Book 1 activities
Try it at home: 150 science activities from Book 1
Every page of A Million Whys Book 1 has a "Think like a scientist" idea. Here they are in one place, so you can pick one for the kitchen table, the bath, the backyard or a car ride. Each one links to its question page, with the video and the full answer.
Expedition 1: Your Amazing Body (25)
1. Why Do We Get Goosebumps? Tiny Muscles, Big Bumps!
Next time you get goosebumps, ask yourself: were you cold, scared, or excited? Where on your body did you notice them? Compare with a friend! Then write down your observations, and become a goosebump expert!
2. Why Does Your Heart Keep Beating While You Sleep?
Count your pulse and compare. Find your pulse on your wrist or your neck. Count the beats for fifteen seconds, then multiply by four. That's your beats per minute! For example, twenty beats times four is eighty. Try it while resting, and again after jumping. What changes? Your heart is always on the job, awake or asleep, keeping you amazing!
3. Why Do Onions Make You Cry? The Tiny Gas Trick!
Observe: what happens when you cut an onion? Does it change with different onions, like red, white or yellow? Try this, with a grown-up doing the cutting: stand way back, and cut a small piece. What do you notice? Record your results, like a real scientist! So next time an onion makes you cry, remember: it's just a clever plant protecting itself!
Do this with a grown-up4. Why Do We Hiccup? Meet Your Twitchy Diaphragm!
Next time you, or someone else, gets the hiccups, be a detective! Notice: what were you doing just before? Swallowing quickly? Laughing? Eating? Wonder: what do you think started the diaphragm twitch? Write down your clues, and look for a pattern! So a hiccup is just your diaphragm and vocal cords doing a funny little dance. Hic!
5. Why Do We Sneeze? Your Nose's Super Reflex!
Next time you feel a sneeze coming on, pay attention. Notice your face scrunch, your eyes squeeze shut, and your nose wrinkle up. Your body is preparing for launch! What happens right before your big ah-choo? Write it down! So every ah-choo is your body protecting you. Bless you!
6. Why Do We Have Fingerprints? Tiny Treads on Your Fingers!
Press a fingertip on a clean glass or mirror. What do you see? Breathe on it, and your print may show up! Wipe it away, and try another finger. Is it a loop, a whorl, or an arch? Your fingerprints help you grip and feel, and they're yours alone!
7. Why Do Scabs Form? Your Body's Build-a-Bandage Crew!
When a scab falls off by itself, look at the new skin, with a grown-up's okay. What do you notice about its color? Does it feel different from the skin around it? Draw it, or write about it, like a real scientist! So a scab isn't yucky. It's your body busy building you back!
Do this with a grown-up8. Why Do We Have Baby Teeth? A Starter Set for Your Smile!
Count in a mirror! Look at your teeth in a mirror. Count your baby teeth, or ask a grown-up to help. Notice their shapes. Some are flat for biting, and some are bumpy for chewing. What do you see? Be kind to your teeth today. They have a big job to do!
Do this with a grown-up9. Why Does Your Stomach Growl? The Rumbly Science!
Listen to your tummy! Before dinner, listen to your tummy. What do you hear? After dinner, listen again. What's different? Write down the sounds you hear: gurgles, rumbles, or quiet? Be curious, and be kind to your body. You're a scientist! So a growly tummy just means your hard-working muscles are squeezing away. Your body is amazing!
10. Why Do We Need Sleep? Your Secret Superpower!
Keep a sleep diary. For one week, write down when you go to bed, and when you wake up. Count how many hours you slept each night. Each morning, notice how you feel: happy, grumpy, or full of energy? Do you see a pattern? Good night, grow big, be bright!
11. Why Do We Yawn? The Big Stretchy Mystery!
Next time someone yawns, notice what your body does. Do you yawn too? Try reading about yawns. Did it make you yawn? I bet it did! Record it, and look for patterns! So the next time you yawn, remember: your body is pressing refresh!
12. Why Is Blood Red? The Iron and Oxygen Secret!
With a grown-up, look at the veins on your wrist. What do you notice? What color do they look? Why do you think they look blue? Here's a clue: skin changes how light bounces back to your eyes. So the blood is red, even though the veins look blue! So blood is red because of iron holding on to oxygen, delivering it everywhere you go!
Do this with a grown-up13. Why Do We Get Bruises? Purple, Green, Then Gone!
If you get a bruise, and a grown-up says it's okay, watch it change. Observe its color. Check it each day, at the same time. What do you notice? Draw the colors in order! So a bruise is just your body's repair crew, cleaning up after a bump!
Do this with a grown-up14. Why Do Your Ears Pop on a Plane or in a Car?
On your next hilly car ride, notice when your ears feel stuffy. Then swallow, or yawn. What happens? Why do you think that is? Record what you notice! So that pop is your body keeping things in balance, way up in the air, or down the road!
15. Why Can We Taste Sweet, Salty, Sour, Bitter and Umami?
With a grown-up, pinch your nose, and taste a jellybean. What do you notice? Now let go of your nose. What do you taste now? Your nose just switched the flavor back on! So your five tastes each have a job, guiding you to good food, and away from yucky stuff!
Do this with a grown-up16. Why Does Food Taste Weird When You Have a Cold?
Try this test to see the power of smell. First, sniff an orange slice, then taste it. Notice the flavor. Now pinch your nose closed, and taste it again. What changes? Without smell, flavor gets weaker. Record what you noticed! So a stuffy nose makes food taste weird. When it clears, flavor comes right back!
17. Why Does Your Funny Bone Tingle? (Spoiler: It's Not a Bone!)
Find the spot carefully. Do not hit it on purpose! Gently feel the back of your elbow, on the inside edge. Can you find the sensitive spot? Everyone's a little different! Be curious. Ask questions. Think like a scientist! So your funny bone isn't a bone at all. It's your ulnar nerve, saying hello!
18. Why Do We Blush? A Very Human Superpower!
Notice what happens next time your cheeks feel warm. What made you blush? How did your cheeks feel? What can you observe? You're a science detective! So blushing shows that your body cares about your feelings, and that's pretty cool!
19. Why Do We Have Earwax? Tiny Wax, Big Jobs!
Ask a grown-up: how do you clean the outer ear only? Here's a hint: a washcloth on the outside is all you need! Your ears handle the inside, all by themselves. Curious minds ask, and learn! So earwax isn't just yucky. It's your ears' own helper, trapping dust, and keeping them healthy!
