Book 5 activities
Try it at home: 150 science activities from Book 5
Every question in A Million Whys Book 5, The Time 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.
Expedition 1: Dinosaurs and Giants (25)
1. Giant Dinos! Why Were Some Dinosaurs So Huge?
Let's guess like scientists. Pretend you can measure one giant leg bone. How could you guess the dinosaur's height from just that one bone? Why does a small head work on a big body? And what job did being huge do? Reaching, warmth, or safety? Discuss it with a friend!
2. Tiny Arms, Huge Bite! Why Did T. Rex Have Tiny Arms?
If the head does the hunting, what job is left for the arms? Try this. Hold your arms straight out in front of you and lean forward. What happens to your balance? Compare arm size to body size, not to your own arms. And what evidence would settle the argument?
3. Fluffy Fossils! Why Do We Think Dinosaurs Had Feathers?
Step two: scientists look close. With microscopes and scanners, they can see tiny pigment sacs in some feather fossils. Those sacs hint at what color the feathers might have been. But color is still a scientist's best guess.
4. Reach for the Sky! Why Long Necks on Some Dinosaurs?
What does a small head save on a long neck? Try holding a heavy book close to your chest, then far out in front of you. Which is harder? Why add bones, instead of stretching 7 bones forever? And how would you test an idea about reaching high leaves?
5. Plates on Its Back? Why Did Stegosaurus Have Them?
If the plates were only armor, why would they be so thin? What second job could a tall row of plates do? Which clue is stronger, the grooves in the bone, or a scene from a movie? Think about it, then explain your idea to a friend!
6. Horns and a Frill! Why Did Triceratops Have Both?
If you only found the skull, what job would you guess first? What second job could the frill also do? How could scars on the bone help you decide? Talk it over with a friend, and remember that good guesses use clues!
7. Pocket-Sized Dinos! Why Were Some Dinosaurs So Small?
Name one job a small dinosaur could do that a giant could not. Draw a small dinosaur next to a giant and a kid, and label who is who. What clue would prove a fossil is an adult, not a baby? And why do you think films skip the small ones?
Do this with a grown-up8. Egg-cellent Question! Why Did Dinosaurs Lay Eggs?
Why is a shell a useful little room? What clue would show that a parent stayed with its nest? Which living animals still lay eggs like this? Think about a bird, a turtle, or a lizard. Draw an egg and label the shell, the yolk, and the pores.
9. Stomp Stomp! Why Do We Find Dinosaur Footprints?
If two different print sizes walk side by side, what might that mean? What can a track tell you that a bone cannot? Why is a line of prints better than just one print? Next time you walk on soft ground, look back at your own tracks!
10. Dino Crowds! Why Did Some Dinosaurs Live in Herds?
What two clues would make a herd idea stronger? Why might a flood fool you into thinking animals lived together? What job does the middle of the group do? Try to think of a living animal that travels in a herd.
11. Chomp! Why Did Meat-Eating Dinosaurs Have Sharp Teeth?
If you found only one tooth, what diet would you guess? What second clue would make you more sure? Why would a plant-eater need a different shape of tooth? Look at your own teeth in a mirror. Which ones are sharp for cutting, and which are flat for grinding? Tell a friend what you notice.
Do this with a grown-up12. Munch Munch! Why Did Plant-Eaters Have Beaks or Grinders?
Why would a leaf need grinding, but meat need slicing? What would worn-flat teeth tell you? How could a beak and a set of grinding teeth work as a team? Try it with a snack. Bite a carrot, then chew it. What did each part do?
13. Wings Over Dinos! Why Did Flying Reptiles Soar?
What job did the long finger do? Why might we find fewer wing fossils than foot fossils? How is a pterosaur different from a bird? Think about wings, feathers, and skin. Try making a paper glider. Which folds help it soar?
