Book 6 activities
Try it at home: 150 science activities from Book 6
Every question in A Million Whys Book 6, The Ocean Expedition, ends with a "Think like a scientist" idea. Here they are in one place. Each one links to its question page, with the video and the full answer.
Questions 1 to 25 (25)
1. Why Is the Ocean Salty?
Stir a spoonful of salt into warm water, with a grown-up. Pour a little into a saucer and set it in a sunny spot. Wait a few days and watch the water disappear. What is left behind, and why? A scientist always wonders and tests. Happy exploring!
Do this with a grown-up2. Why Are There Waves?
Fill a pan with water and float a cork or a small toy on it. Blow gently across the surface. Watch the toy. Does it race ahead, or bob? Why do bigger winds make bigger waves? Scientists test things many times to be sure. Try it again!
3. Why Do Tides Go in and Out?
Visit a beach with a grown-up at the edge of the water. Push a stick into the sand right at the water's edge. Wait 30 minutes. Where is the water now, and why? Scientists check their results over and over. Happy exploring!
Do this with a grown-up4. Why Is the Ocean Blue?
Look at a clear glass of water. Is it blue? With a grown-up, look into a swimming pool. Compare the shallow end with the deep end. What could turn a bay green? Scientists look closely and compare. Happy exploring!
Do this with a grown-up5. Why Does the Shore Keep Changing?
Pile some sand in a baking tray. Tilt the tray and pour water gently over the pile. Watch where the sand goes. What would happen if the waves stopped? Scientists ask questions and test them. Happy exploring!
6. Why Does Foam Show Up on Waves?
Fill a bowl with plain water. Blow out gently through a straw, and watch the bubbles. Now add one drop of dish soap, and try again. Why do the bubbles last longer? Scientists test, observe, and compare. Happy exploring!
7. Why Can the Water Pull You Out?
Pile sand across a tray, but leave one narrow gap. Pour water behind the sand wall. Watch where the water escapes. Who should pick the swim spot? A grown-up and a lifeguard! Safety comes first, and scientists always stay safe. Happy exploring!
Do this with a grown-up8. Why Do Tide Pools Appear?
At low tide, find a pool with a grown-up. Count the animals you see, without touching them. Draw one animal in your notebook. What must an animal do to wait in a shrinking pool? Scientists watch quietly and gently. Happy exploring!
Do this with a grown-up9. Why Is Some Sand Wet Under the Dry Top?
Fill a clear cup with dry sand. Pour water in slowly, and watch. Can you see the water fill the gaps? Why does the top of a beach dry first? Scientists look closely and keep records. Happy exploring!
10. Why Is Beach Sand Often Tiny?
With a grown-up, put a few pieces of chalk in a jar with water. Close the lid tight and shake for a minute. Look at the water and the pieces. Why are river stones often smooth too? Scientists test ideas by trying them out. Happy exploring!
Do this with a grown-up11. Why Do Seashells Wash Up?
With a grown-up, find some empty shells. Sort them by shape and size. Draw your favorite one. What job did the shell do when it was a house? Scientists treat living things kindly. Happy exploring!
Do this with a grown-up12. Why Does Seaweed Pile on the Beach?
Find a seaweed line with a grown-up. Look closely for tiny hopping animals, without touching. Notice whether the pile is a line or a lump. Who eats the rotting plants? Scientists look carefully and stay safe. Happy exploring!
Do this with a grown-up13. Why Does the Ocean Smell Like That?
Next time you visit the sea, take a slow breath. Notice where the smell is strongest. Compare it on a calm day and a stormy day. What is riding in those droplets? Scientists use their senses to learn. Happy exploring!
14. Why Do Some Beaches Have Pebbles?
Look at a few pebbles with a grown-up. Compare their shapes. Which are the roundest? Imagine what a storm could do to them. What would years of extra grinding do? Scientists compare and measure. Happy exploring!
Do this with a grown-up15. Why Do Waves Get Bigger Near Shore?
Watch the waves from a safe spot. Count the seconds between waves. Watch how each wave changes as it nears the sand. Why does the wave slow when the water gets shallow? Scientists watch carefully and stay safe. Happy exploring!
16. Why Is There a Line of Junk on the Sand?
Walk along the line with a grown-up. Sort what you see into natural and human-made. Note how far up the beach the line is. What does a bottle in the line tell you? Scientists keep notes about what they find. Happy exploring!
Do this with a grown-up17. Why Is Some Sand Black?
Look at different kinds of sand with a grown-up. Hold a magnet close, but not touching, to the sand. See which grains jump to the magnet. What rock was nearby that made this sand? Scientists test with tools like magnets. Happy exploring!