Do this with a grown-up20. Why Do We Cry Tears? It's More Than Just Water!
Next time you yawn big, or watch a sad movie, notice your tears. Big yawns can squeeze your tear glands, and make your eyes water! What did you notice? Write it down, and be your own tear detective! So tears keep your eyes clean and healthy, and even help with big feelings. Smart eyes, smart tears!
21. Why Do We Need Water? Big Jobs for Tiny Cells!
Check your pee color, in private. It's a quick clue about your hydration! Pale, like lemonade? Good job! Dark, like apple juice? Time to drink more water. Water in. Energy up. Body strong. You've got this! So we need water because every part of you, from your blood to your brain, runs on it!
22. Why Do We Get Dizzy When We Spin? Wobbly Ear Fluid!
In an open, safe space, spin around twice, slowly, then stop. What do you notice about the room? Have a grown-up nearby, and sit down if you feel wobbly. Write or draw what happens! So you get dizzy because the fluid in your inner ear keeps swirling, even after you stop!
Do this with a grown-up23. Why Do We Get Fevers? Your Body's Smart Thermostat!
Can you remember a time you had a fever? How did your body feel? Hot, cold, or sleepy? Why do you think rest is so important? Draw or write down your ideas! So a fever is your body turning up the heat, to help beat the germs!
24. Why Do We Have Two Eyes? The Secret of Depth!
Hold two pencils a few centimeters apart. Close one eye, and try to touch the tips of the erasers together. Now open both eyes, and try again! What changes? Two eyes. Many advantages. Pretty clever! So two eyes team up with your brain, to give you depth, a wider view, and a handy backup!
25. Why Do Fingers Wrinkle in the Bath? Built-In Tire Treads!
Next time you're in the bath, compare a wet fingertip to your dry elbow. Which one wrinkled? Which one stayed smooth? Then try picking up a wet toy with wrinkly fingers. Is it easier? Science is all around you. Keep wondering and exploring! So wrinkly bath fingers aren't soggy at all. They're your nerves, helping you get a grip!
Expedition 2: Animals Who Share the Planet (25)
26. Why Can't You Tickle Yourself? Your Brain Saw It Coming!
Try this with a partner. First, tickle your own palm, with a certain pressure. Then have your partner tickle your palm with the same pressure. Which feels more tickly? Why do you think so? Be a scientist. Observe. Compare. Discover! So your brain is amazing! It tunes out what it expects, so it can notice what's new.
27. Why Do We Have Eyebrows? More Than Just Face Fuzz!
Stand in front of a mirror, and raise only your eyebrows. What happens to your face? Try different eyebrow moves, and see how your expression changes! Can a friend guess your feeling, just from your brows? So eyebrows keep sweat and rain out of your eyes, and help you share your feelings!
28. Why Do We Shiver? Your Muscles Make Heat!
Rub your palms together quickly, for 10 seconds. Now stop. Can you feel the warmth? You just made heat, with movement, just like shivering does! Your body knows just what to do, to keep you warm. So shivering is your muscles dancing to make heat. Your body is amazing!
29. Why Do We Sweat? Your Built-In Cooling System!
After running around, stand in a tiny breeze. What do you notice about how you feel? Why do you think that is? What's your hypothesis? That's a scientist's best guess! So sweat is your body's own air conditioner, keeping you cool when things heat up!
30. Why Do We Get Growing Pains? Achy Legs Explained!
After a running day, ask a grown-up to help you try a calf stretch. Face a wall, one foot back, heel down. Gently lean forward, and hold for 20 to 30 seconds. Then ask yourself: what did my legs do today? Did the stretch help? Keep moving, keep curious, and be kind to your amazing legs! So growing pains are just busy legs saying, we worked hard today!
Do this with a grown-up31. Why Do Cats Purr? The Rumble in the Voice Box!
If a friendly cat allows, rest two fingers gently on its throat while it purrs. What do you notice? Can you feel the rumble? Does the purr change when the cat breathes in, and out? Always be gentle, and let the cat decide! So a purr is a cat's rumbly voice box, saying I'm happy, or helping it feel calm and safe.
32. Why Do Bees Dance? The Waggle Dance Explained!
Try this outside! Point your arm toward a tree. Then point toward the Sun. But never look right at the Sun! How does the angle between them help you understand the bee's dance? You just thought like a honeybee! So bees dance to share directions, turning the hive into a buzzing map of flowers!
33. Why Don't Woodpeckers Get Headaches? A Built-In Helmet!
Tap gently on a table with your fingers. Now tap the same way on a folded towel. What feels different? The towel spreads out the tap, like soft padding spreads out a shock! But never bang your head, ever! Our brains aren't built like a woodpecker's. Draw or write your ideas, and be kind to your brain! So woodpeckers have clever heads, built just right for all that rat-a-tat-tat!
34. Why Do Dogs Tilt Their Heads? Clues From a Curious Pup!
With a friendly dog, say a new word, or make a funny sound. Watch the dog's ears and head. What do you notice? Does it tilt more for some words than others? Curious minds ask questions. Great observations find the answers! So a dog's head tilt may help it see your face, and hear you better. It's paying attention to you!
35. Why Are Flamingos Pink? It Starts With Their Dinner!
Compare colors and foods. Carrots have beta-carotene, an orange carotenoid. Shrimp are rich in astaxanthin, a pink-orange carotenoid. And flamingos turn these pigments into feather color! What pattern do you notice? Orange, pink, and more. They're all one color family! So flamingos are pink because of what they eat. Nature gives them their perfect rosy glow!
36. Why Do Chameleons Change Color? It's More Than Hiding!
Look at these three chameleons. What might each one be doing? Is the green one hiding? Is the orange one showing off? Is the dark red one on a sunny rock, warming up? What's your guess? Be curious, observe, and keep exploring! So chameleons change color to share feelings, stay warm, and blend in. Science is all around us!
37. Why Can Owls Turn Their Heads So Far?
Turn your head, only as far as is comfortable. Can you look behind you, without moving your body? What do you notice? How far can you turn, compared to an owl? Be curious. Observe. Discover! So owls turn their heads so far, thanks to tube-like eyes and extra neck bones. Science is everywhere!