14. Sea Monsters? Why Were There Giant Sea Reptiles Too?
What clue says swimmer instead of walker? Why must an air-breathing hunter come up to the surface? How can old seafloor sit in a dry hill now? Hint: land can slowly lift up, and seas can move over millions of years.
15. Hungry Giants! Why Did Dinosaurs Need So Much Food?
If the forest thinned, who would feel it first, a tiny dinosaur or a giant? What job does a long gut do? Why is bigger not always better? Draw a food pile for a giant and one for a chicken-sized dinosaur. Compare them!
16. Oops, Wrong Colors? Why Do Movies Get Dinosaurs Wrong?
What part of a dinosaur is least likely to keep its color? What tiny clue can still hint at a pattern? Why is the sentence we do not know yet a good scientific sentence? Try drawing a dinosaur, and mark which colors are known and which are guesses.
17. Cool Crests! Why Did Some Dinosaurs Have Crests and Sails?
If a crest is hollow, what job becomes more likely? What second job could a sail still do? How would you test a honk idea without a living dinosaur? Try humming through a long cardboard tube. What changes about the sound?
18. Fast or Slow? Why Do Scientists Argue About T. Rex Speed?
Which measurement would change the speed guess the most? Why can two honest answers exist at the same time? What new fossil would settle part of the argument? Try measuring your own leg and your friend's leg. Who might take longer steps?
19. Not Mini Adults! Why Were Baby Dinosaurs Different?
If two skulls look different, what else should you check before naming two species? What job might a baby have that an adult does not? How can a growth ring help? Compare your baby photos with a photo of you now. How have your proportions changed?
Do this with a grown-up20. Worldwide Dinos! Why Did Dinosaurs Live Almost Everywhere?
Why does a changing map help a group of animals spread? What would a fossil in Antarctica tell you about the weather long ago? Why is the group of dinosaurs not the same as one kind, like T. Rex? Find a world map, and see how the continents could fit together like puzzle pieces.
21. Cluck Cluck! Why Is a Chicken a Clue About Dinosaurs?
Which chicken part looks like a dinosaur leftover? What could a feathered fossil add to the chicken clue? Why is a relative not the same as a clone? Draw a family tree with a chicken on one branch.
22. So Many Dinos! Why Did So Many Kinds Exist?
Why does a long stretch of time help make more kinds? Why could T. Rex and Stegosaurus never share a picnic? What job might armor do that speed does not? Draw your own dinosaur, and give it a job.
23. No Fresh Dino Meat? Here's Why We Never Find It!
Which part of a body lasts the longest? Why does burial help a fossil form? What movie idea fails first when you add real time? Read a museum sign, and find how old the fossil is.
24. The Big Goodbye! Why Did Non-Bird Dinosaurs Disappear?
Why do plants suffer first when the sky gets dark? Why might a tiny bird last when a giant cannot? What worldwide clue is still sitting in the rock? Go outside, and count how many birds you can spot.
Do this with a grown-up25. Be a Dino Detective! How Do We Think Like One?
Pick one dinosaur question from this whole expedition. What clue would make your answer stronger? What rule keeps the clue safe for the next kid? Start your own notebook with a clue, a question, and a picture.
Expedition 2: Fossils and Clues (25)
26. Bone to Stone! Why Does a Bone Turn Into a Fossil?
What has to happen before minerals can move in? Why do most bones never become fossils? Did the animal's skin color survive if the bone's color changed? Make a bone shape out of clay, and press it into sand to see the imprint.
27. Layer Cake Earth! Why Are Fossils Found in Rock Layers?
If two fossils are in different layers, which one is probably older? What could scramble the page order? Why is the layer part of the clue, not just the bone? Stack colored paper or clay layers, then hide a toy bone inside.
28. Dig Detectives! Why Use Brushes Instead of Shovels?
What clue would a shovel destroy first? Why do we bag the dirt instead of dumping it? Why does the grid matter as much as the bone? Try brushing sand off a toy, using a soft paintbrush.
