Topic
Weather questions for kids
Here are 322 questions about weather from 23 A Million Whys books, each with a short video answer. Book 7, The Weather Expedition is all about weather, and the rest come from other books in the series. Tap any question to watch the video and read the answer.
From Book 7: The Weather Expedition (150)
Why Do Clouds Form in the Sky?
A cloud is not a puffy pillow. It is billions of tiny water droplets floating together.
Why Are Some Clouds Fluffy and Some Flat?
Clouds come in lots of shapes, and the shape is a clue about the air around them. Fluffy clouds are called cumulus and form where warm air rises in bubbles.
Why Do Clouds Look White?
Sunlight looks white, but it is really a mix of every color of the rainbow. A cloud is full of tiny water droplets that bounce sunlight in every direction.
Why Do Storm Clouds Look Gray or Black?
Storm clouds look dark because they are thick, tall, and packed with water droplets and ice. That much material blocks and scatters sunlight, so very little light gets through to the bottom of the cloud.
Why Does Fog Hug the Ground?
Fog is simply a cloud that touches the ground. It forms when the air near the ground cools enough for invisible water vapor to turn into tiny droplets.
Why Is Fog Thicker in the Morning?
Fog is often thickest around sunrise, after the coldest part of the night. All night long the ground gives off heat and cools the air near it.
Why Does Dew Sparkle on Grass?
Dew is made of tiny beads of water that appear on grass overnight. At night the grass cools down, and invisible water vapor in the air touches it and turns into liquid droplets.
Why Does Rain Fall as Drops, Not One Big Splash?
Inside a cloud there are millions of tiny droplets that are too light to fall. They bump into each other and join up, growing bigger and bigger.
Why Do Raindrops Look Like Teardrops in Cartoons?
In cartoons, raindrops have a pointy top and a round bottom, like a teardrop. But real falling raindrops are shaped more like rounded hamburger buns.
Why Does Drizzle Feel Different From a Downpour?
Drizzle and downpours are both rain, but the drops are very different sizes. Drizzle drops are tiny and light, so they float down gently.
Why Does Rain Smell So Good After a Dry Spell?
That fresh smell after rain is called petrichor. It comes from oils made by plants and tiny living things in the soil.
Why Do Puddles Form and Then Disappear?
A puddle forms where rain collects faster than the ground can soak it up. Then it disappears in two ways: some water seeps down into the soil, and some evaporates into the air as invisible vapor.
Why Does Water Drip From Leaves After Rain?
Leaves catch rain like tiny umbrellas, and they hold on to a lot of water. After the rain stops, the stored water slowly slides off in drips.
Why Can You See Your Breath on a Cold Day?
Your breath is warm and full of invisible water vapor from inside your body. On a cold day, that warm air meets chilly air right outside your mouth.
Why Does Steam Rise From a Hot Sidewalk After Rain?
When rain falls on hot pavement, the water can start to rise again right away. The sidewalk is much warmer than the rain, so the leftover water heats up quickly.
Why Do Mountains Make Their Own Clouds?
Mountains can build clouds all on their own. When wind meets a mountain, the air has nowhere to go but up.
Why Is There Fog Near Lakes and Rivers?
Lakes and rivers keep adding invisible water vapor to the air above them. When cool night air settles over that moist air, the vapor can turn into tiny droplets.
Why Do Some Days Feel Sticky Before It Rains?
Before many storms, the air is full of water vapor, so the humidity is high. When the air is that damp, your sweat has a hard time drying off.
Why Does Hail Fall as Icy Balls?
Hail is a ball of ice that forms inside a thunderstorm. Strong winds that blow upward, called updrafts, toss raindrops high into freezing air.
Why Does Sleet Bounce and Snow Float?
Sleet and snow both fall in cold weather, but they feel very different. Sleet is made of small, hard pellets of ice, so it bounces.
Why Does Frost Paint Windows?
On very cold mornings, windows can wake up covered in ferny, feathery patterns. That is frost, and it is made by invisible water vapor in the air.
Why Do Clouds Sometimes Look Like Animals?
When you see a cloud shaped like a dragon, your brain is doing something clever. Brains love finding faces and animals in random shapes.
Why Can Airplanes Fly Through Clouds?
A cloud looks like a solid pillow, but it is not solid at all. It is mostly air, with tiny droplets spaced far apart.
Why Do Weather Balloons Go So High?
Weather balloons carry little sensors called radiosondes up into the sky. They rise far above the clouds, into thin air, to measure temperature, humidity, and wind.
Why Do Scientists Name Cloud Types in Latin?
Scientists around the world study clouds, but they speak many different languages. So they use Latin names, like cumulus, stratus, and cirrus, that anyone can share.
Why Do Thunderstorms Build So Fast?
On a hot, humid afternoon, a calm blue sky can turn into a thunderstorm in less than an hour. Hot, moist air rockets upward, and it cools as it rises.
Why Does Thunder Rumble After Lightning?
Lightning and thunder happen at exactly the same moment. But you see the flash first and hear the boom later.
Why Is Lightning So Bright?
A flash of lightning can light up the whole sky, even in the middle of the night. That is because the lightning channel gets incredibly hot, hotter than the surface of the Sun.
Why Does Lightning Zigzag?
Lightning never travels in a straight line. It zigzags and branches across the sky.
Why Do We Count Seconds After a Flash?
Counting the seconds between a flash of lightning and the boom of thunder tells you how far away the storm is. That helps you know if the storm is coming closer or moving away.
Why Is Metal Not a Lightning Magnet the Way Myths Say?
Many people believe metal pulls lightning toward it like a magnet, but that is a myth. Metal does not attract lightning.
Why Do Tall Trees and Towers Get Struck More Often?
Lightning often hits the tallest handy point. Tall trees and towers stick up into the part of the sky where the storm's electricity is.
Why Is a Car Usually Safer in a Storm (But Not Always)?
A hard-topped car with its windows up can protect you from lightning, but only sometimes. If lightning strikes it, the metal shell helps carry the electricity around the outside.
Why Should You Avoid Open Fields in Lightning?
An open field has no tall buildings or trees, so a person standing in it becomes one of the tallest things around. That makes you a risky target for lightning.
Why Does Thunder Shake Windows?
Thunder is a sound, and sound is a wave that pushes on the air. A loud, close thunderclap pushes hard enough to make windows rattle.
Why Do Some Storms Make Hail the Size of Marbles?
Some thunderstorms make hail as big as marbles, or even bigger. That happens when the storm has very strong updrafts that keep ice floating high up for longer.
Why Do Tornadoes Spin?
A tornado is a spinning column of air that reaches from a storm cloud to the ground. It starts with winds that blow in different directions at different heights.
Why Is a Tornado Watch Different From a Warning?
A tornado watch and a tornado warning sound alike, but they mean very different things. A watch means a tornado could happen, so be ready.
Why Do Hurricanes Have an “Eye”?
A hurricane is a giant spinning storm made of clouds, wind, and rain. In the very middle, there is a calm spot called the eye.
Why Do Hurricanes Need Warm Ocean Water?
A hurricane is like an engine, and warm ocean water is its fuel. The sea has to be about 26 degrees Celsius, or 80 degrees Fahrenheit, or warmer, and that warm water has to go down deep.