Do this with a grown-up18. Why Does Wet Sand Hold a Castle?
Try making a tower from dry sand. Add water a spoonful at a time. Find the amount that works best. Why does dripping water ruin a wall? Scientists change one thing at a time. Happy exploring!
19. Why Do Footprints Fill with Water?
With a grown-up, walk on wet sand. Make a footprint and watch it closely. Then make another one up on dry sand. Where did the water in the print come from? Scientists compare dry and wet places. Happy exploring!
Do this with a grown-up20. Why Does Salt Help You Float?
With a grown-up, fill two glasses with water. Stir salt into one of them. Gently lower an egg into each one. Would you float higher in a salty sea or a lake? Scientists test with experiments. Happy exploring!
Do this with a grown-up21. Why Is the Ocean Colder than a Puddle?
Fill a shallow pan and a deep bucket with the same water. Set both in the sun for an hour. With a grown-up, feel the water in each one. Why does a kiddie pool warm up faster than a bay? Scientists measure temperatures carefully. Happy exploring!
Do this with a grown-up22. Why Do Rocks Get Holes By the Sea?
Rub a piece of soft chalk with sand on a sidewalk. Look at what happens to the chalk. Try a hard stone, too. Why do some rocks get holes faster than others? Scientists notice differences and ask why. Happy exploring!
23. Why Does Spray Feel Colder than the Air?
With a grown-up, wet one finger. Blow gently on your wet finger. Compare it with a dry finger. Why does wind make wet skin feel colder? Scientists compare what they feel. Happy exploring!
Do this with a grown-up24. Why Is the Horizon a Straight Line?
Look at a ball and imagine being as small as an ant. Put a sticker on the ball and look at it up close. Does your patch look flat? Why would a higher dune show a farther ship? Scientists use models to explain big things. Happy exploring!
25. Why Do Birds Follow the Tide Line?
Watch the birds from a distance with a grown-up. Draw where the tide line is. Check again in an hour and see where the birds are. Why is the wet stripe richer than dry sand? Scientists watch quietly and take notes. Happy exploring!
Do this with a grown-upQuestions 26 to 50 (25)
26. Why Do Fish Have Gills?
Look at a picture of a fish with a grown-up. Find the gill cover behind its eye. Watch a fish in an aquarium and see its gill covers open and close. Why would still water be harder than moving water? Scientists watch closely and stay kind to animals. Happy exploring!
Do this with a grown-up27. Why Don't Fish Drown?
Look at a fish in an aquarium with a grown-up. Watch its gill covers open and close. See how the bubbler moves the water. What is the fish missing if the water stops moving? Scientists look closely and care for animals. Happy exploring!
Do this with a grown-up28. Why Do Fish Have Scales?
Look at a picture of roof shingles. Overlap paper cards like shingles and tilt them. Pour a little water on top, and see where it goes. What story might the rings tell? Scientists look for patterns. Happy exploring!
29. Why Do Some Fish Swim in Schools?
Watch fish in an aquarium with a grown-up. Can you find a leader? Watch how quickly they turn together. Why might the middle of the school be safer? Scientists look carefully and care for animals. Happy exploring!
Do this with a grown-up30. Why Are Fish Slippery?
Wet your hands and feel a bar of soap. Compare that with dry hands. Which one slides more? Why would a dry towel be a problem for a fish? Scientists treat animals gently. Happy exploring!
31. Why Can Some Fish Glow?
In a dark room, hold up a glow stick. Wave it around and see how bright it looks. Now try it in sunlight. Who is the light for? Scientists compare lights in bright and dark places. Happy exploring!
32. Why Is a Flounder So Flat?
Look at a picture of a flounder with a grown-up. Find the two eyes. Draw a baby flounder and an adult. What job does flatness do? Scientists compare young and grown-up animals. Happy exploring!
Do this with a grown-up33. Why Does a Seahorse Look Like a Horse?
Look at a picture of a seahorse. Draw how its tail curls. Curl a piece of string around a pencil. Why would a gripping tail beat a fast tail here? Scientists look closely at what animals use their bodies for. Happy exploring!
34. Why Does an Octopus Have Three Hearts?
Watch an octopus video with a grown-up. Draw three hearts on an octopus. Count its 8 arms. Why might gills need their own pumps? Scientists ask careful questions. Happy exploring!
Do this with a grown-up35. Why Can an Octopus Change Color?
Look at the rocks or leaves around you. Pick a spot where an octopus could hide. Draw the colors it would need. What two jobs can color do? Scientists observe quietly. Happy exploring!
36. Why Do Crabs Walk Sideways?
Try walking sideways, with your knees out. Now walk forward the same way. Which was easier? What does the shell face while it runs? Scientists make careful notes. Happy exploring!