29. Cast for a Bone! Why Make a Plaster Jacket?
What does the jacket protect besides the bone? Why put the label on the outside? What would a bumpy truck ride do to an unwrapped fossil? Wrap a toy bone in paper towels and tape, then give it a gentle shake test.
Do this with a grown-up30. Missing Pieces! Why Are Most Fossils Not Whole Skeletons?
Why do teeth show up more often than skin? What might have moved bones far apart? Why is a partial find still useful? Draw a dinosaur with some missing parts, and guess what the parts could be.
31. Squished Fossils? Why Do Some Look Smashed or Stretched?
If a fossil is flat, what should you check besides the animal? Why compare it with an undistorted bone of the same kind? What story does the folded rock add? Press a lump of clay flat, and see how its shape changes.
32. Tooth Talk! How Can a Tooth Tell What an Animal Ate?
What would flat, worn teeth suggest? What second clue would make a meat-diet guess stronger? Why is likely better than proved forever? Look at your own teeth in a mirror. Which are sharp, and which are flat?
Do this with a grown-up33. Leaf Prints! Why Do We Find Fossils of Leaves and Wood?
What can a leaf fossil tell you that a tooth cannot? Why do the veins matter? If you find stone wood and a long-neck bone together, what idea gets stronger? Find a leaf outside, and look at its veins with a magnifying glass.
Do this with a grown-up34. Time Capsule in Gold! Why Is Amber So Special?
What does amber save that a flat leaf print cannot? Why is a trapped bug still not a dinosaur clone kit? How could bubbles inside amber be a clue? Look at a drop of sticky tree sap outside, from a distance, and draw what you see.
Do this with a grown-up35. Leave It There! Why Not Pocket a Fossil From a Park?
What information vanishes when a fossil leaves its rock? Who else loses if you take it? What can you collect instead of the bone? Take a photo and draw a fossil picture in your notebook, and leave the real fossil alone.
36. Copycat Bones! Why Do Museums Use Casts?
Why keep the original bone at all? What does the label show you? Why would two museums share one shape? Press a coin into clay, and pour in plaster or wax to make a tiny cast with a grown-up.
Do this with a grown-up37. Follow the River! Why Do Old River Maps Help Fossil Hunters?
Why might river sand hold bones? Why does a map help before you start walking? What rules keep you and the land safe? Draw a map of your neighborhood with a river or a path on it.
38. Fossil Travelers! Why the Same Fossil on Two Continents?
What two clues make the split idea stronger? Why would a desert fossil match a faraway forest fossil's cousin? Look at a world map, and see which coasts look like puzzle pieces. Draw the continents on paper, and cut them out to fit together.
Do this with a grown-up39. Snap and Label! Why Number and Photograph Every Find?
Try this with a grown-up. Set out five small things, like shells or pebbles, on a tray. Take a photo. Then put a numbered sticky note beside each one. Now mix them up, and use your photo to put them back. What would disappear if you skipped the photo?
Do this with a grown-up40. Yes, Really! Why Can Coprolites Be Useful?
Play detective. Imagine a coprolite with fish scales and bone chips inside. What did the animal eat? Now imagine a tooth. What can dung tell you that a tooth cannot? And why is the place where it was found still part of the clue?
41. Follow the Trail! Why Do Trackways Count as Fossils?
Make a trackway. Press your hand or foot into playdough or damp sand. Walk across it once, then take a big leap, and compare your strides. What can a line of prints tell you that one bone cannot?
42. Save Some for Later! Why Leave a Dig Site Half-Buried?
Ask why waiting is sometimes the scientific move. Imagine the team has no plaster and a storm is coming. What should they do? Now imagine a better tool will exist in ten years. Should they wait? And how would you keep a hidden spot from getting lost? Patience is a science skill, too!
43. Sparkly Stone! Why Do Some Fossils Sparkle or Change Color?
Try growing crystals with a grown-up. Stir salt into very warm water until no more will dissolve. Hang a string in the jar and wait a few days. Then look with a magnifier. If a crystal sparkles, did the animal sparkle? What mineral clue is that?