Why Do Storm Names Get Retired?
Strong storms get names so people can talk about them quickly and clearly. If a storm causes terrible damage, its name is retired out of respect, like retiring a sports jersey.
Why Does the Sky Turn Greenish Before Some Storms?
Sometimes the sky turns an eerie green before a strong storm. Huge, thick storm clouds scatter sunlight in odd ways, and that can tint the sky greenish.
Why Do Power Lines Go Out in Storms?
Electricity travels along power lines on tall poles, and storms can hit those lines hard. Strong wind can knock down trees and poles, and lightning can send a surge through the wires.
Why Do Weather Sirens Howl?
A weather siren is a giant outdoor loudspeaker. Its job is to warn people outside when dangerous weather is near, so they can get to shelter quickly.
Why Is Shelter in a Basement Safer in a Tornado?
In a tornado, the biggest danger is flying debris, like broken glass, boards, and branches. A basement or a low interior room puts more walls and floors between you and that debris.
Why Do Flash Floods Happen So Quickly?
A flash flood is a flood that arrives fast, with little warning. Very hard rain can fall faster than the ground and drains can soak it up, so the water has nowhere to go.
Why Should You Never Drive Into Flooded Streets?
Floodwater is much more powerful than it looks. Just about 30 centimeters, or about a foot, of moving water can float many cars.
Why Do Blizzards Make It Hard to See?
A blizzard is a snowstorm with strong winds and very low visibility. The wind blows snow around so much that the sky and the ground blend together into one white blur.
Why Do Ice Storms Coat Everything in Glass?
An ice storm happens when rain freezes the moment it touches something cold. It paints every branch, wire, and road with a smooth layer of ice that looks like glass.
Why Do Grown-Ups Say “When Thunder Roars, Go Indoors”?
Thunder is the sound of lightning, so if you can hear thunder, lightning is close enough to be dangerous. Lightning can strike many kilometers away from the storm, even when the sky overhead looks blue.
Why Does Wind Blow at All?
Wind is simply air that is moving. The Sun heats the Earth unevenly, so some places warm up fast and others stay cooler.
Why Is a Breeze Soft and a Gale Strong?
Wind is air moving from high pressure to low pressure. If the pressure difference is small, you feel a soft breeze.
Why Do Flags Flap and Pinwheels Spin?
You can't see wind, but you can see what it does. Moving air pushes on a flag's fabric and on a pinwheel's blades, so they flap and spin.
Why Do We Feel Wind More on Hills and Beaches?
Wind feels stronger on hills and beaches because there is less in its way. Cities and forests slow the wind down with buildings and trees.
Why Does Wind Have Directions Like North and West?
We name wind by where it comes from, not where it is going. A north wind blows from the north toward the south.
Why Do Weather Vanes Point Into the Wind?
A weather vane is an old-fashioned wind detector that sits on a roof or barn. It spins freely, and the pointer end turns to face into the oncoming wind.
Why Does High Pressure Often Mean Fair Weather?
High pressure often means fair weather. In a high-pressure area, the air is sinking, and sinking air discourages clouds from growing.
Why Does Low Pressure Often Mean Storms?
Low pressure often means stormier weather. In a low-pressure area, air is rising, and rising air cools and builds clouds.
Why Do Isobars Look Like Squiggly Lines on Maps?
Isobars are lines on a weather map that connect places with the same air pressure. Pressure changes from place to place in curvy ways, so the lines wiggle and curl, just like the lines on a hiking map.
Why Do H and L Letters Appear on Weather Maps?
On a weather map, a big H marks the center of an area of high pressure. A big L marks the center of an area of low pressure.
Why Do Fronts Look Like Triangles and Semicircles?
A front is the boundary between two different air masses, one cold and one warm. On weather maps, fronts are drawn with a line and little shapes.
Why Does a Cold Front Often Bring Sudden Showers?
A cold front is where cold air pushes into a warmer area. Cold air is heavier, so it shoves under the warm air and lifts it upward quickly.
Why Does a Warm Front Bring Longer, Gentler Rain?
A warm front is where warm air slowly moves in over cooler air. Warm air is lighter, so it glides up over the cool air like a gentle ramp.
Why Do Jet Streams Race High Above Us?
Jet streams are fast rivers of wind high up in the sky. They blow about 9 to 12 kilometers above the ground, which is where airplanes cruise.
Why Do Airplanes Care About Wind?
Airplanes fly through moving air, so wind matters a lot to them. A tailwind pushes a plane from behind and speeds the trip.
Why Does Wind Chill Make You Feel Colder?
Wind chill is how cold the air feels on your skin when the wind is blowing. Wind steals heat from your skin faster, so the same temperature feels colder.
Why Do Deserts Get Hot Days and Cold Nights?
Deserts can be scorching hot during the day and surprisingly cold at night. Dry air and clear skies let heat escape into space after sunset.
Why Do Cities Feel Warmer than Countryside?
Cities are often warmer than the countryside around them. Pavement, roofs, and buildings soak up the Sun's heat and release it slowly in the evening.
Why Do We Measure Wind in Knots or Mph?
Wind speed can be measured in different units, just like distance can be measured in kilometers or miles. On land, many places use miles per hour or kilometers per hour.
Why Do Anemometers Spin?
An anemometer is a tool that measures how fast the wind is blowing. A common kind has three or four little cups on arms.
Why Do Barometers Help Forecast?
A barometer is a tool that measures air pressure. Air pressure goes up and down as weather systems move in and out.
Why Do Weather Apps Show Different Numbers?
Two weather apps can show different numbers for the same time and place. That is because they can use different computer models, different weather stations, and different update times.
Why Do Satellites Watch Earth From Space?
Weather satellites are like cameras and thermometers in space, looking down at the Earth. From high above, they can see huge storms, clouds, and temperatures all at once.
Why Do Doppler Radars See Rain Before It Arrives?
Doppler radar sends out pulses of radio waves and listens for the echoes that bounce back. Raindrops, hail, and snow bounce those waves back, so radar can see precipitation far away, often more than 100 kilometers.
Why Do Meteorologists Still Go Outside?
Meteorologists have amazing tools, like satellites, radar, and computers. But people still go outside to launch balloons, check instruments, and use their own eyes.
Why Do We Have Seasons?
We have seasons because the Earth is tilted as it travels around the Sun. The tilt changes how directly sunlight hits your part of the world as the year goes on.
Why Is Summer Hotter than Winter Where You Live?
Summer is hotter because of a tilt! Earth leans as it travels around the Sun.
Why Are Seasons Flipped in the Other Hemisphere?
Seasons are flipped because Earth is tilted, like a giant teeter-totter. When the north leans toward the Sun, the south leans away.
Why Does the Sun Feel Stronger at Noon?
The Sun feels stronger around noon because it is at its highest point in the sky. When the Sun is high, its light takes a shorter path through the air, so less light is lost along the way.
Why Do Long Summer Days Feel Endless?
Long summer days feel endless because the Sun really does stay up longer! Earth's tilt points your half of the world toward the Sun in summer, so the Sun is above the horizon for many extra hours.
Why Do Short Winter Days Feel Cozy and Dark?