37. Why Does a Hermit Crab Wear a Shell?
Look at empty shells on the beach. Compare their sizes. Which would fit a bigger crab? Why does the crab need a used shell, instead of growing its own armor? Scientists are kind to animals and homes. Happy exploring!
38. Why Does a Starfish Have Five Arms?
Look at a picture of a sea star. Count its arms. Find where its mouth would be. Why might five directions beat two? Scientists look closely at tiny details. Happy exploring!
39. Why Can a Starfish Grow an Arm Back?
At a tide pool with a grown-up, look gently. Never touch or pull a sea star. Count its arms. Can you spot a short one still growing? Why would growing an arm be worth the energy? And what must stay in one piece for the rebuild to work?
Do this with a grown-up40. Why Do Jellyfish Sting?
Visit an aquarium with a grown-up. Look closely, but never touch. Draw the bell and the tentacles. Then ask: why would a soft animal need a dart? And why can a jelly on the sand still sting?
Do this with a grown-up41. Why Isn't a Jellyfish a Fish?
Look up pictures of a fish and a jellyfish. List the parts a fish has. Which of those does a jelly have? What three fish parts is a jelly missing? And why do scientists care about body plans?
42. Why Do Some Clams Make Pearls?
Find an empty shell with a shiny inside, like a mussel or oyster shell. Look closely at its smooth coat. Draw the shiny layers you see. Then ask: why is a smooth coat helpful when grit slips in?
43. Why Do Some Fish Have Whiskers?
Close your eyes, and have a friend hand you a safe, hidden object. Feel it with just your fingertips. Can you guess what it is? Now think: why would taste on a whisker beat eyes in muddy water?
44. Why Do Flying Fish Jump?
Fold a paper glider with wide wings. Launch it, and measure how far it glides. Then try bigger wings, and launch it again. Now think: why is the air a good escape room when the hunter is a fish? And what job do the extra-long fins do?
45. Why Does an Eel Look Like a Snake?
Look at photos of an eel and a snake. Draw each one's body. Which one shows gills? Then think: why would a tube body help in a reef crack? And what two fish parts show an eel is not a snake?
46. Why Does a Pufferfish Puff Up?
Blow up a balloon, and measure it before and after. That is how much a puffer can grow! Watch a video of a puffer instead of catching one. Why would getting big and spiky beat swimming away? And what is the fish swallowing?
47. Why Do Some Fish Live in the Dark?
Dim a room, and use a flashlight. What can you see? What can you not see? Try a glow-in-the-dark toy. Why would a huge eye help at the edge of light? And what job can glow do that eyes cannot?
48. Why Doesn't an Anemone Sting a Clownfish?
Slip a glove over your hand, and think about how it protects you. A coat can be a barrier. Now ask: what would happen if the slime coat washed off? And why would a host want a guest?
49. Why Do Shrimp Dart Backward?
Fill a tub with water, and hold a flat paddle or a spoon. Push the water hard in one direction. Which way does the water go, and which way do you feel pushed? Why is going backward a better surprise than forward? And which part is the engine?
50. Why Do Barnacles Stick So Hard?
Visit a shore with a grown-up, and look for barnacles. Look closely, but never scrape. Sketch the little volcano shape. Why glue the head instead of walking? And what are the kicking feathers for?
Do this with a grown-upQuestions 51 to 75 (25)
51. Why Do Whales Breathe Air?
Hold a normal breath for a few seconds, only as long as is comfortable. A whale can hold its breath for many minutes! Do not push yourself, just notice. Why would a nose on top beat a nose on the face? And what is the whale missing that a fish has?
52. Why Do Whales Have a Blowhole?
Watch a video of a whale at the surface. Spot where the blow comes out. Think of a lid on a cup that keeps water out. Why is a rooftop nose handy in waves? And why does the flap need to seal tight?
53. Why Do Some Whales Sing?
Make a can telephone with two cans and a string. Pull the string tight, and talk across the room. A tight string carries sound well, a bit like water. Why might water be a better telephone than air? And what could a changing song mean?
54. Why Do Whales Travel So Far?
Find a map of a whale migration route. Trace the path from the pantry to the nursery. Add up how far it is. Why split the pantry and the nursery? And what does the calf still need to grow?
55. Why Is a Blue Whale So Huge?
Float a toy in a tub of water, then lift it out. Does it feel heavier in the air? Water holds things up, and that helps a whale be big. Why can the ocean hold a bigger body than land? And what food makes giant size possible?