38. Why Do Sharks Have So Many Teeth? A Conveyor Belt of Chompers!
Compare these two tooth shapes. The slicing tooth is sharp and triangle-shaped, like a steak knife, for cutting fish. The crusher tooth is flatter and rounded, like a nutcracker, for clams and crabs. What other animal teeth can you compare? Observe. Question. Discover! So sharks have so many teeth because they keep growing new ones. A shark's smile is always ready!
Do this with a grown-up39. Why Do Whales Sing? Songs That Travel for Miles!
With a grown-up, listen to a recording of whale sounds. What patterns do you hear? Do any sounds repeat? Why do you think the whales are singing? Science is everywhere, even deep in the ocean! So whales sing to find mates, stay in touch, and explore their ocean world. What a beautiful song!
Do this with a grown-up40. Why Do Penguins Huddle? Teamwork Keeps Them Warm!
Be a penguin family. First, stand alone in front of a fan. Feel the wind, and notice the cold. Next, stand beside your family. Notice the warmth, and share the heat! But don't squeeze! Be gentle, and give everyone space. Which felt warmer? Why do you think so? Penguins show us that teamwork keeps everyone warm. Science in action, together!
41. Why Is Spider Silk So Strong? Spiders' Super Thread!
Look at a garden web, but don't smash it. Find the straight spokes. They make the strong frame. Find the spiral that goes round and round. That's the sticky catching silk. Blow on it gently, and watch it stretch and bounce back. Then draw the web, and count its spokes! Spider silk is a tiny thread with a mighty secret: molecules that line up and lock together!
42. Why Do Butterfly Wings Have Colors? Paint vs. Tiny Mirrors!
Tilt a soap bubble or a DVD in the light. Watch the colors shift and shimmer as you move it. Now tilt a painted picture. Do its colors shimmer too? Why the difference? It's all about light and structure! Butterfly colors come from paint-like pigments, and from tiny scales that play with light. Be curious, observe kindly, and protect nature!
43. Why Do Camels Have Humps? It's Not What You Think!
Compare human fat and camel fat. Human fat is spread out, under the skin and around muscles and organs. Camel fat is stored in one tower-like hump. Try this: wrap one arm in a thick scarf, like a layer of fat. After a few minutes, which arm feels warmer? That's why camels keep fat in one place! A camel's hump is a fat backpack, not a water tank! Science is full of surprises. Keep wondering!
44. Why Do Cows Have Four Stomach Rooms? A Tiny Teamwork Tummy!
Watch a cow chewing when there's no grass in her mouth. You can visit a farm, or watch a video. Is she chewing cud? How long does she chew before she swallows? What patterns do you see? Cows and microbes work together, like a tiny teamwork tummy!
45. Why Can Snakes Swallow Big Prey? Jaws That Walk!
Look at a picture or a video of a snake opening its mouth. Notice how the lower jaw and stretchy skin work together. Watch the chin, where the two jaw halves spread apart. Then watch the jaws take turns walking forward. What else do you notice? Loose skull bones, split jaws, and walking jaws make snakes amazing swallowers!
46. Why Do Bats Use Sound to Hunt? Echoes in the Dark!
Clap your hands in a hallway. Can you hear the sound bounce back? Now try it outside, in an open space. Why is it different? Outside, there are fewer walls for the sound to bounce off! Echolocation helps bats hunt with precision, even when it's completely dark!
47. Why Do Octopuses Seem So Smart? Eight Clever Arms!
Watch closely. Can you spot the octopus hiding on the rocks? How does its skin match the color of the rocks? How does it match their bumpy texture? Why would hiding help an octopus? Big brains, clever arms, and super senses make octopuses seem so smart!
48. Why Do Fireflies Light Up? A Cold, Glowing Code!
Count a flash pattern on a summer night. Watch a firefly. Count the flashes and the pauses. Record the pattern in a notebook. Can you match it to a kind of firefly? And remember, always let fireflies go free! Fireflies glow with a cold chemical lamp, and talk in flashes! Science is everywhere. Keep wondering, keep exploring!
Do this with a grown-up49. Why Do Ants Follow a Trail? A Secret Scent Path!
Find an ant trail outdoors. Gently lay a leaf across the trail. But do not crush any ants! Watch what happens. Do the ants get confused? How do they find their way again? Ants follow a trail of scent, laid down by their sisters. That's teamwork, by smell!
50. Why Do Zebras Have Stripes? Scientists Are Still Asking!
Compare two zebra shoulder patterns. Pattern A has narrow stripes. Pattern B has wider stripes. Which pattern do you think would confuse flies more? Why? Here's a clue: some studies found narrower stripes work even better! Zebra stripes may be a clever fly shield, and scientists are still learning more! Keep observing, asking, and wondering!
Expedition 3: Earth, Weather, and Wild Places (25)
51. Why Is the Sky Blue? A Trick Light Plays in the Air!
Look up at the sky with the Sun behind you. Never look straight at the Sun! Where is the sky the deepest blue? Is it paler near the horizon? At sunset, what colors appear? What do you notice? The sky is blue because the air scatters blue sunlight all around us!
52. Why Do Volcanoes Erupt? Melted Rock Under Pressure!
Shake a bottle of soda with the cap on. Then imagine opening it outdoors, with a grown-up. The gas bubbles rush out and push the soda with them, just like gas pushes magma! Never shake soda at people. Science is fun and safe! Volcanoes erupt when gassy magma builds up pressure and finds a way out! Be curious, ask questions, and explore!
Do this with a grown-up53. Why Do Seasons Change? It's All About Earth's Tilt!
With a grown-up, shine a lamp on a tilted ball to model sunlight. Lean the top of the ball toward the lamp. Direct rays mean more heat. That's summer! Now lean it away. Indirect rays spread out, with less heat. That's winter. Walk the ball around the lamp, keeping the tilt the same. What changes? Seasons change because Earth is tilted as it travels around the Sun! Science is all around us. Keep wondering!
Do this with a grown-up54. Why Does It Rain? Follow the Water Cycle!
Try this with a grown-up. Heat some water in a pot, and cover it with a lid. After a while, look under the lid. Do you see droplets? Where did they come from? The steam cooled on the lid, just like vapor in a cloud! Rain happens when water rises, cools into clouds, and falls back down! Keep wondering, keep exploring, clever scientist!
