Every What If? Lab

349 to explore · page 6 of 8

• Watch Try it What If? Lab What if the Sun stayed low in the sky? A low Sun spreads its light thinly over more ground, and in winter it is up for fewer hours too. In our sunlight model, London's noon Sun drops from about 62 degrees in June to about 15 degrees in December, and its daily sunlight falls to about one seventh.
• Watch Try it What If? Lab What if the Sun were heavier? The Sun's gravity bends Earth's path into a yearly loop. Make the Sun twice as heavy in our model and its pull gets stronger, so Earth must race around faster to stay on the same circle. The year shrinks from about 365 days to about 258.
• Watch What If? Lab What if the universe stopped expanding? Since the 1920s, astronomers have known that distant galaxies are moving apart as space stretches. In 1998 they found the stretching is speeding up, driven by something nobody understands, called dark energy. What if the expansion stopped? Our galaxy wouldn't notice, but the universe's long future would change, and scientists are still working out where it is heading.
• Watch Try it What If? Lab What if the water cycle changed? Warm air can hold more water vapor, about 7 percent more for each degree. In our model of the whole planet's water cycle, a world 2 °C warmer evaporates about 14 percent more water each year if rain kept up with that rule, or about 4 percent more at 2 percent per degree, a rate within the range climate models find.
• Watch Try it What If? Lab What if the whole Earth were covered by ocean? Water soaks up a lot of heat before it gets hot, and gives it back slowly. Turn a patch of damp ground into ocean in our model and watch the gap between day and night temperatures shrink, then see how the sea already keeps coastal towns mild.
• Watch Try it What If? Lab What if the wind blew twice as hard? A wind turbine turns moving air into electricity. In our model, a gentle 5 m/s wind lets a big turbine make about 0.15 megawatts. Double the wind to 10 m/s and it makes about 1.23 megawatts: eight times as much, because faster wind brings more air each second and each bit of air carries more energy.
• Watch What If? Lab What if the wind stopped blowing? Wind is air rushing from places of high pressure to places of low pressure. It carries heat, water and weather around the world, lifts seeds to new homes and has pushed sailing ships across oceans. Imagine all the air going still, and follow what might change.
• Watch What If? Lab What if the world ran on sunshine? Solar panels turn sunlight into electricity, and a 2020 World Bank study found that most countries get far more sunshine than they would need for all the electricity they use now. But the Sun sets every night, and winter days are short. Imagine a world running on sunshine and follow the big engineering puzzles: day and night, storing energy, and finding room for panels.
• Watch What If? Lab What if there were a planet between Mars and Jupiter? Between Mars and Jupiter lies the asteroid belt: millions of rocky leftovers that never built a planet. NASA explains that young Jupiter's gravity stopped them. Explore the belt, Jupiter's tug, the dwarf planet Ceres, and what kind of planet could have formed there.
• Watch Try it What If? Lab What if there were more greenhouse gases? Adding greenhouse gases makes it harder for Earth's heat to escape, so the planet warms until it balances again. In our model a small change in how freely heat escapes warms Earth by about 2.6 °C, and the oceans make the warming take years.
• Watch What If? Lab What if there were no acids? Acids are everywhere: in lemons and vinegar, in rain, and even in your stomach. Scientists measure how acidic something is with the pH scale. Imagine a world with no acids at all and follow the clues to see how much would change.
• Watch Try it What If? Lab What if there were no air resistance? Air pushes back on anything falling through it, and light, spread-out things like paper feel that push the most. Switch the air off in our model and a light paper cup drops as fast as a stone, landing in under a third of the time.
• Watch What If? Lab What if there were no clouds? Clouds shade the ground by day, send heat back down at night and are where rain comes from. Imagine a sky with no clouds at all, and follow what might happen to hot days, cold nights, rain and even the colors of the sky.
• Watch What If? Lab What if there were no decomposers? Bacteria, fungi, earthworms and millipedes break down dead leaves, wood and dead plants and animals, and give their nutrients back to the soil. National Geographic calls them Earth's cleanup crew. Imagine a world without them, and follow what might pile up, what might run short, and who does the work.
• Watch What If? Lab What if there were no echoes? An echo is sound that bounces back to you. Bats and dolphins send out sounds and listen for the echoes to find food, and ships use echoes to measure how deep the sea is. Imagine a world with no echoes and follow what might change for animals and people.
• Watch What If? Lab What if there were no electricity for a day? Electricity reaches your home through a giant network called the grid. Sometimes storms or faults cut it off for a while. Imagine a whole day without it: what happens to the lights and the fridge, how does the grid get electricity to you, and how do hospitals keep working when it stops?