56. Why Do Some Whales Have Baleen Instead of Teeth?
Mix some rice into a bowl of water. Pour it through a strainer. What stays behind, and where does the water go? Why would a comb beat teeth for catching krill?
57. Why Do Dolphins Click?
Stand a few steps from a big wall, and clap once. Listen for the echo. Now step farther back. How does the echo change? Why would sound beat eyes in murky water? And what is the melon for?
58. Why Do Dolphins Ride a Boat's Wave?
Fill a tub or a big sink with water. Push a spoon slowly through, and watch the bulge it makes. That is a tiny bow wave! Why is a moving slope cheaper than swimming hard? And what happens if the boat stops?
59. Why Do Sharks Have So Many Teeth?
Look at photos of shark teeth in a book or a museum. Draw a front tooth, with rows of spares behind it. What is the job of a sharp triangle? And why are spare teeth better than one set for life?
Do this with a grown-up60. Why Do Many Sharks Keep Swimming?
Look up two kinds of sharks, like a nurse shark and a great white. Which one can rest on the bottom? Which one cruises in open water? Why would a shark that pumps water live near the bottom? And what does a cruiser need that a rester does not?
61. Why Do Some Sharks Look Like Carpets?
Draw a rocky, sandy floor. Now color a shark in the same blotchy pattern, and hide it. Can a friend spot it? Why would waiting beat chasing on a reef? And what job do the tassels do?
62. Why Is a Great White Pale Underneath?
Draw a fish on paper, and color it dark on top and pale underneath. Hold it up and look at it from the side. Does its shape look flatter and fainter? Now ask: why would a white belly fool a fish looking up? And what would a dark belly do instead?
63. Why Don't Most Sharks Hunt People?
List the animals that sharks usually eat. Draw a seal's shape, then a swimmer's shape. Why is a seal silhouette more convincing than a person on a dock? And what two clues tell a shark that a meal is the wrong food?
64. Why Does a Hammerhead Have a Hammer?
Hold a ruler across your forehead, and picture an eye at each end. That is a wide view! Now sweep a magnet over a table, and imagine sensing hidden things. Why put eyes at the ends of a bar? And what can electricity sensing do that eyes cannot?
65. Why Can a Shark Smell a Tiny Bit of Blood?
Put a drop of food coloring in a clear glass of water. Watch how it spreads out. Where is the color strongest? That is how a shark follows a trail! Why follow the stronger side? And what other senses could confirm the smell?
66. Why Is a Ray So Flat?
Cut a flat shape from paper, with two wide wings. Glide it across the room. Look at ray photos too. Why would eyes on top beat eyes on the belly? And what job does flatness do?
Do this with a grown-up67. Why Does a Manta Look Like It Is Flying?
Next time you wash your hands, move your hand quickly through water. Now wave it in the air. Which feels stronger? Water pushes back much more, and that is how a manta swims. Why can a slow flap move a wide body in water?
68. Why Is a Whale Shark Not a Whale?
Name two traits that prove an animal is a fish. Name two traits that prove an animal is a mammal. Now sort a shark, a whale, and a dolphin into the right group. What traits proved each one?
69. Why Do Orcas Hunt Together?
Pick a chore, like tidying a room. Time one person doing it alone, then time a team sharing the jobs. Teamwork wins! Why would a family recipe beat hunting alone? And what can a grandmother remember that a calf cannot?
70. Why Do Seals Climb Onto Rocks?
If you visit a seal beach with a grown-up, watch from far away. Use binoculars if you have them. Count the seals on the rocks. Why leave the pantry to rest on a rock? And what two jobs does dry land do?
Do this with a grown-up71. Why Do Sea Turtles Come Back to a Beach?
Think about a path you know well, like the walk home. What clues help you remember it? Turtles use clues too. Why would the birth beach be a good address later? And what can a bright streetlight do to a hatchling?
72. Why Is a Giant Squid So Hard to See?
Turn off the lights in a room with a grown-up. Wait a minute, and notice how your eyes adjust. Then switch the light on. Bright, right? Why would huge eyes help in faint light? And why would a camera light be a problem?
Do this with a grown-up73. Why Do Whales Have Blubber?
With a grown-up, fill a bowl with ice water. Coat one finger in a thick layer of shortening, and put both fingers in. Which finger feels warmer? Why would fat beat fur in the ocean? And what three jobs is blubber doing?
Do this with a grown-up74. Why Do Whales Leap Out of the Water?
Drop a ball into a big tub or sink of water. Listen to the splash, and watch the ripples spread. A big splash sends a big signal! Why would a splash be a good message? And what else might a leap knock off the skin?