Do this with a grown-up55. Why Does Thunder Follow Lightning? Light Wins the Race!
Next time you're indoors during a storm, count the seconds from the flash to the bang. Write it down. Divide by three to find the distance in kilometers. Count again. Is the storm getting closer, or moving away? Be safe. Be curious. Be a scientist! Thunder follows lightning because light is super fast, and sound takes its time! Keep asking, keep exploring!
56. Why Do Rainbows Appear? Light Bends and Splits!
Try this on a sunny day. Stand with your back to the sun. Spray a hose or spray bottle into the air in front of you. What do you see? Can you name every color? Keep your eyes open. Wonders are all around you! Rainbows appear when sunlight, water drops, and you are in just the right spots! Keep asking, keep exploring!
57. Why Do Earthquakes Happen? Slipping Slabs of Rock!
Grab two books. Push their spines together. Keep pushing, harder and harder, until one slips. What happens? Did they jump suddenly? That's just like rock slipping along a fault! Be curious, and keep exploring! Earthquakes happen when stuck plates finally slip, and send waves racing through the ground! Keep asking, keep exploring!
58. Why Do Tides Rise and Fall? The Moon's Big Pull!
Next time you're at a beach, look at the water. Note the waterline. Use a rock or a shell as a marker. Look again a few hours later. What changed? Did the water come in, or go out? Be curious, and keep exploring! Tides rise and fall because the Moon tugs on our oceans, as Earth spins around! Keep asking, keep exploring!
59. Why Do Rivers Flow to the Sea? Water Always Runs Downhill!
After it rains, go outside with a grown-up and watch a gutter. Look for tiny trickles. See how they join up and flow downhill? Where does the water go next? That's the same idea that sends rivers to the sea! Rivers flow to the sea because water always runs downhill, and the ocean is at the bottom! Keep asking, keep exploring!
Do this with a grown-up60. Why Do Mountains Exist? Three Ways to Build a Peak!
Lay a towel, or a soft cloth, flat on a table. Put your hands on both ends. Push them slowly toward each other. Watch it fold and rise! That's like colliding plates squeezing the land. Be curious, and keep exploring! Mountains exist because Earth's plates crumple, volcanoes pile up lava, and erosion shapes them! Keep asking, keep exploring!
61. Why Are Deserts So Dry? Three Big Reasons!
Find a desert next to mountains on a map. Look at both sides of the mountains. Which side is drier? Can you spot the rain shadow? Look for patterns. Think like a scientist! Deserts are so dry because rain gets blocked, sinking air stops clouds, or the ocean is too far away! Keep asking, keep exploring!
62. Why Do We Find Fossils? It Takes a Little Luck!
Grab a lump of play dough. Press a shell, or a leaf, into it. Lift it out gently. What kind of impression do you make? How might this be like the way fossils form? Keep wondering, keep exploring. Science is all around you! We find fossils when living things get buried fast, turn to stone, and the rock wears open! Keep asking, keep exploring!
63. Why Does Soil Matter? The Ground Is Full of Life!
Look at a spoonful of garden soil. What colors do you see? What textures? Is it gritty, smooth, or crumbly? What tiny living things might be there? Look for leaves, pebbles, and roots! Be curious, and keep exploring! Soil matters because it's alive, and it helps grow the plants and food we all need! Keep asking, keep exploring!
64. Why Do Caves Form? Rain, Rock and Slow Drips!
Remember: stalactites hold tight to the ceiling (they hang down), while stalagmites grow up from the ground!
65. Why Is Quicksand Not a Movie Deathtrap? Science Has the Story!
With a grown-up, mix one cup of cornstarch with half a cup of water. That's oobleck! Tap it. It feels solid! Now sink your finger in slowly. Poof! It turns soft. Quicksand also changes how it acts depending on how you move. Slow and gentle wins! Be curious, and keep exploring! Quicksand isn't a movie deathtrap, because you float! Stay calm, and move slowly. Keep asking, keep exploring!
Do this with a grown-up66. Why Do the Northern Lights Glow? A Sky Full of Color!
Look at an aurora forecast map. It shows where the northern lights are most likely to glow tonight.
67. Why Do Hurricanes Spin? Ocean Heat and Earth's Twist!
Stir a cup of water and watch it swirl. Now remember: a real hurricane is powered by heat from the ocean and twisted by Earth's turn!
68. Why Is Every Snowflake Different? One of a Kind!
Catch flakes on a cold, dark sleeve. What shapes do you see? Draw them!
69. Why Do Clouds Stay Up? They're Made of Tiny Drops!
Watch kettle steam. Boil water in a kettle, and see the steam rise. It cools and turns into tiny droplets, just like a cloud!
Do this with a grown-up70. Why Is Lightning So Hot? Big Energy in a Tiny Strike!
Notice how brief the flash is. From indoors, watch a storm through a window. How quick is that bright streak? What does that tell you about its power?
71. Why Do Canyons Get So Deep? Rivers, Rock and Rising Land!
Try this simple activity to see how water shapes the land: trickle water down a sand pile. What happens to the sand? How is this like a river carving a canyon?
72. Why Do Geysers Shoot? Nature's Underground Plumbing!
With a grown-up, watch a pot of water just before it boils. What do you notice about bubbles and steam?
Do this with a grown-up73. Why Does Compost Get Warm? Tiny Life, Big Heat!
Feel the outside of a scrap bin on a cool morning. What do you notice? Is the bin warmer than the air? Where is it warmest?
74. Why Do We Have Day and Night? Earth's Big Spin!
Try this: shine a lamp on a tilted ball (your Earth). Turn it slowly. Which side is lit? Which side is dark? That's day and night!
Do this with a grown-up75. Why Should We Care About This Planet? Small Choices Matter!
Name three jobs of one wild patch near you.
Expedition 4: Space and the Night Sky (25)
76. What If You Got Too Close to the Sun?
Compare a lamp close vs far on your hand. Close feels warmer. Far feels cooler. Never stare at the Sun.
Do this with a grown-up77. Is the Sun the Biggest Star? Sizes in Space!
Line up a pea, a marble, and a beach ball to understand the sizes of stars. The pea is like a red dwarf (tiny!), the marble is like the Sun (medium), and the beach ball is like a giant star (enormous!).