Winter days are short because your part of Earth is tilted away from the Sun. The Sun stays low and is up for fewer hours, so sunset comes early and darkness arrives sooner.
Why Do Leaves Change Color in Autumn?
Leaves change color in autumn because trees stop making green chlorophyll. Shorter days and cooler weather tell trees to get ready for winter.
Why Do Some Places Stay Warm All Year?
Some places stay warm all year because their location keeps the sunshine strong all year long. Near the equator, the Sun stays high in the sky, and warm oceans help keep the heat steady.
Why Do the Poles Stay Cold?
The poles stay cold because sunlight reaches them at a low angle, and they spend months in darkness. Weak, slanted sunlight plus long polar nights is a recipe for a freezer belt.
Why Does the Equator Get So Much Heat?
The equator gets so much heat because the Sun stays high in the sky there most of the year. High Sun means strong, direct sunshine, so Earth's middle gets a big dose of energy.
Why Does Humidity Make Hot Days Feel Hotter?
Humid air makes hot days feel hotter because it slows down your body's cooling system. When you sweat, the sweat evaporates and takes heat away from your skin.
Why Does Dry Air Make Cold Days Feel Sharper?
Dry air makes cold days feel sharper because it pulls moisture out of your skin and lips. Cold air can't hold much water vapor, so winter air is often very dry.
Why Do Heat Waves Stick Around?
Heat waves stick around because of a stuck area of high pressure, sometimes called a heat dome. A high-pressure area can park over a region for days, and it keeps the hot air from moving away.
Why Do Cold Snaps Arrive So Suddenly?
Cold snaps arrive suddenly because a big mass of cold air can surge in behind a weather front. These cold air masses come from icy places, like near the poles or a snowy continent.
Why Does Snow Cover Keep the Ground Insulated?
Snow keeps the ground insulated because fluffy snow traps lots of tiny pockets of air. Air is a poor conductor of heat, so a snow blanket slows heat from escaping the soil.
Why Do Gardens Need Different Planting Months?
Gardens need different planting months because plants need the right mix of warmth, light, and no frost. Every place has its own pattern of seasons, so planting calendars follow local weather.
Why Do Birds Migrate with the Seasons?
Many birds migrate with the seasons to follow food and find safe weather for nesting. When winter makes insects and plants scarce, they travel to places with more food.
Why Do Bears and Other Animals Slow Down in Winter?
Bears and other animals slow down in winter because food is scarce and cold weather costs a lot of energy. Slowing the body down saves energy, so they can survive until spring.
Why Does Climate Mean More than Today’s Weather?
Weather is what the sky is doing today, and it can change from hour to hour. Climate is the long-term pattern of weather in a place, averaged over many years.
Why Do Scientists Track Climate Over Many Years?
Scientists track climate over many years because one lucky warm week can fool you. Long records show real trends, and they separate steady changes from random ups and downs.
Why Do Tree Rings and Ice Cores Hold Climate Clues?
Tree rings and ice cores hold climate clues because they store a yearly record of the past. Each year, a tree adds a ring and the ice adds a layer, and both are shaped by that year's weather.
Why Can One Hot Day Not Prove the Climate Is Changing?
One hot day can't prove the climate is changing because one day is just weather. Weather jumps up and down naturally, so scientists look for long patterns across many places and many years.
Why Do Oceans Store So Much Heat?
Oceans store so much heat because water can hold a huge amount of heat energy. They soak up energy from the Sun and release it slowly, which shapes climates around the world.
Why Do Volcanoes Temporarily Cool the Planet?
Big volcanic eruptions can cool the planet for a while because they launch tiny particles high into the sky. Those particles reflect some sunlight back to space, like a planetary sunscreen.
Why Does Caring for Earth Help Weather and Climate?
Caring for Earth helps weather and climate because healthy air, water, and nature support a steady, safer world. Trees cool the air, wetlands soak up floods, and clean energy and less waste add less pollution.
Why Is the Daytime Sky Blue?
The daytime sky is blue because air scatters blue light more than other colors. Sunlight looks white, but it is really a mix of all the rainbow colors.
Why Do Sunsets Glow Orange and Pink?
Sunsets glow orange and pink because the Sun's light has to travel through much more air to reach you. Along that long path, most of the blue light is scattered away.
Why Does the Sky Look Redder After Wildfires or Dust?
The sky looks redder after wildfires or dust storms because extra tiny particles in the air change the light. Smoke and dust scatter and filter sunlight, taking out blues and greens and letting the reds and oranges through.
Why Do Rainbows Need Both Sun and Rain?
Rainbows need both sun and rain because sunlight has to pass through raindrops to make colors. Each raindrop bends and reflects light, and splits it into colors.
Why Is a Rainbow Curved?
A rainbow is curved because every raindrop sends colors back to you at a specific angle. All the drops at that same angle from your eyes form a circle in the sky.
Why Do Rainbows Show a Set Order of Colors?
Rainbows show a set order of colors because each color bends by a slightly different amount. Red bends least and violet bends most, so they leave the raindrop at slightly different angles.
Why Can You Sometimes See a Double Rainbow?
You sometimes see a double rainbow because light can bounce twice inside raindrops. The second bounce makes a fainter bow outside the main one, and its colors are reversed.
Why Can’t You Walk to the End of a Rainbow?
You can't walk to the end of a rainbow because a rainbow isn't a place. It depends on where you stand and where the Sun is.
Why Do Soap Bubbles Show Rainbow Colors?
Soap bubbles show rainbow colors because their walls are incredibly thin, and light waves interact inside them. Some colors cancel out, and others get stronger, creating shimmering swirls.
Why Do Oil Slicks Shimmer Like Tiny Rainbows?
Oil slicks shimmer like tiny rainbows because a very thin layer of oil on water works like a bubble wall. Light bounces off the top and bottom of the oil film, and the waves interfere.
Why Does Moonlight Look Silvery, Not Yellow-Hot?
Moonlight looks silvery because the Moon only reflects sunlight, and it reflects just a small part of it. The Moon's gray surface is dim, so by the time the light reaches your eyes, it is very faint.
Why Do Stars Twinkle?
Stars twinkle because their light passes through Earth's moving, bumpy air before it reaches your eyes. The air bends starlight a little, and the bending changes quickly, which makes the star seem to shimmer.
Why Does the Moon Have a Halo Sometimes?
The Moon has a halo sometimes because ice crystals high in the sky bend its light into a ring. These crystals are in thin, high clouds called cirrus clouds.
Why Do Sundogs Appear Beside the Sun?
Sundogs are bright, glowing spots that sometimes appear on both sides of the Sun. They form when sunlight shines through tiny flat ice crystals floating in thin, wispy clouds high in the sky.
Why Does the Sky Look Purple Before a Storm?
Sometimes the sky turns a moody purple before wild weather arrives. Thick storm clouds and tiny bits in the air scatter and soak up sunlight in odd ways.
Why Do Shadows Get Long in the Evening?
In the evening your shadow can stretch out like a giant, many times taller than you! A shadow forms when your body blocks sunlight.
Why Does Snow Look So Bright White?
Fresh snow can look dazzling on a sunny day! A snowflake is a tiny ice crystal with lots of flat, shiny sides.