75. Why Is a Manatee Called a Sea Cow?
Imagine eating nothing but salad all day. A manatee does it, and it eats a lot! Think about the warm, shallow water. Why would a plant-eater stay in warm shallows? And what nickname hides the elephant cousin fact?
Questions 76 to 100 (25)
76. Why Is Coral an Animal, Not a Rock?
Look at close-up photos of coral in a book or an aquarium. Can you spot the tiny polyps? Draw one polyp and its limestone cup. Why would a soft animal make a hard cup? And what is the rock really made of?
77. Why Do Corals Need Sunlight?
Let's think about sunlight. Why do reefs love clear, shallow water? Plants on land need sunlight too. Can you find one growing by a sunny window? What does the coral give the algae in return? And remember, never blast a reef with bright lights for fun.
78. Why Do Reefs Look Like Cities?
Let's think about homes. Why would a wrinkly reef have more neighbors than a smooth wall? What is a hole for, besides hiding? Try crumpling some paper, and see how many tiny toy animals can hide in it. Count how many hiding spots you can find!
79. Why Do Corals Bleach?
Let's think about hungry corals. Why would losing its roommates make a coral hungry? Dip a thumb in warm water, then cool water. Which one would be more stressful to live in all the time? What would help the color return? Hint: think about cooler water and less pollution.
80. Why Can't You Stand on Coral?
Let's think about slow growth. Why does slow growth make one step so costly? What is the rock-like reef covered with? If you ever visit a reef, float, keep your fins up, and let a grown-up pick the swim spot. Draw a picture of a kind reef visitor.
Do this with a grown-up81. Why Is a Kelp Forest So Tall?
Let's think about tall kelp. Why does kelp race to the surface? What does a holdfast do instead of roots? Why might cold currents feed these forests? Think of a plant on land. How is it different from kelp?
82. Why Does Kelp Have Floats?
Let's think about floats. Why lift the blades instead of the holdfast? What do you think is inside the float? Hold an air-filled balloon underwater. Which way does it want to go? If you visit a beach with a grown-up, look at washed-up kelp, but leave living kelp alone.
Do this with a grown-up83. Why Do Otters Help Kelp?
Let's think about forest helpers. Why would eating urchins help a forest grow? What do you think happens if the otters disappear? Draw an arrow from kelp to urchin, and from urchin to otter. Remember, wild animals need space. A selfie is not worth a bite!
84. Why Is Plankton So Important?
Let's think about tiny cooks. Why does a food web start with tiny specks? What would a cloudy week do to the plant plankton? With a grown-up, look at a drop of pond water through a magnifier. Draw a food chain that ends with a whale.
Do this with a grown-up85. Why Does the Sea Sometimes Glow at Night?
Let's think about glow. Why would plankton flash when they get bumped? Why is the glow often blue-green? On a dark night, ask a grown-up to take you to watch real water. Never pour chemicals into water to fake a glow.
Do this with a grown-up86. Why Do Some Algae Make the Water Green?
Let's think about green water. Why would fertilizer washing into the sea feed a bloom? What color would the water be with fewer specks? Stir a drop of green food coloring into a glass of water. More drops mean what? Remember, green is not always safe soup. Check signs before a dip.
87. Why Do Sponges Have Holes?
Let's think about holes. Why does a sponge pump water instead of chasing food? What job do tiny holes do that one big mouth could not? Soak a kitchen sponge, and look at its holes. How are they like a real sponge? Remember, a wild sponge is a living animal. Look, don't grab.
88. Why Do Anemones Look Like Flowers?
Let's think about flowers that hunt. Why would looking like a flower help a hunter? What job do the tentacles do? Draw a flower and an anemone side by side. How are they different? Remember, look but do not touch.
89. Why Do Parrotfish Poop Sand?
Let's think about sand. Why does a parrotfish swallow rock to get algae? Where does the new sand go? With a grown-up, look at sand through a magnifier. What do you see? Remember, never feed wild fish.
Do this with a grown-up90. Why Do Cleaner Fish Pick at Bigger Fish?
Let's think about teamwork. Why would a big fish hold still for a tiny nibble? What does each partner get out of the deal? Can you think of other animals that help each other out? Remember, watch wild cleaner fish from a distance.
91. Why Do Mangroves Grow in Salt Water?
Let's think about roots. Why do some roots poke up into the air? What two jobs do the tangled roots do? Stir salt into water, and taste a tiny drop with a grown-up. Could a normal plant drink this? Remember, stay on marked paths.
Do this with a grown-up92. Why Are Seagrass Beds Called Nurseries?
Let's think about nurseries. Why is a maze safer than open sand? What two jobs does seagrass do besides hiding babies? Play hide and seek in tall grass, then in an open field. Where is it easier to hide? Remember, leave the seagrass where it grows.