78. How Does the Sun Help Life on Earth?
Find one plant using the sun today! Where is it? What does it look like? What might it be using sunlight for?
79. Why Does the Moon Change Shape? Slices of Sunlit Moon!
Try this in a dark room: use a ball as the Moon and a lamp as the Sun. Walk around the ball and see how the lit shape changes!
Do this with a grown-up80. Why Do Stars Twinkle? Wiggly Air Between Us and Space!
Look up tonight and compare! First, look at a star. Does it twinkle? Then look at a bright planet. Is it steadier?
81. Why Is Space Black? A Big Question With a Bright Answer!
Imagine a flashlight in a dark room, first in clear air and then in dusty air. Light needs something to scatter to make a visible beam, just like in our sky!
82. Why Do We Orbit the Sun Instead of Falling In?
Swing a ball on a string in a circle above your head. Feel the pull in the string? That's like gravity! The ball's speed keeps it orbiting safely.
83. Why Do Astronauts Float? They're Falling Around Earth!
Imagine dropping an object in an elevator. If the elevator is falling at the same rate as the object, it seems to float! (Never try this in a real elevator!)
84. Why Do Eclipses Happen? Shadows in Space!
Try this! Hold a small coin in front of a lamp. What happens to the light behind it? The coin blocks the light, just like the Moon or Earth can block the Sun! Never stare at the Sun. Use safe solar eclipse glasses or watch with an adult.
Do this with a grown-up85. Why Is Mars Rusty Red? Iron, Oxygen and Dust!
Look at a rusty nail and a shiny one. What do you notice? What would happen if you left the shiny nail outside for a few days?
86. Why Does Saturn Have Rings? Ice, Rock and Gravity!
Stir glitter in a bowl of water and watch the pieces spin into a flat, swirling disk. That's kind of how Saturn's rings formed, with pieces spreading out and orbiting together!
87. Why Do Comets Grow Tails? A Dirty Snowball Meets the Sun!
With a grown-up, try this. Hold a hair dryer, on a cool setting, near a loose scarf. What happens to the scarf? The moving air pushes the fabric away, just like the solar wind pushes a comet's tail! Try it from different sides. Does the scarf always point away from the dryer? Comets grow tails when the Sun's heat and solar wind blow their ice and dust out into space. Keep wondering!
Do this with a grown-up88. Meteor or Meteorite? Learn the Space Rock Difference!
Watch a safe meteor shower with a grown-up. Find a dark, safe spot, away from bright lights. Let your eyes adjust, and look up after midnight. Be patient, and enjoy the show! Count how many meteors you see in ten minutes. Meteoroid in space, meteor in the air, meteorite on the ground. Keep looking up!
Do this with a grown-up89. Why Do We Draw Constellations? Stars, Stories and Maps!
Invent your own constellation. Draw five dots on a piece of paper, scattered any way you like. Connect them with lines. What does it look like? Give it a name, and make up a story about it! Then look for real star patterns on a clear night. Look up, connect the dots, and imagine. The sky is full of patterns, and full of your ideas!
90. Why Do We Have Leap Years? That Extra Quarter Day!
Try this math with a grown-up. Write zero point two five, four times. Now add them together. What do you get? One whole day! That's exactly why the extra day shows up every four years. So a leap year is a tiny math fix that keeps our seasons right where they belong!
Do this with a grown-up91. Why Do Telescopes Help? Seeing Far Into Space!
Roll a piece of paper into a tube. Look through it at something far away, like a tree or a sign. A paper tube has no lenses, so it can't gather extra light. But it blocks side light, and helps you focus on one spot. Real telescopes add lenses and mirrors to gather much more light. And never, ever look at the Sun through anything! Telescopes are super-powered light buckets. Keep exploring the universe!
92. Why Do Space Suits Look Puffy? A Wearable Atmosphere!
Try this with a grown-up. Blow a little air into a sealable plastic bag, and seal it. Watch the bag puff up! Now gently squeeze it. The air inside pushes out on the plastic, just like air inside a space suit! Try bending a finger inside a puffy glove too. Feel how stiff it is? A puffy space suit is a tiny bubble of Earth that astronauts wear. Science is all around you!
Do this with a grown-up93. Why Doesn't the Moon Fall Down? It's Falling Around Us!
Compare it to Earth orbiting the Sun. Earth is pulled by the Sun's gravity, but our fast sideways motion keeps us in orbit too. Same idea, huge scale! Now try this outside with a grown-up. Tie a soft ball to a string, and gently swing it in a circle. The string pulls in, like gravity. Let go, and the ball flies off sideways! What does that tell you about orbits?
Do this with a grown-up94. What Is Gravity in Kid Words? An Invisible Pull!
Jump up. What happens? You come back down! That's gravity pulling you back to Earth. Now drop a sock and a shoe at the same time, from the same height. Which lands first? They land at almost the same time! Gravity speeds up light and heavy things the same way. Gravity is the invisible pull that holds our whole world together. Look up and wonder more!
95. What Is a Light-Year? It's Distance, Not Time!
How long would a car take to drive one light-year? Say the car goes 100 kilometers per hour, without ever stopping. Time equals distance divided by speed. That's ninety-five billion hours! That's about ten point eight million years! Science helps us imagine the unimaginable. A light-year is a giant space ruler, made of light. Keep imagining big!
96. Why Do We Only See One Face of the Moon?
Put a chair in the middle of a room. Walk all the way around it, keeping your face pointed at the chair the whole time. Notice something? You turned around once, too! Now you're the Moon, and the chair is Earth. Your face stays pointed toward the chair, just like the Moon's face stays pointed toward Earth! Now try walking around facing the wall instead. What changes?
97. Why Does the Night Sky Change Through the Year?
Pick one star pattern, a constellation, and draw it. Write down the date and the time. Look again at the same time, one month later, and draw what you see. Has it moved? Is it higher, lower, or gone? You'll discover the sky's yearly change yourself! As Earth travels around the Sun, the night sky puts on a brand-new show. Keep looking up!
98. Why Don't the Planets Crash Into Each Other? Space Lanes!
Running tracks have lanes for a reason. Inner lanes are shorter. Outer lanes are longer. With friends, try walking around a track, or a circle drawn in chalk, each in your own lane. Stay in your lane, and nobody bumps! Planets do the same thing. And in space, the inner planets really do go faster too! Different lanes, different speeds, and lots of space. That's how planets share the solar system!