Why Do Clouds Turn Pink at Sunrise?
At sunrise, clouds can glow in soft pink, like a blush on the sky. When the Sun is low, its light has a very long trip through the air.
Why Does Twilight Linger After Sunset?
After the Sun sets, the sky does not turn black right away. That soft glow is called twilight.
Why Do Northern Lights Paint the Night (Aurora)?
Sometimes the night sky near the poles shimmers with green and pink ribbons called the aurora. Charged particles from the Sun crash into gases in the air high above Earth.
Why Do Mirages Shimmer on Hot Roads?
On a hot day, a faraway road can look wet and shiny even when it is completely dry. That trick is called a mirage.
Why Does Glass Make Light Bend?
Look through a glass of water, and a straw can seem broken or bent! Light slows down when it travels into glass or water.
Why Do Sunglasses Help on Bright Days?
On a bright day, you squint and your eyes feel tired and glary. Good sunglasses make the light dimmer and cut down glare, and the right ones also block harmful UV rays.
Why Does a Prism Split White Light?
Shine a flashlight through a prism, and a rainbow pops out of the other side! White light is secretly a team of colors.
Why Do Photographers Chase “Golden Hour”?
Photographers love the time just after sunrise and just before sunset. It is called golden hour.
Why Do Weather Forecasts Help Families Plan?
Should you pack a raincoat, or sunscreen? A forecast helps you decide!
Why Are Forecasts Better for Tomorrow than Next Month?
A forecast for tomorrow is usually very good, but a forecast for next month is mostly a guess. The atmosphere is chaotic, so tiny errors in our measurements grow bigger as time goes by.
Why Do Weather Stations Sit in Open Spots?
Weather stations measure the air, and they sit out in wide open spaces. Buildings, trees, and hot pavement can change the wind, rain, and temperature around them.
Why Do Kids’ School Apps Send Weather Alerts?
Sometimes your family's phone buzzes with a weather alert, even when the sky looks calm. An alert pings when a watch or warning affects your area.
Why Should You Respect a Severe Weather Watch?
A severe weather watch means dangerous weather could happen soon, even if the sky looks fine right now. Conditions are right for storms to form.
Why Is a Warning More Urgent than a Watch?
A watch says storms could happen. A warning says danger is happening now, or is about to.
Why Do We Practice Storm Drills?
Drills teach your body and brain exactly what to do before a storm arrives. Practicing makes the steps feel familiar.
Why Is a Weather Radio Still Useful?
Phones are handy, but a weather radio has a special job. It listens for official weather alerts and announces them day and night.
Why Pack a Small Go-Bag Before Storm Season?
A go-bag is a small bag, packed ahead of time, with things your family might need in a storm. If you ever have to shelter or leave with grown-ups, you will not need to scramble around.
Why Stay Away From Windows in a Big Storm?
In a big storm, one of the safest rules is to stay away from windows. Strong wind can throw branches and other objects through glass.
Why Unplug Gadgets Before Lightning Arrives?
Lightning is incredibly powerful, and it can zap electronics even if it does not hit your house directly. A lightning surge can race through wires and fry gadgets.
Why Wear Layers on Changeable Spring Days?
Spring can start out chilly, turn warm by lunch, and get windy or rainy in the afternoon! Layers of clothes trap warm air, and you can add or remove them as the weather changes.
Why Drink Water on Hot, Humid Days?
On a hot, sticky day, your body works extra hard to stay cool. It sweats, and that sweat is mostly water that leaves your body.
Why Never Play in Drainage Ditches After Rain?
A ditch after a rainstorm might look like a fun place to splash. It is not safe!
Why Check the Sky Before a Picnic or Hike?
A picnic or hike is much more fun when you are not caught in a storm. Storm clouds can build fast, and you might be far from shelter.
Why Do Farmers Watch the Weather So Closely?
Farmers spend their days outdoors, and the weather is like their daily boss. Rain, frost, heat, and wind decide when to plant, water, and harvest, and how to care for animals.
Why Do Pilots and Sailors Need Forecasts?
Airplanes and ships travel for hours across big open spaces, and weather changes along the way. Pilots and sailors need to know about wind, waves, clouds, and storms before they leave.
Why Can Citizen Scientists Help Weather Research?
You do not need a lab coat to help real scientists. Volunteers report rain, snow depth, and sky conditions from their own backyards.
Why Keep a Simple Weather Journal?
A weather journal is a notebook where you write down what the sky is doing each day. Writing trains your eyes to notice details like temperature, clouds, and wind.
Why Learn Local Emergency Signals?
Many towns have special ways to warn people about danger, like sirens, text alerts, and radio or TV messages. Each signal has a meaning, and the meanings can differ from place to place.
Why Help Neighbors After a Storm (with Grown-Ups)?
After a storm passes, people nearby might have a hard time. Some neighbors need a check-in, some need help with small clean-up, and some need to charge a phone.
Why Clean Gutters and Secure Trampolines Before Wind?
Before a windy, rainy storm, grown-ups often clear gutters and tie down trampolines. Blocked gutters can overflow, and loose objects can be flung by the wind.
Why Is Sunscreen Still Useful on Cloudy Days?
A gray, cloudy day can fool you into thinking you cannot get sunburned. Clouds block some light, but a lot of the invisible UV rays can still get through.
Why Talk About Feelings After Scary Storms?
Loud thunder and howling wind can leave kids with big feelings, and that is completely normal. Your brain remembers scary moments, and talking helps it sort them out.
Why Does Asking “Why?” Make You a Weather Detective?
Every time you ask why, you become a detective hunting for clues in the sky. Asking why makes you notice details, test ideas, and stay careful.
From Book 1: The Great Expedition (8)
Why Does It Rain? Follow the Water Cycle!
Rain is one stop on the water cycle! The Sun heats water in oceans, lakes and rivers, and it turns into invisible vapor that rises into the air.
Why Does Thunder Follow Lightning? Light Wins the Race!
Flash first, boom later! A lightning bolt is super hot and heats the air around it to hotter than the surface of the Sun.
Why Do Rainbows Appear? Light Bends and Splits!
Rainbows look like magic, but they come from light, water and a little science. Sunlight shines into tiny drops of water in the air, bends and splits into all its...
Why Do Caves Form? Rain, Rock and Slow Drips!
Caves are nature's underground architecture. Rain picks up carbon dioxide and becomes a weak carbonic acid, which seeps into the ground and slowly dissolves limestone along cracks until they become channels and passages.
Why Do Hurricanes Spin? Ocean Heat and Earth's Twist!
Hurricanes are powered by warm ocean water. Heat makes moist air rise, which creates low pressure, and cooler air rushes in to take its place.
Why Is Every Snowflake Different? One of a Kind!
Snowflakes all follow one family rule but each one turns out different. A snowflake begins as a tiny ice crystal in a cloud and grows by collecting water vapor as it falls.
Why Do Clouds Stay Up? They're Made of Tiny Drops!
Clouds look like fluffy cotton, but they are made of billions of tiny water droplets. Warm air rising from the ground helps hold those tiny droplets up.
Why Is Lightning So Hot? Big Energy in a Tiny Strike!
Lightning is a giant electric current that races through the air in an extremely narrow channel. The page says that channel can reach about 30,000 degrees C (54,000 degrees F).