93. Why Do Some Reefs Grow in Rings?
Let's think about rings. Why does the coral keep growing up as the land sinks? What sits in the middle of the ring? Think of a donut. The hole is a lagoon, and the ring is the reef. Remember, reefs are living, so we only look.
94. Why Is a Lagoon Calmer than the Open Sea?
Let's think about waves. Why does a wall of coral steal wave energy? What would the lagoon do if the reef broke? Make waves in a bathtub. Then put a wall in the water. What changes? Remember, ask a grown-up before swimming anywhere.
Do this with a grown-up95. Why Do Some Snails Have Bright Colors on a Reef?
Let's think about colors. When might bright colors help hide a snail? And when might they work as a warning instead? Draw a snail with a camouflage pattern, and another with a warning pattern. Remember, look but do not pocket live shells.
96. Why Do Christmas-Tree Worms Vanish?
Let's think about hiding. Why does the worm hide its gills first? What clue says danger is coming? Wave your hand over a friend's head, gently. Do they notice the shadow? Remember, poking does not help science.
97. Why Do Some Corals Come Out at Night?
Let's think about night. Why hunt at night when the algae already feed you? What is different about night water? If you ever watch a night reef, why would a dim light help? Remember, night animals sting, so look but don't touch.
98. Why Is the Water Around a Reef So Clear?
Let's think about light. Why would dirt hurt a sunny partnership? What two things help keep reef water clear? Stir some soil into a glass of water. Shine a flashlight through it. What do you see? Help keep the water clean by picking up litter with a grown-up.
Do this with a grown-up99. Why Do Scientists Plant Coral?
Let's think about gardens. Why start with a fragment instead of a seed? What else must stay healthy for the planting to work? Ask a grown-up to help you grow a plant from a cutting. How is it like coral gardening? Remember, never break wild coral.
Do this with a grown-up100. Why Does a Tiny Change in Heat Hurt a Whole Reef?
Let's think about heat. Why would one degree matter more to a reef than to the deep ocean? Who else feels it after the coral fades? How quickly does an ice cube melt in warm water compared with cool water? Remember, small choices add up, with grown-ups to help.
Do this with a grown-upQuestions 101 to 125 (25)
101. Why Do Ships Float?
Let's think about floating. Why does a steel bowl float when a marble sinks? What happens if the bowl fills with water? With a grown-up, shape foil into a boat and see how many pennies it can hold. Always wear a life jacket on a boat.
Do this with a grown-up102. Why Is a Keel on the Bottom of a Boat?
Let's think about balance. Why put weight at the bottom, not the top? What two jobs is the keel doing? Try floating a cork with a coin taped low on it. Does it stay upright? Always wear a life jacket on a boat.
103. Why Do Big Ships Have Such Small-Looking Propellers?
Let's think about pushing water. Why push a lot of water slowly? What would a tiny airplane-style propeller do on a huge tanker? Use your hand like a paddle to push water backward in a bathtub. Which way do you move? Always keep clear of the water near boats.
104. Why Does a Lighthouse Flash?
Let's think about signals. Why blink instead of staying on? What two clues tell you which lighthouse it is? With a flashlight and a friend, invent a code of long and short flashes. Can your friend guess your code?
105. Why Did Sailors Use Stars to Find Their Way?
Let's think about stars. Why does a higher Pole Star mean you are farther north? What do sailors lose on a cloudy night? With a grown-up, try to find the North Star on a clear night. Stargaze safely, on land.
Do this with a grown-up106. Why Is a Compass Needle Twitchy on a Ship?
Let's think about compasses. Why would a wooden boat bother a needle less? What extra tool ignores magnetism? With a grown-up, hold a magnet near a compass. What does the needle do? Remember, leave real ship instruments alone.
Do this with a grown-up107. Why Are There Lines on a Nautical Chart?
Let's think about charts. Why draw lines that connect equal depths? What could go wrong if a wreck symbol is missing? Draw contour lines around a sandcastle, one line for each level. Look at a real chart with a grown-up, and find one depth number.
Do this with a grown-up108. Why Do We Use Latitude and Longitude?
Let's think about grids. Why do you need two numbers, not just one? What happens to the longitude lines at the poles? Find your home on a globe, with a grown-up. Which way is north? Pick a city, and see if you can find its latitude and longitude.
Do this with a grown-up109. Why Is the International Date Line in the Pacific?
Let's think about days. Why not draw the line through a big city? What problem does a zigzag solve? Find the Pacific Ocean on a globe, and trace the Date Line. Ask a grown-up what day it is in a country far away.
Do this with a grown-up110. Why Does a Submarine Go Up and Down?