99. What Is a Black Hole? Without the Scary Movie Version!
Try it! Make a ramp with a book, and roll a ball up it. Now make the ramp steeper and steeper. At some point, the ball just can't make it to the top! That's a little like light trying to climb out of a black hole. Black holes aren't monsters. They're amazing places where gravity wins. Keep exploring!
100. Why Go to Space at All? Big Reasons, Little Planet!
Name one question that only space can answer. Is there life on Mars? What's inside Jupiter? Write your question down, and draw a picture of the spacecraft you'd send to find out. What tools would it need? Maybe one day, you'll be the one who finds the answer! We go to space to learn, to help life on Earth, and to follow our curiosity. Look up and wonder more!
Expedition 5: How Everyday Things Work (25)
101. Why Does Popcorn Pop? A Tiny Pressure Cooker!
Get an unpopped kernel and a popped one. Compare them side by side. The unpopped kernel is hard, small, and smooth. The popped one is light, big, and fluffy! Draw both, and list the differences. What do you think happened to the water inside? Popcorn pops because water inside the kernel turns to steam, and bursts the shell wide open. Pop, pop, hooray!
Do this with a grown-up102. Why Do Airplanes Fly? Lift, Thrust and Smart Wings!
Hold a strip of paper just under your lower lip, so it droops down. Then blow gently across the top. What happens? The paper rises up! Fast air over the top makes lower pressure, just like on a wing. Can you feel the lift? Airplanes fly because wings push air down, the air pushes back up with lift, and engines keep them zooming forward. Keep soaring!
103. Why Does Soap Clean Things? Tiny Molecules With Two Ends!
Ask a grown-up for two oily plates. Rinse one with water only. Rinse the other with water, plus one drop of soap. Which plate gets cleaner? Rub your finger on each one to feel the difference. That's soap at work! Soap cleans because one end grabs grease and the other end grabs water, so dirt rinses away. Scrub-a-dub-dub!
Do this with a grown-up104. Why Do Magnets Stick? North, South and Tiny Iron Bits!
Test a magnet on a spoon, a coin, and a pencil. First, make a prediction. Which ones will stick? Then try it, and notice what happens. Some spoons and coins stick, and some don't. It depends on the metal inside! Record your results! Magnets stick because opposite poles pull, and tiny bits inside iron line up and get pulled in. Stay attracted to science!
105. Why Is a Fridge Cold? It Moves Heat Out!
With a grown-up, find the coils behind or under your fridge. Carefully feel the air near them. Is it warm or cool? Now feel the air inside the fridge, and compare. That warm air is heat that came out of your food! Heat on the move! A fridge is cold because a special fluid carries heat out of the box, and dumps it out the back. Stay cool and curious!
Do this with a grown-up106. How Does a Light Bulb Work? Filaments vs. LEDs!
With a grown-up, find a lamp that's been on a while. Feel the lamp shade. Is it warm? Remember: NEVER touch the bulb itself. It can be very hot! Then try a lamp with an LED bulb. Which shade feels cooler? A warm shade means lots of energy became heat! A light bulb glows when electricity flows through a thin part that gets super hot, or through tiny LED chips. Keep shining bright!
Do this with a grown-up107. How Does a Touchscreen Know Your Finger?
On a grown-up's phone or tablet, tap with a knuckle. Then tap with a pencil eraser. Which one works? Why do you think so? Your knuckle is skin, so it works. The rubber eraser doesn't! What else could you test? A touchscreen knows your finger because your skin changes a faint electric field, and the phone maps the change. Keep tapping into science!
Do this with a grown-up108. Why Do Bikes Stay Up? The Science of Balance!
Roll a coin on its edge, across a smooth floor. Watch it stay up while it's rolling fast. What happens as it slows down? It wobbles, and falls over! Just like a bike, rolling helps it stay up. Bikes stay up because they're moving, and you make tiny steering moves to stay balanced. Keep on rolling!
109. Why Do Boats Float? The Secret of Buoyancy!
Drop a ball of clay into a bowl of water. It sinks! Now shape the same clay into a little bowl, and set it on the water. It floats! Why? The bowl shape pushes aside more water. How many pennies can your clay boat carry? Boats float because water pushes up, and a big hollow hull pushes aside enough water to hold the boat up. Stay afloat, explorers!
110. Why Does Rubber Stretch? Tangled Chains That Snap Back!
Stretch a rubber band slowly, then let it rest. Does it go back to the exact same size? Now stretch it many times. Does it change? Measure it with a ruler, before and after! Write down what you notice. Rubber stretches because its long tangled chains straighten when you pull, and snap back when you let go. Keep stretching your brain!
111. Why Does Metal Rust? Iron, Oxygen and Water!
With a grown-up, put one nail in a cup of water, and keep one nail dry. Check them every day, for a few days. Which one starts to rust first? Add a pinch of salt to another cup. Does that nail rust faster? Draw what you see each day! Metal rusts when iron meets oxygen and water, and they join to make flaky orange rust. Stay shiny and curious!
Do this with a grown-up112. Why Do Echoes Bounce? Sound Bounces Back Late!
Clap once in a tiled bathroom. Then clap once in a bedroom. What do you notice about the sound? Hard tiles bounce sound back, so the bathroom sounds echoey. Soft blankets soak it up! Which room is the best echo room? Echoes bounce because sound waves reflect off hard surfaces, and come back to your ears a little late. Hello, hello, curious kids!
113. How Do Clocks Keep Time? Ticks, Swings and Crystals!
Count sixty claps, at a steady beat. Then compare to a clock. Did your sixty claps take one minute? Were you too fast, or too slow? Can you clap as steadily as a pendulum? Write down your results. Clocks keep time by counting equal ticks, from swinging pendulums, or tiny vibrating crystals. Tick, tock, keep wondering!
114. How Does a Toilet Flush? The Science of the Siphon!
Flush the toilet, and stay to listen closely. First comes the big whoosh, then a gurgle when air sneaks in. Next you'll hear a hiss as the tank refills. Count how many seconds it takes! Ask a grown-up to lift the tank lid, so you can watch the float rise. Every flush is gravity and a siphon working together, with a tank that's always ready for next time!