From Book 2: The Inside Expedition (6)
Why Do We See Faces in Clouds?
Have you ever looked up and seen a smiling face in a cloud? The brain is a face-finder!
Why Do Eyes Water in the Wind?
Wind can make your eyes water, even when you are not sad. Wind dries the front of your eye.
Why Does Weather Change?
Have you noticed that one day is sunny, and the next day is rainy? Air is always on the move!
Why Does It Rain?
Have you ever watched a big gray cloud open up and pour? Clouds get too heavy!
Why Does the Wind Blow?
Have you ever felt a breeze on a hot day, or flown a kite? Air rushes to fill a gap!
Why Are There Clouds?
Have you ever looked up and found a cloud shaped like an animal? Clouds are tiny water drops in a crowd!
From Book 3: The Built Expedition (3)
Why Do Sailboats Need Wind?
Sails catch moving air, and the wind can push the boat from behind. Wind can also flow over a curved sail and pull it forward.
Why Do We See Lightning Before Thunder?
Lightning and thunder start together. Light reaches your eyes almost instantly.
Why Does a Kite Need Wind?
A kite is like a wing on a string. Moving air hits its tilted face and slides over the top.
From Book 4: The Wild Expedition (14)
Why Do Mushrooms Pop Up After Rain?
The mushroom you see is only the fruit of a fungus. The real fungus is a hidden web in the soil.
Why Do Worms Come Out After Rain?
Wet ground fills the worm's tunnels with water. Worms breathe through damp skin, and coming up is often easier than staying in a flooded tube.
Why Do Frogs Croak After Rain?
Rain makes the world safer for frog eggs! Many male frogs croak after a storm to call females to fresh pools.
Why Do Clouds Look Fluffy?
A fluffy cloud is a crowd of tiny water drops or ice crystals floating together! From the ground, the crowd looks like cotton, because light bounces off all those drops.
Why Does Rain Fall?
Cloud drops start out tiny! When they bump into each other and grow heavy enough, the air can't hold them up anymore.
Why Does Thunder Follow Lightning?
Lightning is a giant spark! It heats the air so fast that the air explodes outward.
Why Does the Wind Blow?
Wind is air on the move! The sun warms some places more than others.
Why Do We See Rainbows?
A rainbow is sunlight split apart and sent back by raindrops! Each drop acts like a tiny prism and a tiny mirror at the same time.
Why Does Fog Hug the Ground?
Fog is a cloud that formed at ground level! When cool air near the ground makes water vapor condense, you get tiny drops that you can walk through.
Why Does Snow Sparkle?
Snow is a pile of tiny ice crystals! Their flat faces act like little mirrors.
Why Does Frost Paint the Grass?
Frost is dew's frozen cousin! When grass gets colder than freezing, water vapor can turn straight into ice crystals on the blades.
Why Do Storms Have Calm and Wild Parts?
A storm is like a weather engine with different rooms! Rising warm air, falling rain, and spinning winds are not the same in every spot.
Why Can a Weather Forecast Miss?
Weather is a giant puzzle with too many moving pieces! A forecast is the best science guess from computer models, satellites, and radars.
Why Do Frogs Croak After Rain? The Pond Chorus
Rain makes travel and breeding easier for frogs. Wet ground does not dry out their skin, and puddles and ponds fill up.
From Book 5: The Time Expedition (2)
Rock Breakers! Why Does Weather Break Rock?
Rain gets into tiny cracks in rock. When that water freezes, it turns into ice and takes up more space, which pushes the crack wider.
Crack and Crumble! Another Look: How Weather Breaks Rock
Rock is tough, but weather works on it slowly. Water, wind, heat, and cold can all wear it down, and even plant roots can push into cracks.
From Book 6: The Ocean Expedition (4)
Why Is a Weather Buoy Left Alone in the Ocean?
A weather buoy is a floating robot weather station. It sits in the ocean for months, measuring wind, waves, temperature, and air pressure.
Why Do Hurricanes Grow Over Warm Ocean Water?
A hurricane is like a giant heat engine, and warm ocean water is its fuel. Warm seawater evaporates and rises as moist air.
Why Does a Storm Surge Flood a Coast?
A storm surge is seawater pushed onto land by a storm's strong winds and low air pressure. It isn't just rain!
Why Do Wetlands Protect Towns From Storms?
Wetlands, like salt marshes and mangroves, act like a sponge and a speed bump for storm water. They are places where land and sea mix.
From Book 8: The Space Expedition (7)
Why Do Nebulae Look Like Colorful Clouds?
Nebulae look like colorful clouds because they really are giant clouds of gas and dust in space! Hot stars light them up, or dark dust lanes make shadowy shapes, painting pinks, blues, and glowing shapes for telescopes.
Why Is There Almost No Weather on the Moon?
There is almost no weather on the Moon because it has almost no air! The Moon's gravity is too weak to hold a thick atmosphere, so there is no wind, rain, or clouds, only silent, dusty stillness.
Why Does Neptune Have the Fastest Winds in the Solar System?
Neptune has the fastest winds because its own inner heat stirs its thick atmosphere! Neptune gets very little sunlight, yet its winds blow up to about 2,000 kilometers per hour.
Why Does Solar Wind Shape a Huge Bubble Around the Planets?
The Sun blows a stream of charged particles into space called the solar wind. It pushes outward so far that it inflates a huge bubble around the planets, called the heliosphere.
Why Do Launches Pause for Weather Sometimes?
Launches pause for weather because lightning, strong winds, and clouds can endanger rockets and crews! Range safety teams wait for safer skies.
Why Do Spectroscopy Rainbows Reveal Star Recipes?
Spectroscopy rainbows reveal star recipes, because gases leave fingerprint lines in starlight! When you spread starlight into a rainbow, dark or bright lines appear.
Why Can a Solar Storm Bother Satellites and Power Grids?
A solar storm can bother satellites and power grids because it sends out charged particles! A burst of charged particles from the Sun can jostle Earth's magnetic field and disturb satellites, radio, and power lines.
From Book 9: The Food Expedition (3)
Why Are Ice Cubes Cloudy in the Middle?
Ice cubes are cloudy in the middle because freezing pushes tiny bubbles of air to the center! Water freezes from the outside in, and the air and minerals that were dissolved in the water get squeezed toward the middle.
Why Does Pasta Water Get Cloudy?
Pasta water gets cloudy because starch leaks out of the noodles! Those tiny starch bits float in the water and make it look milky.
Why Do Carrots Taste Sweeter After a Frost?
Carrots taste sweeter after a frost because the cold makes them turn stored starch into sugar! Starch tastes plain, but sugar helps protect the carrot from freezing.
From Book 11: The Animal Expedition (2)
Why Do Starlings Fly in Giant Swirling Clouds?
Starlings fly in giant swirling clouds because each bird copies its closest neighbors! There is no leader at all.
Why Do Polar Bears Dig Snow Dens?
Polar bears dig snow dens because snow is a great blanket for newborn cubs! Mother bears dig the dens in big snowdrifts, and outside it may be freezing while inside stays much warmer.
From Book 12: The Volcano Expedition (5)
Why Do Eruptions Make Tall Umbrella-Shaped Ash Clouds?