Do this with a grown-up44. Rock Clock Clues! Why Is Index Fossil a Useful Nickname?
Play the date-stamp game. Imagine a stamp used for one week only, and another used for a whole year. Which one tells you the date more exactly? So why would a long-lived species make a worse clock?
45. Tiny Tools! Why Do Labs Use Tiny Saws and Needles?
Try a gentle dig with a grown-up. Hide a small toy in a lump of playdough, or in a cookie. Use a toothpick and a soft brush to slowly free it. Why is slow still science? And why glue before you lift?
Do this with a grown-up46. X-Ray Vision! Why Do CT Scans Help With Fossils?
Try slicing with a grown-up. Ask a grown-up to cut a banana into thin slices. Look at each slice, and try to imagine the whole banana. How is that like a CT scan?
Do this with a grown-up47. Number One Fossil! Why Is a Holotype Extra Important?
Pick a holotype. Choose one of your toys, like a favorite dinosaur. Give it a name tag, and put it in a labeled box. Why is it useful to have just one special example?
48. Name Change! Why Do Dinosaur Names Sometimes Change?
Play the name game. Imagine you found a new animal, and gave it a name. Later, you find a bone that shows it was two animals. Would you change the name? What evidence would you want?
49. Still Digging! Why Do We Find New Fossils Every Year?
Go on a fossil safari. With a grown-up, walk along a path, a beach, or a rocky wall. Look for shapes in the stones, like shells or leaf prints. Take photos, but leave everything where it is.
Do this with a grown-up50. Fossil Detective Mode! How Do We Think Like One?
Be a detective at home. Pick one mystery object, like a rock, a shell, or a leaf. Notice it, measure it, and draw it in a notebook. What do you know? And what do you not know yet?
Expedition 3: Ice, Fire, and Changing Earth (25)
51. Ice Sculptors! Why Does Ice Carve Valleys?
Make a tiny glacier with a grown-up. Freeze a paper cup of water with a few small pebbles in it. Then push the ice block across damp sand, or clay. What do you notice? Why do valleys have steep sides?
Do this with a grown-up52. Scratch Marks! Why Do Glaciers Scratch the Rock?
Make your own scratches with a grown-up. Drag a small pebble across a bar of soap, in one direction. Look at the lines it leaves. Which way do they point? What clues do scratches on a rock give you?
Do this with a grown-up53. Ice Age Leftovers! Why Are Some Lakes Left by Ice?
How do we know a lake is glacial? Look for a bowl shape, with a valley around it. Look for scratched rocks and piles of stones at the edge. What clue would you look for first?
54. Mountain Maker! Why Does a Volcano Make a Mountain?
Build a mountain with a grown-up. Slowly pour dry sand through a funnel onto a tray. Watch a cone grow, layer by layer. What job does gas do? And why does a volcano need a weak spot?
Do this with a grown-up55. Hot Rock Mix-Up! Why Is Lava Different From Magma?
Try this with a grown-up. Watch the bubbles rise in a fizzy drink in a clear cup. Then compare warm honey and cold honey. Which one flows faster? How is that like lava cooling down?
Do this with a grown-up56. Boom or Ooze? Why Do Some Volcanoes Explode?
Try it with a grown-up. Compare pouring cold honey and warm honey. Which one traps a bubble better? Which honey is like sticky magma?
Do this with a grown-up57. Friend and Foe! Why Is Volcanic Ash Dangerous and Useful?
Try this with a grown-up. Look closely at some sand with a magnifying glass. Feel a pinch of soil, and compare the two. What do plants find in soil that they can't get from sand?
Do this with a grown-up58. Steamy Surprise! Why Do Hot Springs and Geysers Exist?
Try this with a grown-up. Watch a kettle boil, from a safe distance. Notice the steam rising from the spout. What is the boiler in nature? And why do boardwalks matter?