Do this with a grown-up115. How Does a Zipper Work? Teeth, Tape and a Sneaky Slider!
Find a jacket or bag with a big zipper. Zip it very slowly, and watch the teeth lock together. Now unzip it slowly. Can you see the wedge splitting the teeth apart? Try closing it without the slider, just with your fingers. Is it hard? So a zipper is just rows of tiny teeth and one clever wedge, working together every time you zip!
116. How Does Velcro Stick? Tiny Hooks and Loops!
Look closely at a burr on a sock, or at a Velcro strip, with a magnifying glass. What do you notice? Can you spot the tiny hooks? Sketch what you see. Then try sticking the hook side to smooth paper. Does it grab? Why not? So Velcro is a clever idea borrowed from nature: tiny hooks and tiny loops, grabbing on together!
117. Why Do Glasses Help You See? Bending Light Just Right!
Fill a clear, round glass with water. Look through it at some words on a page. What do you notice? Do the words look bigger, or even flipped? The curved water bends light, just like a lens! So glasses help by adding just the right bend, so every picture lands in the perfect spot!
118. How Do Headphones Make Sound? Shaking Air Into Music!
Feel a speaker gently vibrate. With a grown-up, play music at low volume near a speaker. Place your fingertip very lightly on the speaker cone. Can you feel it move? What happens when you change the volume? So headphones are tiny shakers, turning electric patterns into moving air, and moving air into music!
Do this with a grown-up119. How Does Wi-Fi Work? Invisible Radio Waves!
Open a web page or video close to the Wi-Fi box. Then walk farther away, maybe into another room. Notice: does the page load slower? Do the signal bars drop? Distance and walls make the waves weaker! So Wi-Fi is really radio: invisible waves carrying codes of ones and zeros, right through the air!
120. How Does a Battery Work? Chemical Energy to Electricity!
With a grown-up, look inside a flashlight's battery holder. Trace the path: from the batteries, through the metal strips and the switch, to the bulb. Click the switch, and watch the loop close and the light turn on. And remember: never open a battery. The chemicals inside can be harmful. So a battery is stored chemical energy, turning into a flow of electrons whenever the loop is complete!
Do this with a grown-up121. Why Do Mirrors Flip Left and Right? Or Do They?
Write a word on paper, in big letters. Hold it up to a mirror. What do you see? Now try writing a word backward, so it reads the right way in the mirror! Which letters look the same in a mirror? Try A, H, O, and T! So mirrors don't swap left and right at all. They flip front to back, and our brains do the rest!
122. Why Do Balloons Stick to Your Hair? Static Electricity!
Rub a balloon on a wool sweater, or on your hair. Hold it against a wall, and gently let go. Does it stick? Count how long it stays up! Try again on a rainy day. Does it stick as long? So balloons stick because of static electricity: tiny charges jumping, and opposites pulling together!
123. Why Does a Straw Work? It's Not Really Sucking!
Pinch the top of your straw shut, and try to drink. What happens? Now dip a straw into water, and cover the top with your finger. Lift it out. The water stays inside the straw! Air pushing up from below holds it there. Lift your finger, and splash! So every time you sip through a straw, remember: the air around you is giving your drink a big push!
124. Why Do Bubbles Pop? A Thin Skin of Water!
Blow one bubble, and watch how long it lasts. Count the seconds until it pops. Watch the colors swirl. Do they change right before it pops? Then wet your finger. Can you touch a bubble without popping it? So a bubble is a thin, stretchy skin of soapy water. When it gets too thin: pop!
125. Why Does Glue Stick? A Handshake at the Surface!
Compare tape on clean paper and dusty paper. Stick a piece of tape on clean paper, and press it down. Sprinkle a little flour on another paper, and stick tape on that. Now peel them both. Which one holds better? Why do you think that happened? So glue flows in, grabs on, and dries into a strong bridge, holding things together!
Expedition 6: Food, Kitchen, and Tiny Science (25)
126. Why Does Bread Rise? Meet the Tiny Yeast Helpers!
With a grown-up, mix warm water, a spoonful of sugar, and some yeast in a cup. Wait about ten minutes, and watch for foam. Bubbles and foam mean the yeast is alive, and making gas! Try it again with cold water. What changes? So bread rises because tiny yeast munch sugar, and blow bubbles into stretchy dough!
Do this with a grown-up127. Why Does Ice Float? Water's Roomy Crystals!
Drop an ice cube and a small rock into a glass of water. Which one floats? Which one sinks? Look closely: how much of the ice cube sticks up above the water? Most of it stays under, just like an iceberg! So ice floats because freezing water spreads out into roomy crystals, and that keeps lakes cozy for fish!
128. Why Do Apples Turn Brown? A Chemical Suntan!
With a grown-up's help, cut two apple slices. Leave one slice plain. Brush lemon juice on the other. Wait fifteen minutes, then check. Which one is browner? Try other ideas too, like plain water or salty water! So apples turn brown when oxygen, an enzyme, and apple compounds team up, and a squeeze of lemon slows them down!
Do this with a grown-up129. Why Does Salt Melt Ice? Getting in the Way of Freezing!
Put two ice cubes into two bowls. Sprinkle salt on one ice cube, and leave the other plain. Watch and compare every few minutes. What do you notice? Which one melts faster, and where? So salt melts ice by getting in the way of freezing, and turning ice into salty slush!
130. Boiling or Simmering? What's the Difference?
With a grown-up, watch a pot of water heat up on the stove. First, tiny bubbles cling to the bottom. Those are bits of air. Next comes a gentle simmer, and then a big rolling boil! Stay back from the hot pot, and let your grown-up do the cooking. So simmering is gentle and calm, boiling is hot and rolling, and now you can tell them apart!
Do this with a grown-up131. Why Do Eggs Get Hard When Cooked? Proteins on the Move!
With a grown-up, compare a fried egg white to a raw one. Look at the color. Is it clear, or white? Gently tilt each one. Is it runny, or firm? But never eat raw egg for the test. Just look! So eggs get hard because heat unfolds their protein chains, and tangles them into a firm, tasty net!
Do this with a grown-up132. Why Does Chocolate Melt in Your Hand? Cocoa Butter Science!
