales returned to every ocean? Hunting in the last century took away most of the world's great whales, and since a 1985 ban on commercial whaling many are growing in number again. Whale poop feeds the tiny drifting plants at the base of the ocean food web, and whale bodies carry carbon to the deep sea. Imagine whales back in every ocean and follow what they might do.
• Watch Try it What If? Lab What if wheels were square? A square wheel on a flat road lifts its axle up and down with every corner. In our model it bounces almost 9 centimeters and loses most of its motion at each bump. On a road of curved humps, though, the same square rolls perfectly smoothly.
• Watch Try it What If? Lab What if windows were made of diamond? Light bends when it passes from air into a window. Swap the glass for diamond in our model and the same beam bends far more, and much more of it bounces back. That strong bending is part of why a cut diamond sparkles.
• Watch Try it What If? Lab What if winter were much colder? Heat leaks out of a house faster when it is colder outside. In our model, an insulated house kept at 20 °C needs about 86 kilowatt-hours of heat a day when it is 0 °C outside. Drop the outside to −20 °C and the gap doubles, so it needs twice as much: about 173 kilowatt-hours.
• Watch Try it What If? Lab What if wolves returned to a park? For nearly 70 years, Yellowstone National Park had no wolf packs. In 1995, people brought wolves back. Start with a model park that has no wolves, put the wolves back into its food web, and see what changes for the elk, the willows and the animals that need them. Then find out what scientists in the real park are still working out.
• Watch Try it What If? Lab What if you added more bulbs in a row? One bulb on a 3-volt battery glows brightly. Add more bulbs in a row, all on one path, and each new bulb adds resistance, so less current flows. In our model, four bulbs in a row each glow at only 6 percent of one bulb's brightness. Find out why, and how real strings of lights use this idea.
• Watch Try it What If? Lab What if you boiled water on a high mountain? Water does not always boil at 100 °C. Climb a mountain and the air pressure drops, so water boils at a lower temperature. In our model of the atmosphere, water 5 kilometers up boils at about 83 °C, which is why food cooked in boiling water takes longer high up.
• Watch Try it What If? Lab What if you climbed Mount Everest? The higher you go, the thinner the air gets. In this lab, travel from sea level to 8.8 kilometers, near the top of Mount Everest, using a model of the atmosphere. Watch the air pressure fall to about a third, the temperature drop far below freezing, and water boil at under 70 °C.
• Watch What If? Lab What if you could dive to the deepest trench? The Challenger Deep, at the bottom of the Mariana Trench, is about 11 kilometers down: deeper than Mount Everest is tall. Imagine diving there. Discover how strong the water's squeeze becomes, what lives in the dark, and the explorers who have already made the trip.
• Watch What If? Lab What if you could hear like a bat? People hear sounds from about 20 to 20,000 vibrations a second. Bats can hear sounds up to about 100,000. They shout out high calls and listen for the echoes to find insects in the dark: that's echolocation. Imagine bat ears, and discover the hidden world of sound all around you.
• Watch Try it What If? Lab What if you could lift a car with a lever? A lever is a bar that turns on a pivot called a fulcrum. In this lab, a 1,000-kilogram load sits on a lever. Move the fulcrum close to the load, make your side long, and see how small your push becomes, and how far your end has to move.
• Watch What If? Lab What if you could not sweat? Sweat is your body's built-in cooler. When it dries off your skin, it carries heat away with it. Dogs can hardly sweat, so they pant instead. Imagine a body with no sweat, and discover the clever ways people and animals keep cool.
• Watch What If? Lab What if you could regrow a hand? Axolotls, salamanders from Mexico, can regrow whole legs, and even parts of their hearts and brains. Our bodies can heal too: skin grows back over a scrape and broken bones knit together. But we can't regrow a hand. Discover how axolotls do it, what our own bodies can regrow, and what scientists are learning.
• Watch What If? Lab What if you could remember everything? Imagine never forgetting anything: every lunch, every conversation, every page you ever read. A few people come close, remembering what they did on almost any date. But scientists think forgetting is useful too. Explore how memories form, why your brain lets some things fade, and tricks that help you remember what matters.
• Watch What If? Lab What if you could ride a comet? A comet's center is a dusty ball of ice a few kilometers across, racing around the Sun. In 2014, the European Space Agency's Philae lander touched down on comet 67P, and because the comet's gravity is so weak, it bounced! Imagine riding a comet, then see what a real spacecraft found.