Big eruptions blast hot gas and ash high into the sky. The cloud rises because it is hotter and lighter than the air around it, then spreads out at the top like an umbrella!
Why Do Volcanoes Make Lightning in Ash Clouds?
Inside a big ash cloud, bits of ash and ice bump into each other. The rubbing builds up electric charge, just like static electricity.
Why Do Past Eruption Deposits Guide Future Forecasts?
Past eruption deposits guide forecasts because volcanoes tend to repeat their habits. Layers of old lava and ash show where eruptions went and how big they were.
Why Do Airplanes Avoid Ash Clouds?
Airplanes avoid ash clouds because volcanic ash is made of tiny pieces of rock and glass. Inside a hot jet engine, that ash can melt and stick.
Why Do Farmers Watch Wind Forecasts Around Vents?
Farmers watch wind forecasts around vents because wind carries ash and decides where it falls. Wind is the delivery truck for ash.
From Book 13: The Light Expedition (12)
Why Are Shadows on Snow Sometimes Blue?
Shaded snow looks blue because it is lit by the blue sky instead of direct sunshine. The sky scatters blue light in every direction, and that light fills the shadow.
Why Does Snow Melt First Around a Dark Rock?
Dark rocks soak up more of the Sun's light than bright snow does. They turn it into heat and melt the snow right next to them.
Why Is a Cloudy Day Outside Still Brighter than a Lit Room Inside?
The Sun is so powerful that even through thick clouds, daylight is much stronger than room lights. Outdoors on a cloudy day, the light can be 10 to 100 times brighter than a lamp indoors!
Why Do Shadows Disappear on Cloudy Days?
Direct sunlight comes from one small, bright spot, so it makes sharp shadows. Clouds spread the sunlight across the whole sky.
Why Can You See the Shadow of a Cloud Sliding Across a Field?
A cloud blocks sunlight and casts a shadow on the ground below it. The wind pushes the cloud along, so its shadow glides across the field.
Why Do Beams of Sunlight Fan Out From Behind a Cloud?
Gaps in a cloud let sunlight shine through in beams. The beams look like they fan out from the cloud, but they are really parallel.
Why Does a Calm Lake Show a Mirror Picture and a Windy Lake Does Not?
Still water is flat, so it reflects light in an orderly way and makes a clear, upside-down picture. Wind and ripples tilt the surface into many little slopes.
Why Does Frosted Glass Hide Shapes but Still Let Light In?
Frosted glass has a rough surface covered in tiny bumps. Light still gets through, but each bump bends it in a different direction, so the picture gets scrambled.
Why Does Frost Sparkle?
Frost and fresh snow are made of tiny ice crystals with flat, shiny faces. Each face works like a little mirror.
Why Is Muddy Water Cloudy?
Muddy water is full of tiny bits of dirt that float around. Each bit bounces some of the light in a new direction, so light gets scattered before it can travel far.
Why Are Some Plastics Clear and Others Cloudy?
Clear plastics have molecules arranged so that light can pass through without much scattering. Cloudy plastics have tiny crystals or added particles that bounce light around.
Why Does a Flashlight Look Weaker in Fog or Rain?
A flashlight looks weaker in fog or rain because tiny water drops scatter the light! Each drop bounces some light in every direction.
From Book 14: The Sound Expedition (6)
Why Does Fresh Snow Make Everything Sound So Quiet?
Fresh snow makes everything sound quiet because it soaks up sound! It is full of tiny air pockets between the flakes.
Why Do Foghorns Make Deep Sounds?
Foghorns make deep sounds because low sounds travel farther! Low sounds also bend around obstacles.
Why Do Longer Wind-Chime Tubes Ring Lower?
Longer wind-chime tubes ring lower because each wiggle takes more time! A longer tube vibrates more slowly.
Why Does Rain Sound Louder on a Metal Roof than on Grass?
A metal roof acts like a giant drum when raindrops land on it! The whole thin sheet vibrates, and the sound spreads out.
Why Does Wind Howl Around a House?
Wind howls when it swirls around corners and wires! The swirls peel off one after another at a steady rate.
Why Does Snow Squeak When It Is Very Cold?
Snow squeaks in very cold weather because the crystals are hard and dry! When you step on them, they crush and rub in rapid-fire.
From Book 15: The Robot Expedition (1)
From Book 16: The Desert Expedition (22)
Why Are Desert Sand Grains So Round and Frosted?
Wind bounces sand grains along the ground, and every bump rubs off their sharp corners! After thousands of years of tumbling, the grains become round with a dull, frosted surface.
Why Do Desert Rocks End Up in Strange Wind-Carved Shapes?
Wind carries sand that acts like natural sandpaper, and it slowly carves rocks into strange shapes! Softer layers wear away faster than harder ones.
How Does a Beetle Collect Drinking Water From Fog?
In the Namib Desert, fog rolls in from the ocean at dawn, and some beetles use it to drink! Fog droplets gather on the beetle's bumpy back.
Why Does Snow Sometimes Fall in Deserts?
Snow can fall in deserts because deserts can be high up! The higher you go, the colder the air gets.
Why Are There So Few Clouds Over Most Deserts?
Many deserts lie where air sinks down from high in the sky! Sinking air warms up and dries out, so clouds rarely form.
How Do Plants Survive in Places Where It Almost Never Rains?
Desert plants survive with clever tricks for finding, saving, and waiting for water! Some store water in their stems, some grow long roots, and some wait as tiny seeds.
Why Do Desert Wildflowers Bloom All at Once After a Rare Rain?
Desert wildflowers bloom all at once because rain wakes up millions of seeds together! The seeds wait in the soil for enough water and mild weather.
How Can a Seed Wait for Years Until It Rains?
A desert seed can wait for years, because it has a tough coat and a rain sensor! Chemicals in the coat keep the seed from sprouting too soon.
Why Does the Creosote Bush Smell Like Rain?
The creosote bush smells like rain because its leaves release a fresh scent when they get wet! The smell comes from oils in a waxy coating on the leaves.
Why Does the Ocotillo Grow Leaves Only After It Rains?
The ocotillo grows leaves only after it rains, so it does not waste water! Most of the year, it looks like a bundle of dead sticks.
How Do Desert Tortoises Survive Years of Dry Weather?
Desert tortoises survive years of dry weather by hiding in burrows and storing water! They drink a lot when they can, then use that water for months.
Why Do Fairy Shrimp Hatch From Dry Dust After a Rain?
Fairy shrimp hatch from dry dust after a rain, because their eggs are made to wait! The eggs have thick shells and can sit dry for many years.
How Do Desert Elephants Live Where It Hardly Ever Rains?
Desert elephants live where it hardly ever rains by walking far and digging for water! They remember where water can be found, even if it has been a long time.
Why Does Fog Roll Into Some Coastal Deserts?
Fog rolls into some coastal deserts because cold ocean water chills the air above it! Warm, moist air cools over the cold sea and turns into fog.
How Do Fog Nets Catch Water?
Fog nets catch water by letting tiny fog droplets stick to a mesh! People stretch big nets across hilltops in dry places like the Atacama Desert.
Why Do Desert Rains Come in Short, Heavy Storms?