Try this simple test. Hold one chocolate square in a cool spoon, and another in your palm. Wait two minutes. Which one melts first? Your warm hand wins! Then, with a grown-up's okay, you can eat your experiment! So chocolate melts in your hand because cocoa butter melts just below body temperature. Yum!
Do this with a grown-up133. Yeast or Baking Powder? What Makes Dough Rise?
Look at a recipe, and find which lifter it uses. Is it yeast, baking powder, or maybe baking soda? Then check how long it needs to rise or rest. Lots of waiting? That's probably yeast at work! So, yeast is alive and slow, baking powder is a fast chemical mix, and both make bubbles that lift our food!
134. Why Does Spicy Food Feel Hot? Meet Capsaicin!
With a grown-up, take a tiny taste of something spicy. Sip some water. Does the heat go away? Then try sipping some milk. Which one cools your mouth better? And remember, always try new tastes safely, with a grown-up! So spicy food feels hot because capsaicin tricks your tongue's heat sensors, and your brain reads it as heat!
Do this with a grown-up135. Why Do Leftovers Go Bad? Meet the Tiny Microbes!
After dinner, help put the leftovers away fast, with a grown-up. Cover them, label them with the date, and pop them in the fridge. Then check: how many days until they should be eaten? So leftovers go bad because tiny microbes grow in warm, wet food, and the cold fridge slows them down!
Do this with a grown-up136. Why Does a Metal Spoon Get Hot? Heat on the Move!
With a grown-up, put a metal spoon and a wooden spoon in a mug of warm water, or warm soup. Wait one minute. Then carefully touch each handle. Which one feels warmer? The metal one! So a metal spoon gets hot because metal passes heat energy along fast, all the way up to the handle!
Do this with a grown-up137. Why Do Cold Glasses Get Wet? The Water Comes From the Air!
Put a cold glass of ice water on the counter, next to a glass of room temperature water. Watch the outside of both glasses. Which one gets wet? Only the cold one! So cold glasses get wet because the chilly glass turns water vapor from the air into droplets. That's condensation!
138. Microwave or Oven? How Do They Heat Food Differently?
Which tool would you pick for a crispy cookie, versus last night's soup? The cookie needs dry heat to turn golden, so pick the oven. The soup is full of water, so the microwave warms it fast! So an oven heats the air around your food, and a microwave wiggles the water inside it. Each one has its best job!
Do this with a grown-up139. Why Does Toast Turn Brown? The Maillard Reaction!
With a grown-up, toast one slice light, and one slice a bit darker. Smell them both. Then take a taste. Which one smells stronger? The darker toast has more new flavor molecules! So toast turns brown because heat makes sugars and proteins team up in the Maillard reaction. Yum!
Do this with a grown-up140. Why Does Water Boil at 100°C? Molecules Break Free!
With a grown-up, watch a pot of water heat up on the stove. First you'll see tiny bubbles, then big rolling bubbles, and steam rising. But remember: never lean over the pot. Steam is very hot! So water boils at one hundred degrees Celsius because that's when its molecules have enough energy to escape as steam!
Do this with a grown-up141. Why Does Sugar Dissolve? Water Molecules Pull It Apart!
Fill one cup with cold water, and one with warm water. Stir the same spoonful of sugar into each. What do you notice? Which one dissolves faster? So sugar dissolves because water molecules surround it and pull it apart, and stirring and heat make it go faster!
142. Why Does Milk Go Sour? Tiny Microbes Make Acid!
With a grown-up, check the date on a milk carton. Then give it a careful sniff. Does it smell fresh, or sour? And remember: never drink spoiled milk! So milk goes sour because bacteria eat its sugar and make acid, which makes it sour and lumpy!
Do this with a grown-up143. Why Does Oil Float on Water? Density in a Jar!
Put water and a little oil in a jar, and close the lid tight. Shake it hard, then set it down, and watch them split. Now add a drop of dish soap, and shake again. What changes? So oil floats on water because the two don't mix, and oil is less dense, so it rides right on top!
144. Why Do Cookies Spread in the Oven? Butter, Bubbles and Heat!
Look for a cookie recipe that chills the dough first. With a grown-up, bake some cookies from chilled dough, and some from warm dough. Which ones spread more? Measure them with a ruler! So cookies spread because butter melts and bubbles puff, until the heat sets the edges and locks in the shape!
Do this with a grown-up145. Why Does Pasta Get Soft? Starch Swells in Hot Water!
With a grown-up, cook some pasta. Have your grown-up scoop out one noodle at five minutes, and another at twelve minutes. Let them cool. Take a bite of each. How are they different? So pasta gets soft because hot water soaks in, and the starch swells up and turns the noodle tender!
Do this with a grown-up146. Why Does Baking Soda Fizz? A Base Meets an Acid!
With a grown-up, put a pinch of baking soda in a cup. Then add a little splash of vinegar. Listen and watch. What happens? Try adding more vinegar. Does it fizz again? So baking soda fizzes because it's a base, and when it meets an acid like vinegar, they make carbon dioxide bubbles!
Do this with a grown-up147. Why Does Ice Cream Melt? Frozen Water, Fat and Air!
Put a scoop of ice cream in a bowl, on the table. Start a timer, and check it every few minutes. How long does the scoop last? Try one in the sun, and one in the shade! So ice cream melts because warm air gives its molecules energy, and the frozen mix turns slushy, then soup!
148. Why Does Honey Last So Long? A Sticky Science Secret!
Put a drop of honey and a drop of juice on a plate, and leave them out. Check them every day, with a grown-up. Which one grows fuzzy mold first? But remember: do not taste the old juice! So honey lasts so long because it's very low in water and acidic, so most microbes cannot grow there!
Do this with a grown-up149. Why Does Steam Burn More Than Water? Hidden Heat!
With a grown-up, watch steam rise from a kettle or pot, from a safe distance. Look closely, just above the spout. Can you see a clear gap before the white cloud? That clear part is invisible steam! Look, but never touch. So steam burns more than water because it carries extra hidden heat, and dumps it all when it turns back into water!
Do this with a grown-up150. Why Do We Cook Food at All? Three Big Reasons!
Name one food that is safer after heat. How about eggs, or chicken? Now name a food that's yummy raw, like an apple! Write your answers on a list, and share them at dinner! So we cook food to make it safer, easier to chew and digest, and full of delicious new flavors!
Do this with a grown-up