• Watch What If? Lab What if you could run at the speed of sound? Sound zips through air at about 343 meters per second, more than 30 times faster than the fastest human sprint. Anything that goes faster than sound pushes the air into a shock wave that people hear as a sonic boom. Imagine running that fast, then meet the jets that really do it.
• Watch What If? Lab What if you could see Earth from the Moon? From the Moon, Earth hangs in a pitch-black sky, glowing with blue oceans and white clouds. Like the Moon, it goes through phases: when we see a crescent Moon, Earth looks nearly full from the Moon. Discover Apollo 8's famous Earthrise, Earth's phases and the photos astronauts took of our blue planet.
• Watch What If? Lab What if you could see in the dark? Your eyes need light to see. Cats need only about a sixth as much light as people, thanks to a shiny mirror layer at the back of their eyes. And special cameras can 'see' infrared light, the invisible glow of warm bodies. Imagine having night vision and find out how it really works.
• Watch What If? Lab What if you could see like an eagle? Some eagles can see about twice as much fine detail as people can. Their big eyes are packed with light-sensing cells, and many birds of prey have two extra-sharp spots in each eye where we have one. Imagine trading eyes with an eagle and find out what you would gain, and what eagles might not see at all.
• Watch What If? Lab What if you could see sound? Sound is a wave of squeezed and stretched air that our ears can feel but our eyes can't see. Imagine seeing it, then meet the real tools, like spectrograms and special cameras, that scientists use to turn sound and moving air into pictures.
• Watch What If? Lab What if you could see stars in the daytime? The stars don't go anywhere during the day. Sunlight scattered by our air makes the whole sky bright blue, and that glow hides the much fainter stars. Explore three ways the stars can show up in daytime: on the Moon, during a total solar eclipse, and in what happens to our sky.
• Watch What If? Lab What if you could shrink to the size of an ant? Small creatures live in a strange world. For a tiny ant, the air keeps a fall slow, a drop of water might look as big as a beach ball, and its neck turns out to be very strong for its size. Imagine shrinking to ant size and explore each of these, one careful step at a time.
• Watch Try it What If? Lab What if you could stand on Saturn? You could not really stand on Saturn: it is a ball of gas and liquid with no solid surface. But imagine floating at its cloud tops. Saturn has 95 times Earth's mass, yet in our model you would weigh only about 14 percent more than at home, because Saturn is so wide that its cloud tops are very far from its center.
• Watch Try it What If? Lab What if you could stand where airliners fly? Air gets colder and thinner the higher you go. In our model of the standard atmosphere, climbing from sea level to 11 kilometers, near where airliners cruise, cools the air from 15 °C to about −56 °C and leaves less than a quarter of the air pressure.
• Watch What If? Lab What if you could walk on Jupiter’s cloud tops? Jupiter is so big that about 1,000 Earths could fit inside it, but it has no solid ground at all. Imagine standing on a platform at its cloud tops: you would feel more than twice as heavy, and you could watch a storm twice as wide as Earth.
• Watch Try it What If? Lab What if you counted the seconds after lightning? You see lightning almost at once, but its thunder travels at the speed of sound, about 343 meters per second. The National Weather Service says thunder takes about 5 seconds to travel a mile, so counting the seconds tells you how far away the lightning was. In our model, thunder from 1,700 meters away arrives after about 5 seconds.
• Watch Try it What If? Lab What if you dropped a ball from four times higher? A ball dropped from 10 meters lands in about 1.4 seconds. Drop it from 40 meters, four times as high, and you might expect four times as long. In our model it takes only about 2.9 seconds: just twice as long, because a falling ball keeps speeding up.
• Watch What If? Lab What if you found a meteorite? Meteorites are pieces of space rock that survived a fiery trip through Earth's air. Most come from asteroids, a few from the Moon or Mars, and many are older than any rock ever found on Earth. Imagine finding one: learn the clues scientists look for, what is inside, and why the right first step is to tell a grown-up and ask a museum or university.
• Watch What If? Lab What if you had gills? Fish don't breathe water itself: their gills take tiny amounts of oxygen gas out of the water. Air is about one fifth oxygen, but water holds only a few oxygen molecules in every million. Imagine growing gills, and find out how fish, and the smiling axolotl, get enough oxygen.
• Watch What If? Lab What if you had no bones? An adult has 206 bones. They hold the body up, guard the brain, heart and lungs, and give muscles something to pull on. Imagine a body with no bones, then meet animals like the octopus that really do live without them.