Let's think about floating. Why does a submarine change its weight instead of flapping wings? What two things can the tank switch between? With a grown-up, fill a bottle partly with water in a tub. Does it float or sink? Remember, keep water play safe, with a grown-up nearby.
Do this with a grown-up111. Why Do Submarines Make So Little Wake on the Surface?
Let's think about waves. Why does the line between air and water make waves? What would a shallow sub do to the surface? Drag a toy boat through water. Then try dragging it deeper. What changes? Remember, subs are not toys.
112. Why Do Scientists Use Sonar?
Let's think about echoes. Why use sound instead of a spotlight? What two things can the echo tell you? With a grown-up, try shouting in a big, empty hall. How long is the echo? Which animals use echoes to find their way?
Do this with a grown-up113. Why Is the Seafloor Mapped in Strips?
Let's think about strips. Why overlap the ribbons? What is missing in the unmapped holes? Draw a lawn on paper, and color it in stripes, with each stripe overlapping a little. Look at a seafloor map with a grown-up, and find an underwater mountain.
Do this with a grown-up114. Why Do Research Ships Drag Nets and Bottles?
Why sample more than one depth? With a grown-up, fill two clear jars, one with tap water and one with pond water. Hold them up to the light and compare them. What would a surface bucket miss?
Do this with a grown-up115. Why Is a Weather Buoy Left Alone in the Ocean?
Why leave a machine out there instead of a ship? Then, what two jobs does the radio do? Try this: with a grown-up, check a weather map and see where the buoys are.
Do this with a grown-up116. Why Do Satellites Watch the Sea From Space?
Why is it useful to see the whole basin at once? What could a color map tell you about tiny plants? With a grown-up, look at a public satellite map of the sea.
Do this with a grown-up117. Why Is There a Dead Zone in Some Coastal Water?
Why does a feast become a shortage? What season do you think makes a dead zone grow? Try this: with a grown-up, look up a map of a dead zone.
Do this with a grown-up118. Why Do Currents Move Like Rivers in the Sea?
Why isn't the whole ocean one still bathtub? What three forces steer a current? With a grown-up, blow gently across a bowl of water and watch the surface move.
Do this with a grown-up119. Why Is the Gulf Stream Famous?
Why would warm water change the air above it? What two things squeeze the current along the coast? With a grown-up, find the Gulf Stream on an ocean map.
Do this with a grown-up120. Why Do Containers Stack So High on a Ship?
Why lock the corners instead of using rope only? What could happen if the heavy boxes sit too high? With a grown-up, stack small boxes and see which way is steadier, heavy on the bottom or on top.
Do this with a grown-up121. Why Do Harbors Need Pilots?
Why isn't a good GPS enough? What two kinds of knowledge are being combined? With a grown-up, look at a harbor map and find the channel.
Do this with a grown-up122. Why Do Some Boats Have Two Hulls?
Why can two thin hulls beat one fat one? What does width do that weight also does? With a grown-up, float a small tray and a pair of bottles joined by a stick, and nudge them to see which is steadier.
Do this with a grown-up123. Why Does a Life Jacket Work?
Why does foam beat a soaked sweater? What extra job does a collar do? With a grown-up, drop a piece of foam and a wet sock in a basin, and see which one floats.
Do this with a grown-up124. Why Do Divers Need Tanks?
Why compress the air? What would happen if you held your breath all the way up? With a grown-up, squeeze an empty bottle and imagine packing in more air.
Do this with a grown-up125. Why Is the Deep Ocean So Hard to Visit?
Why is pressure the biggest wall? What two jobs can a robot do that a person can't do for long? With a grown-up, watch a live deep-sea dive and spot the lights.
Do this with a grown-upQuestions 126 to 150 (25)
126. Why Do Hurricanes Grow Over Warm Ocean Water?
Why does the heat have to come from the sea? What two things can starve the engine? With a grown-up, look up a hurricane map and find the warm water.
Do this with a grown-up127. Why Does a Storm Surge Flood a Coast?
Why is a surge different from river flooding? What two extras make the pile taller? With a grown-up, check whether your area has an evacuation map.
Do this with a grown-up128. Why Do Sea Walls Sometimes Make Beaches Worse?
Where does the wave energy go if the sand can't move? What softer shield could take a hit? With a grown-up, push a wave in a tray with sand, first with a block wall and then without it.
Do this with a grown-up129. Why Do Wetlands Protect Towns From Storms?
Why does friction matter in a flood? What two jobs do roots do? With a grown-up, pour water across a tray with, then without, a patch of sponge or grass.
Do this with a grown-up130. Why Is Plastic in the Ocean a Problem?