Do this with a grown-up59. Shake, Rattle and Roll! Why Does Earth Have Earthquakes?
Try this with a grown-up. Hold a thin ruler at both ends, and bend it slowly. Bend it more, until it snaps or springs back. How is that like rock building up stress?
Do this with a grown-up60. Slow Motion Puzzle! Why Do Earth's Plates Move?
Try this with a grown-up. Warm a pan of water gently, and drop in a little food coloring. Watch the color rise, spread, and sink in loops. How is that like the mantle moving the plates?
Do this with a grown-up61. Up, Up, Up! Why Do Mountains Rise?
Try this with a grown-up. Lay a towel flat on a table, and push both ends toward each other. Watch the middle fold up into a ridge. How is that like plates making mountains?
Do this with a grown-up62. Deep Cuts! Why Do Canyons Get Deeper?
Try this with a grown-up. Pour a little water down a pile of sand, outside. Watch the tiny channel it carves. What happens if you pour faster?
Do this with a grown-up63. Rock Breakers! Why Does Weather Break Rock?
Try this with a grown-up. Fill a small plastic container to the top with water, and put a lid on it. Freeze it overnight, and look at what happens. What does the ice do to the lid?
Do this with a grown-up64. Wiggle Wiggle! Why Do Rivers Curve?
Try this with a grown-up. Pour a slow stream of water down a slope of damp sand outside. Watch how the stream starts to bend. Where does the sand pile up?
Do this with a grown-up65. Backward Bound! Why Do Waterfalls Move Backward?
Try this with a grown-up. Pour a stream of water over the edge of a soft sand pile, outside. Watch the edge crumble backward. Why does the soft part go first?
Do this with a grown-up66. More Than Mud! Why Is Soil More Than Dirt?
Try this with a grown-up. Fill a clear jar with garden soil and water, shake it, and let it settle. Watch the layers of sand, silt, and clay form. Which layer settles first?
Do this with a grown-up67. Dry Lands! Why Do Deserts Form?
Try this with a grown-up. Set a damp cloth in the sun, and another in the shade. Check which one dries first. What does dry, sunny air do to water?
Do this with a grown-up68. Always Wet! Why Do Rainforests Stay Wet?
Try this with a grown-up. Put a clear plastic bag over a leafy branch outside, and tie it closed. Come back in a few hours and look inside. Where did the water droplets come from?
Do this with a grown-up69. Crack and Crumble! Another Look: How Weather Breaks Rock
Try this with a grown-up. Look for a crack in a sidewalk or a wall. Can you find a plant growing in it? What job is the plant doing to the crack?
Do this with a grown-up70. Long Journey! Why Can a Pebble Travel So Far?
Try this with a grown-up. Put a few chalk pieces in a jar with some water. Shake it for a few minutes, then look at the chalk. Why did the pieces get rounder?
Do this with a grown-up71. Underground Worlds! Why Do Caves Form?
Try this with a grown-up. Put a piece of chalk in a little vinegar, and watch the bubbles. The acid slowly eats the chalk, just like rain eats limestone. Why does a cave need so much time?
Do this with a grown-up72. Old Ground, New Ground! Why Is Land Not the Same Age?
Try this with a grown-up. Find two rocks from your neighborhood. Compare their color, grains, and feel. Which one do you think is older, and how could you check?
Do this with a grown-up73. Frozen Time Capsules! Why Study Ice Cores?
Try this with a grown-up. Freeze a tall glass of water with a few drops of food coloring added at different times. The colored layers are like years of snow. What can a bubble tell you that a rock layer cannot?
Do this with a grown-up74. Handle With Care! Why Can a Changing Earth Be Dangerous?
Try this with a grown-up. Sketch a simple map of your home, and mark two safe exits. Pick a meeting spot outside. Why does knowing how Earth works help you stay safe?
Do this with a grown-up75. Earth Detective Mode! How Do You Think Like One?