• Watch What If? Lab What if you had no sense of balance? Deep inside each ear are tiny loops filled with fluid. They tell your brain when your head turns and tilts, and together with your eyes and the touch sensors in your legs, they keep you steady. Imagine losing that sense, then discover why spinning makes you dizzy and how astronauts relearn their balance back on Earth.
• Watch What If? Lab What if you had no sense of smell? Your nose does more than you think. Much of what you call taste is really smell, and smell can warn you about smoke or food that has gone bad. Imagine a day with no sense of smell, then meet a dog, whose nose has up to 300 million smell receptors.
• Watch What If? Lab What if you had no teeth? Your teeth cut, tear and grind food into small pieces so you can swallow it. Imagine eating with no teeth at all! Find out what each kind of tooth does, how baby teeth make way for adult teeth, and how birds manage without any teeth, using a muscly stomach called a gizzard.
• Watch What If? Lab What if you had no thumbs? Your thumb is special: it can swing across your hand and touch the tip of every finger. That move lets you pinch, grip, write and use tools. Imagine a day without thumbs, then meet chimpanzees that grip with thumbs like ours and giant pandas that grasp bamboo with a clever 'pseudo thumb.'
• Watch Try it What If? Lab What if you jumped on the Moon? The Moon's gravity is only about one sixth as strong as Earth's. In our model, a jump that lifts a child about 29 centimeters on Earth carries them about 1.8 meters on the Moon, and they stay in the air for about 3 seconds instead of half a second.
• Watch Try it What If? Lab What if you kept adding bulbs side by side? When bulbs are wired side by side, each one has its own path to the battery. Add a second, third and fourth bulb, and in our model each one keeps glowing as brightly as the first. But the battery has to push out more and more current to keep them all lit, and that has a cost.
• Watch What If? Lab What if you lived on a space station? On the International Space Station, astronauts and everything around them float. That sounds fun, but without the steady pull of gravity to work against, bones and muscles get weaker. That's why astronauts exercise for about two hours every day. Imagine moving in, and find out how they stay strong.
• Watch Try it What If? Lab What if you lived on Mars? You would be made of exactly the same amount of stuff on Mars, but Mars pulls on you less than Earth does. In our model, a bathroom scale there would show only a little over a third of your Earth reading, and your jumps would go more than twice as high.
• Watch Try it What If? Lab What if you lived on the equator? On the equator the Sun is up for about 12 hours every single day of the year, and it always climbs high at noon. In our sunlight model, moving from London to the equator on December 21 turns a 7.6-hour winter day into a 12-hour day. Near the equator, seasons are mostly about rain, not cold.
• Watch Try it What If? Lab What if you lived where the Sun never sets? North of the Arctic Circle, Earth's tilt keeps the Sun above the horizon all day and all night around midsummer: the midnight Sun. In our sunlight model, moving from 40° north to 69.5° north on June 21 turns a 14.8-hour day into 24 hours of daylight.
• Watch What If? Lab What if you never blinked? You blink about 15 times a minute, mostly without noticing. Each blink spreads a thin layer of tears across your eyes to keep them moist and wash away dust. Imagine never blinking again, then discover what tears do, why eyes feel dry, and how fish and snakes manage with no eyelids that close.
• Watch What If? Lab What if you never got hiccups? A hiccup is a sudden twitch of your diaphragm, the dome-shaped muscle under your lungs that helps you breathe. Then your vocal cords snap shut and make the 'hic' sound. Imagine never hiccuping again, and discover what scientists have found out about hiccups, from babies before they are born to the tricks people try.
• Watch What If? Lab What if you never slept? You spend about a third of your life asleep. While you sleep, your brain is busy sorting the day's memories and, scientists think, tidying itself up. Imagine never sleeping, then meet birds and dolphins that can rest one half of the brain at a time.
• Watch What If? Lab What if you played catch on a merry-go-round? Roll a ball straight across a spinning merry-go-round and, to the riders, it seems to curve away. Someone standing on the ground sees it go straight. The same trick, on our spinning Earth, bends winds and makes big storms swirl.
• Watch Try it What If? Lab What if you threw a ball at a lower angle? Throw a ball at 15 meters per second, aimed halfway between flat and straight up (45°), and in our model it lands about 23 meters away. Aim much flatter, at 15°, and it lands only about 11 meters away, in less than a second. Without air, 45° sends a ball farthest on flat ground.