Why don't tiny bits count as gone? What two harms can one bag cause? With a grown-up, count the single-use plastic items you use in a day.
Do this with a grown-up131. Why Do Helpers Cut Six-Pack Rings?
Why does growing make a loop worse? What is the difference between scrap and a trap? With a grown-up, find a safe loop of paper and think about how an open one differs from a closed one.
Do this with a grown-up132. Why Do Sea Turtles Eat Bags?
Why does motion matter as much as color? What two changes on land could stop this trick? With a grown-up, count how many plastic bags your family uses in a week.
Do this with a grown-up133. Why Is Oil in Water So Hard to Clean?
Why doesn't oil just sink and vanish? What two tools slow the spread? With a grown-up, pour a little cooking oil into a bowl of water and watch what it does.
Do this with a grown-up134. Why Do Beaches Need a Cleanup Day?
Why count what you pick up? What two places does beach trash start? With a grown-up, join a safe cleanup, or sort and count the trash in a recycling bin.
Do this with a grown-up135. Why Do Some Sunscreens Hurt Reefs?
Why would a tiny dose still matter on a stressed reef? What two swaps lower the dose? With a grown-up, check a sunscreen label and talk about which kind to pick.
Do this with a grown-up136. Why Do We Measure the Ocean's Temperature?
Why isn't one number enough? What two tools can measure heat far from shore? With a grown-up, check a pool or bath temperature at the same time every day for a week.
Do this with a grown-up137. Why Is Sea Level Rising?
Why doesn't floating sea ice raise the level much when it melts? What two sources do raise it? With a grown-up, mark the water level on a glass with ice cubes, and watch it as they melt.
Do this with a grown-up138. Why Do Ice Sheets Matter to a Beach Far Away?
Why is the phrase on land the key? How can one island change a beach an ocean away? With a grown-up, rest some ice cubes on a plate above a bowl of water, mark the level, and let them melt into it.
Do this with a grown-up139. Why Does Extra Carbon Dioxide Change Seawater?
Why would a tiny pH change bother a shell? What two places share the extra CO2? With a grown-up, blow through a straw into water with a bit of cabbage juice, and watch for a color change.
Do this with a grown-up140. Why Do Scientists Tag Fish and Turtles?
Why follow one animal instead of only counting a crowd? What two questions can a track answer? With a grown-up, find a tagged-turtle tracking map online and follow one trip.
Do this with a grown-up141. Why Is a Marine Park a Kind of Fence?
Why would rest grow more fish, not fewer? What two things does a boundary protect? With a grown-up, find a marine park on a map and see what its rules are.
Do this with a grown-up142. Why Do Fishers Use Limits and Seasons?
Why protect the spawning week? What happens if every big breeder is taken? With a grown-up, look up the fishing rules in your area and spot a limit and a season.
Do this with a grown-up143. Why Should You Put a Shell Back If a Creature Is Inside?
Why is an empty shell still useful on the beach? What two clues say still home? With a grown-up, look at shells in a tide pool or photo, and count the clues of life.
Do this with a grown-up144. Why Is Dumping Aquarium Fish in the Sea a Bad Idea?
Why might a pretty fish win too well? What two better endings exist for an unwanted pet? With a grown-up, look up a local aquarium club that rehomes pets.
Do this with a grown-up145. Why Do Ships Have Rules About Ballast Water?
Why is a tiny hitchhiker enough to change a lake? What two rules shrink the risk? With a grown-up, look up where the nearest big port is and what ships come to it.
Do this with a grown-up146. Why Do Some Coasts Restore Dunes?
Why do roots beat a concrete wall for a beach? What two jobs does a fence do? With a grown-up, build a small sand pile in a tray, blow on it gently, and see how a barrier changes where the sand lands.
Do this with a grown-up147. Why Should a Tide-Pool Visit Be Look, Don't Poke?
Why does flipping a rock matter? What two things does a pool animal already fight? With a grown-up, watch a tide pool for five minutes and count what you notice without touching.
Do this with a grown-up148. Why Does Turning Off Extra Lights Help Hatchling Turtles?
Why is the sea usually the bright side? What two light habits on land help? With a grown-up, check which lights in your home shine outdoors at night.
Do this with a grown-up149. Why Do Kids' Small Habits Still Matter for the Ocean?
Why does tiny stop being tiny at a million times? Name two land habits that help the waves. With a grown-up, pick one small habit to try for a week.
Do this with a grown-up150. Why Is the Ocean Worth a Whole Expedition?
Which page made you want another trip? What is one habit you will take to the next beach? Write down your next question, and go find an answer. A library and a grown-up can help.
Do this with a grown-up