• Watch Try it What If? Lab What if there were no friction? Friction is the grip between two surfaces. It slows a wooden block sliding down a ramp and stops it on the floor. Switch friction off in our model and the block races down faster and then slides along the floor forever.
• Watch What If? Lab What if there were no fungi? Fungi are a whole kingdom of living things, with about 144,000 known species, from tiny yeasts to big mushrooms. They puff up our bread, ripen some cheeses, rot dead wood and team up with plant roots. Imagine a world with no fungi at all and follow what might change.
• Watch What If? Lab What if there were no gears? A gear is a toothed wheel that turns another one. Gears can make things turn faster or slower, and trade speed for turning force. In this thought experiment, imagine bikes, clocks and machines with no gears, then see what the very first pedal bikes and old clocks tell us.
• Watch Try it What If? Lab What if there were no greenhouse gases? Greenhouse gases such as carbon dioxide and water vapor hold some of Earth's heat in, like a blanket. Take them all away in our energy-balance model and Earth's average temperature falls from about 15 °C to about −19 °C, well below freezing.
• Watch What If? Lab What if there were no magnets? You can see magnets holding pictures on a fridge, but most magnets are hidden. They sit inside electric motors, speakers and the generators that make electricity, and a compass needle is a magnet too. Imagine a world with no magnets and follow what might stop working.
• Watch What If? Lab What if there were no ocean currents? Ocean currents are like rivers in the sea. They carry warm water away from the equator and cold water away from the poles, and some lift food-rich water up from the deep. Imagine them stopping: follow the Gulf Stream, warm and cold coasts, and the rich fishing waters fed by upwelling.
• Watch What If? Lab What if there were no plastic? Plastic is light, cheap and lasts a long time, so it is everywhere: in toys, bottles, phones, cars and hospitals. Those same things make it hard to clean up when it ends up in the ocean. Imagine a world without plastic, then meet the older materials and the new plant-based plastics people are designing.
• Watch Try it What If? Lab What if there were no predators? In a meadow, rabbits have babies and foxes hunt them, so both numbers rise and fall in turns. Take every fox away in our model and watch what the rabbits do, then find out what happened in a real park when its wolves were taken away and brought back.
• Watch What If? Lab What if there were no satellites? Thousands of satellites quietly circle Earth every day. They watch the weather, help phones find where you are with GPS and carry TV signals and phone calls. Imagine a world without them, and discover how people found their way and forecast the weather before the first satellite launched in 1957.
• Watch What If? Lab What if there were no soil? Soil is broken-down rock mixed with rotted plants and animals, plus water, air and huge numbers of living things. It holds plant roots, feeds them and soaks up rain, and UNEP says about 95 percent of our food comes from it. Under good conditions, one inch of topsoil can take hundreds of years to form. Imagine a world with no soil, and follow what might change.
• Watch What If? Lab What if there were no spiders? Spiders around the world catch an estimated 400 to 800 million tons of prey every year, mostly insects. They also spin some of the toughest materials in nature. Imagine a world with no spiders: what would happen to all those insects, and what would we lose?
• Watch What If? Lab What if there were no springs? A spring stores energy when you squash or stretch it, then gives it back as it springs into shape. Imagine a world with no metal springs at all, and follow what would happen to bouncy beds, clicky pens, old-style clocks and car rides.
• Watch What If? Lab What if there were no wetlands? Marshes, swamps and bogs are wetlands: places where water covers the soil or sits just below it. EPA compares them to natural sponges that soak up rain and floodwater and let it go slowly. They also clean water and shelter many birds and young fish. Imagine a world with no wetlands, and follow what might change.
• Watch What If? Lab What if there were no wheels? A wheel turning on an axle makes heavy loads much easier to move. But people moved big things long before wheels, using sledges and rollers. In this thought experiment, see how they did it, when the first wheels appeared, and what a day without wheels might be like.
• Watch What If? Lab What if time slowed down when you moved fast? This what-if is real. Einstein's relativity says a moving clock ticks slightly slower, and scientists have measured it with atomic clocks, fast particles and GPS satellites. Explore how big the effect is, why we never notice it, and why your phone's map depends on correcting it.
• Watch What If? Lab What if trees never lost their leaves? Every autumn, maples, birches and many other trees drop their broad leaves, while pines and spruces stay green. Imagine broad-leaved trees keeping their leaves all winter: what would happen to their water, to their branches in a snowstorm, and to the bright autumn colors?
• Watch What If? Lab What if trees shared food underground? Almost every tree has a fungus partner living on its roots. The fungus brings water and minerals; the tree pays it in sugar. Some people say the fungi also link trees together so they can share food. Explore what scientists have measured, and why some of them say the 'sharing' story has gone further than the evidence.