Desert rains come in short, heavy storms because the hot ground makes warm air rise fast! The rising air cools, and a storm cloud forms quickly.
Why Does Rain Sometimes Disappear Before It Hits the Ground?
Rain sometimes disappears before it hits the ground because the air below the cloud is so dry! The falling drops evaporate on the way down.
Why Doesn’t Desert Soil Soak Up Rain Well?
Desert soil does not soak up rain well because it is often baked hard or sealed by a thin crust! There are also few plant roots to open channels for water.
What Is a Monsoon Season in a Desert?
A monsoon season is a time of year when winds shift and bring moist air to a dry place! In parts of the southwestern United States and Mexico, it happens in summer.
How Do Desert Animals Sense That Rain Is Coming?
Desert animals sense that rain is coming by noticing clues that people often miss! Changes in the air, smells, and sounds can all signal a storm.
How Can a Lake Appear in the Desert After a Big Rain?
A lake can appear in the desert after a big rain because heavy rain fills dry basins with shallow water! These lakes are rare, and they do not last.
How Do Tall Wind Towers Keep Desert Houses Cool?
Tall wind towers keep desert houses cool by catching breezes and sending them down into the house! People in parts of Iran and the Middle East call them windcatchers.
From Book 17: The Rainforest Expedition (9)
What Is a Cloud Forest?
A cloud forest grows high on a tropical mountain, where clouds drift right through the trees. The air is cool, damp, and misty all day long.
What Happens to a Raindrop on Its Way Down Through the Forest?
A raindrop hits the canopy first. Some drops cling to leaves and evaporate straight back into the air, while others drip from leaf to leaf or run down branches and trunks.
Why Does It Rain Almost Every Afternoon in Some Rainforests?
In some rainforests, it rains almost every afternoon like clockwork! In the morning, the Sun heats the forest and water evaporates into the air.
How Does a Rainforest Help Make Its Own Rain?
Trees pull water from the soil and release it as vapor through tiny pores in their leaves. This is called transpiration.
Why Does Mist Rise From the Forest After a Storm?
After a storm, the leaves, branches, and ground are warm and wet. When the Sun comes out, water evaporates into the cooler air above.
How Do Scientists Measure the Weather Inside a Rainforest?
Scientists set up tall towers topped with instruments, plus rain gauges and sensors on the forest floor. They measure temperature, humidity, wind, and the gases trees breathe in and out.
How Does a Forest Heal Itself After a Storm or Landslide?
After a storm or landslide, fast-growing pioneer plants, such as Cecropia trees and ferns, spring up in the open light. They shade the soil and make it better for others.
Can a Rainforest Change the Weather Far Away?
Yes! Scientists have found that moisture released by the Amazon travels with the wind.
How Do Insects and Frogs Take Advantage of the Rainy Season?
When the rains arrive, many frogs gather at fresh pools and breed. Insects also emerge in huge numbers, because fresh leaves and puddles provide food and places for eggs and young.
From Book 18: The Polar Expedition (13)
Why Is Antarctica So Windy?
Antarctica is so windy because cold, heavy air slides downhill off the high ice sheet like water flowing down a slope! Scientists call these katabatic winds.
Why Are Some Valleys in Antarctica Free of Ice and Snow?
Some valleys in Antarctica have no ice or snow because mountains block the glaciers and strong winds blow the snow away! They are called the McMurdo Dry Valleys.
Why Do Snowy Owls Have Feathers on Their Feet?
Snowy owls have feathers on their feet to wear built-in fluffy socks! The feathers trap warm air and keep skin from touching cold snow.
How Do Reindeer Find Food Under the Snow?
Reindeer find food under the snow by smelling it and digging for it! Even under a foot of snow, they can sniff out their winter snack.
How Do Lemmings Live Under the Snow?
Lemmings live under the snow in a cozy hidden world! When snow piles up, a space forms between the ground and the snow.
How Do Arctic Hares Hop Across Deep Snow?
Arctic hares hop across deep snow on big, furry back feet that work like snowshoes! The wide feet spread out the hare's weight.
What Are Snow Fleas?
Snow fleas are tiny black specks that hop around on the snow, but they are not real fleas! They do not bite people or pets.
Why Do Sled Dogs Curl Up in the Snow to Sleep?
Sled dogs curl up in the snow to sleep because it keeps them warm! Their thick coats, curled-up bodies, and bushy tails work together.
How Do Planes Land on Snow and Ice?
Planes land on snow and ice by using skis instead of wheels! Skis spread the plane's weight over a wide area, so it glides on top.
What Vehicles Drive Across Polar Snow and Ice?
Polar travelers use snowmobiles, tracked vehicles, and big tractors to cross snow and ice! Tracks and wide skis spread out weight so vehicles do not sink.
Why Don’t Skis Sink Into the Snow?
Skis do not sink because they spread your weight over a big area! Your weight is the same, but the push on each bit of snow is much smaller.
Why Do Eyelashes and Beards Get Frosty in the Cold?
Frosty eyelashes and beards come from your own warm breath! Your breath is full of invisible water vapor, which is water in the form of a gas.
How Do Weather Balloons Help Polar Scientists?
Weather balloons carry instruments high into the sky for polar scientists! Station staff release them every day.
From Book 19: The River Expedition (6)
How Can You Follow a Raindrop From Your Street to the Sea?
A raindrop that lands on your street takes a trip to the sea! It flows to the gutter, into a storm drain, and through pipes to a nearby creek or river.
How Do Forecasters Know a River Is About to Flood?
Forecasters know a river is about to flood by measuring rain, snow, and river height! They gather lots of clues and put them together in a computer.
Why Does Rain Run Off Pavement Faster than It Soaks Into Grass?
Rain runs off pavement faster than it soaks into grass because pavement cannot soak up water! Soil is full of tiny spaces that act like a sponge.
How Can You See a Drought in a River?
You can see a drought in a river because the water gets low and rocks poke out! A drought is a long time with much less rain and snow than normal.
How Do Scientists Tell How Cloudy a River Is?
Scientists tell how cloudy a river is by measuring how much light gets through! Cloudy water is called turbid, and the cloudiness is called turbidity.
What Is a Rain Garden?
A rain garden is a shallow, planted dip in the ground that collects rain! Instead of rushing into a storm drain, the water soaks in slowly.
From Book 20: The Mountain Expedition (32)
Why Is There Snow on a Mountain Near the Equator?
Mount Kilimanjaro in Tanzania sits close to the equator, where the land is hot, yet it still has snow on top! The secret is height.
Why Does Some Mountain Snow Turn Pink?
Some mountain snow turns pink because of tiny living things called algae! In late spring and summer, they wake up in the melting snow.
How Do Snow Leopards Live in Cold Mountains?
Snow leopards live in cold mountains thanks to a built-in winter outfit! They have thick fur, wide furry paws, and a long tail.
How Does a Ptarmigan Survive in a Snow Burrow?
A ptarmigan survives cold nights by tucking into a snow burrow! It sounds chilly, but snow is a great blanket.
How Can a Flower Bloom Through Snow?
A flower can bloom through snow because it gets a head start under the snow! Some alpine plants store food in underground bulbs all year long.