• Watch What If? Lab What if tunnels could be dug anywhere? Tunnels carry trains, cars and water through mountains and under rivers. But digging one is hard: the ground can be solid rock or soft mud, and water is always trying to get in. Explore how tunnel builders hold back rock and water, and how giant boring machines dig and line a tunnel as they go.
• Watch Try it What If? Lab What if two pucks hit off-center? When a sliding puck hits an identical still puck straight on, it stops dead and the other one shoots away. Hit it off-center and both slide off, at a right angle to each other. Find out why, and why pool players know this trick.
• Watch What If? Lab What if Venus had Earth's air? Venus is about the same size as Earth, but its surface is hot enough to melt lead. Its thick carbon dioxide air traps heat in a runaway greenhouse effect, so Venus is even hotter than Mercury. Imagine swapping in Earth's air, and explore what a NASA climate model says about a cooler, cloudier Venus long ago.
• Watch What If? Lab What if volcanoes stopped erupting? Volcanoes build new land, like the island of Surtsey near Iceland, and their rock slowly breaks down into some of the richest soil on Earth. Over millions of years, gases from volcanoes even helped give Earth its air and oceans. Imagine every volcano going quiet, and follow what might change.
• Watch What If? Lab What if warmer seas changed ocean life? When seawater gets too warm, corals can lose the tiny algae that feed them and turn white. Fish and shellfish move toward cooler water, and a long ocean heatwave can leave whole food webs short of food. Explore what scientists have seen, and what they still study about storms.
• Watch Try it What If? Lab What if water were denser? Water pushes up on anything you put in it. A heavier, denser liquid pushes up harder. In our model, a block that sinks in water floats in a pretend liquid twice as dense, with only 60 percent of it under the surface.
• Watch Try it What If? Lab What if waves came from a faraway storm? Some waves are made by wind nearby: short, choppy and close together. Others are swells that have traveled thousands of kilometers from a distant storm: long, smooth and far apart. In our model, waves 1.5 meters high arriving every 14 seconds carry about 2.3 times the power of equally tall waves arriving every 6 seconds, and wear a sandy island away much faster.
• Watch What If? Lab What if waves had no wind? Most ocean waves are made by wind blowing over the water. So what if the wind stopped everywhere? New waves would stop forming, but swells from earlier storms could keep rolling in for a while. And the tide would still come in and go out, because tides are made by the pull of the Moon and the Sun, not by wind.
• Watch What If? Lab What if we built a space elevator? Rockets burn huge amounts of fuel to reach space. A space elevator would be a cable stretching from the equator about 35,786 kilometers up to a special orbit, with robot climbers riding up and down. NASA studies say it might cut the cost of reaching orbit hugely, but it needs a material far stronger than anything we can make in long lengths today. Explore the cable, the materials and the ride.
• Watch What If? Lab What if we could print a house? Giant 3D printers already build walls by squeezing out concrete one layer at a time, like icing from a piping bag. In 2026, a U.S. Army base in Texas opened the first of ten printed buildings for soldiers, and in 2022 a university in Maine printed a small house from wood fibers. What if we printed lots of our buildings? Explore how printed homes are made and whether they are really faster.
• Watch What If? Lab What if we could see the far side of the Moon? The Moon spins once for every trip around Earth, so the same face always points at us. The far side isn't dark: it gets sunlight too. It has been seen only by spacecraft and astronauts, and it looks very different, crowded with craters. Find out why one face points at us, what the far side holds and how a rover explored it.
• Watch What If? Lab What if we could see the wind? Wind is moving air, and air is invisible. So people watch what the wind moves: smoke, leaves, flags, clouds and kites. Scientists even make wind maps from satellite pictures. Imagine the wind suddenly becoming visible, and follow the swirls, maps and kites that might appear.
• Watch What If? Lab What if we could travel at the speed of light? Light travels about 300,000 kilometers every second. At that speed you could reach the Moon in 1.3 seconds, but the nearest star after the Sun would still take more than four years. And physics says nothing with mass can ever quite reach light speed. Explore why.
• Watch What If? Lab What if we could understand animal sounds? Animals pass messages with sounds, smells, movements and touch. Scientists have already worked out what a honey bee's dance means, and they are listening hard to whales. Imagine understanding three animals, a bee, a whale and a dog, and find out how much we really know.
• Watch What If? Lab What if we found life on another world? So far, the only life we know of is here on Earth. Scientists search for signs of life with rovers on Mars, spacecraft heading to icy moons and powerful telescopes. Find out how they look, why they test every clue so carefully, and imagine what a first discovery might be like.