How Do Mountain Animals Find Food When Snow Covers Everything?
When snow covers everything, each mountain animal has its own food plan! Some store food, some sleep, and some dig.
How Do Scientists Count Animals on Steep, Snowy Slopes?
Scientists count animals on steep, snowy slopes using clever tools from far away! Climbing close to wild animals can be risky for people and can scare the animals.
Why Does Wind Roar Through Mountain Passes?
Wind roars through mountain passes because the air gets squeezed through a narrow gap! A pass is a low spot between two peaks.
Why Does the Wind Blow Uphill During the Day and Downhill at Night?
Mountain winds switch directions between day and night! In the day, the wind often blows uphill.
What Is a Lenticular Cloud?
A lenticular cloud is a smooth, round cloud shaped like a lens! Some people think it looks like a flying saucer.
What Is a Banner Cloud?
A banner cloud streams from a mountain peak like a flag flying in the wind! It appears on one side of a steep, pointed mountain.
Why Do Hikers Start Early to Avoid Afternoon Storms?
Hikers start early to avoid afternoon storms that build in the mountains! Mornings are usually calm and clear.
How Does a Mountain Range Squeeze the Rain Out of the Wind?
A mountain range squeezes the rain out of the wind like squeezing a wet sponge! Moist wind is forced to climb up the mountains.
What Is the “Snow Eater” Wind That Melts Snow in Hours?
The snow eater wind is called a chinook, and it melts snow in hours! A chinook is a warm, dry wind that blows down the eastern side of the Rocky Mountains.
Why Can Mountain Weather Change So Fast?
Mountain weather can change fast because mountains stir up the air! Air is forced to rise, sink, and swirl around peaks and valleys.
Why Does It Snow So Much More in the Mountains than in the Valleys?
It snows so much more in the mountains because rising air cools and drops its water! Mountains push moist air upward.
What Is a Mountain Weather Station?
A mountain weather station is a robot helper that measures the weather for us! It sits on a peak or slope, powered by the Sun.
Why Can It Snow in July on a Mountain?
It can snow in July on a mountain because the air up high can be freezing, even in summer! The higher you go, the colder it gets.
Why Is a Mountaintop a Bad Place to Be in a Thunderstorm?
A mountaintop is a bad place to be in a thunderstorm because lightning strikes tall, high places! On a bare peak, a person may be the tallest thing around.
Can You Walk Inside a Cloud?
Yes, you can walk inside a cloud! A cloud is just a mass of tiny water droplets, the same as fog.
Why Is It So Hard to Forecast Mountain Weather?
Mountain weather is hard to forecast because mountains make big changes in a short distance! A sunny valley and a stormy ridge may be only a few miles apart.
What Are the Tiny White Pellets That Fall in Mountain Storms?
The tiny white pellets that fall in mountain storms are called graupel! They look like tiny foam balls, and they are soft and crumbly.
How Does Snow Pile Up Into Layers on a Mountain?
Snow piles up into layers because every storm adds a new one! Between storms, wind, sunshine, and cold change the snow's surface.
Why Do Snow Scientists Dig Pits in the Snow?
Snow scientists dig pits so they can see inside the snowpack! A pit works like a window, because the wall shows every layer in a cross-section.
Why Does a Whole Layer of Snow Sometimes Let Go and Slide?
Sometimes a whole layer of snow lets go because it is sitting on a weak layer underneath. When it slides all at once, that is called an avalanche.
How Do Avalanche Forecasters Keep People Safe?
Avalanche forecasters keep people safe by studying the snow and the weather. Then they tell everyone how dangerous the mountains are that day.
Where Is the Line Above Which Snow Never Melts Away?
The snow line is the height above which snow stays on the ground all year. On a mountain, you may see a clear line where bare ground meets white snow in summer.
Why Is Snow in the Rockies So Light and Fluffy?
Snow in the Rockies is often light and fluffy because the air there is very cold and dry. Skiers love it, and they call it powder, because it feels almost like flour.
How Can Scientists Measure Snow in Inches of Water?
Scientists can measure snow in inches of water because snow is mostly air. They find out how much water is hidden inside the snow.
How Do Ski Areas Make Snow?
Ski areas make snow with machines called snow guns. They spray tiny droplets of water into very cold air.
Why Do Skis Slide So Well on Snow?
Skis slide so well on snow because of a very thin layer of water. It forms on the surface where the ski rubs the snow.
Why Do Some Mountain Highways Have Long Roofs Called Snow Sheds?
Some mountain highways have long roofs called snow sheds. They protect the road from snow that slides down steep slopes, so cars and trucks can keep moving.
From Book 21: The Magnet Expedition (2)
What Happens When the Solar Wind Hits Earth’s Magnetic Shield?
The Sun is always blowing a wind of tiny charged particles out into space. It is called the solar wind, and it blasts past Earth all the time.
Why Do Compass Needles Wiggle During a Magnetic Storm?
Sometimes the Sun throws out a giant burst of charged particles. When they hit Earth's magnetic field, they shake it, and that can make a compass needle wiggle.
From Book 22: The Energy Expedition (5)
How Does a Wind-Up Toy Store Energy?
A wind-up toy walks, hops, or rolls without a battery. The secret is a twisted metal spring inside.
How Much Power Does a Solar Panel Lose When Clouds Roll In?
Solar panels love sunshine. But clouds sometimes roll in and cover the sky.
How Does a Wind Turbine Turn Wind Into Electricity?
A giant wind turbine looks like a big pinwheel. It makes electricity from the wind.
Why Do Wind Farms Put Their Turbines So High Up?
Wind farms put their turbines way up high. They use tall towers and very long blades.
What Happens to Solar and Wind Power When the Sun Sets or the Wind Stops?
Solar panels make no power at night. Wind turbines slow down when the air is calm.
From Book 23: The Flight Expedition (7)
Why Do Airplanes Take Off Facing Into the Wind?
Pilots love taking off and landing into the wind. It might seem backward.
How Do Wind Tunnels Help Engineers Test Wings?
How do engineers test new wings before building a plane? They use a giant tube with a fan.
How Do Dandelion Seeds Sail on a Breath of Wind?
A dandelion seed sails away on a puff of wind. It looks like a tiny parachute.
What Happens When Lightning Strikes an Airplane?
Lightning can strike an airplane. That sounds scary!
How Can a Plane Land Safely in Thick Fog?
Fog can hide the runway completely. Can a plane still land?
Why Does a Weather Balloon Swell as It Rises, and Then Pop?
A weather balloon starts small. As it rises, it swells.
How Can You Tell Which Way the Wind Is Blowing?
Wind can be hard to see. But you can still find its path.
From Book 24: The Underground Expedition (3)
What is the frost line, and why are pipes buried below it?
In cold places, the ground freezes from the top down in winter. The frost line is the deepest point where the ground freezes.
Why does the ground smell so fresh after rain?
The smell has a name: petrichor. When raindrops hit dry soil, they trap tiny air bubbles that burst and send out a mist of smelly particles.
How does the Oak Ridges Moraine soak up rain like a giant sponge?
The Oak Ridges Moraine is a long ridge north of Toronto, built from sand and gravel that glaciers dropped about 12,000 years ago. Rain and melting snow soak through the...