Try this with a grown-up. Pick one landscape from this expedition, like a canyon, a cave, or a volcano. Write one why-question about it. What clue would make your answer stronger?
Do this with a grown-upExpedition 4: First People and Old Tools (25)
76. Stone Age Toolkit! Why Did Early People Make Stone Tools?
Try this with a grown-up. Try to tear a piece of paper with only your fingernail. Then try again with the edge of a safe, blunt plastic knife. Why does a sharp edge beat a fingernail?
Do this with a grown-up77. Sharp Idea! Why Is a Sharp Flake a Big Invention?
First, picture one giant rock. It's heavy! Next, picture a pocketful of flakes. Which is easier to carry on a long walk? Then, what can a flake cut that a round stone can't? Real ancient flakes stay in museums, so we handle only copies called replicas.
Do this with a grown-up78. Fire Power! Why Did Fire Change How People Lived?
First, name two jobs that fire does after sunset. Next, imagine finding a ring of old stones with black ash in the middle. What might it tell you? Then, ask why people would keep a fire in one special spot. And remember, fire is a grown-up tool. Never start one alone!
Do this with a grown-up79. Let's Cook! Why Did People Start Cooking Food?
With a grown-up in the kitchen, watch a carrot before and after it's cooked. Does the color change? Does it feel softer? Then ask, what else does heat change besides taste? And why is sharing a meal part of the invention?
Do this with a grown-up80. Ancient Fashion! Why Did People Wear Skins and Plant Fibers?
Wear a thin sweater and feel how warm you are. Now add a loose jacket on top. Where is the extra warmth coming from? Then ask, why might plant fiber beat animal hide in a rainy season? And remember, sewing replicas is fine, but taking animal parts from the wild is not a kid job.
81. Follow the Herd! Why Did People Follow Animal Herds?
First, look at a map of a river and imagine a herd moving along it. Why would people set up camp near the river? Next, ask why the same camp might be used again and again. What does a river add to a route? Share your ideas!
82. Cave Artists! Why Did People Paint on Cave Walls?
First, look at a photo of a cave painting with a grown-up. What do you think the painting shows? Take turns guessing. Then ask, what can a picture teach that a tool cannot? And why would touching a painting be a loss for everyone?
Do this with a grown-up83. Hello From the Past! Why Are Handprints in Caves a Clue?
With a grown-up, make a paper handprint stencil at home. Never on a real cave wall! Place your hand on paper and trace around it. Compare a small hand to a big hand. What can size tell you? And why is the place part of the clue?
Do this with a grown-up84. Home Sweet Home! Why Did People Start Staying in One Place?
Here's a question: what must be true about food before staying pays off? Think about water, soil, and storage. Next, ask why a group might still choose to keep moving. Both choices can be clever. What do you think?
85. Seeds of Change! Why Did Farming Change Everything?
With a grown-up, plant a bean seed in a cup of soil. Give it water and sunlight, and watch it grow. Then ask, what new job could exist once extra food is stored? And what risk does a field add?
Do this with a grown-up86. Best Friends Forever! Why Did People Domesticate Dogs?
Watch a friendly dog from a distance, or look at photos of dogs. What jobs could a dog do that a stone tool cannot? Next, ask why being calm matters. Why would calm animals be easier to live with?
87. Grain Gains! Why Did People Grow Grain?
With a grown-up, look at some dry rice or oats, and some that have been left in water. Which one could you store for months? Next, ask why drying matters. And what risk stays even after a good harvest?
Do this with a grown-up88. Pots, Baskets, Big Deal! Why Did They Matter?
With a grown-up, compare a basket and a bowl. Which one can hold water? Which one is lighter? Next, ask what a pot can do that a basket cannot. And why is a broken shard still useful?
Do this with a grown-up89. Stitch by Stitch! Why Did People Make Needles?
With a grown-up, sew two pieces of felt together with a safe, blunt plastic needle. Notice how a hole at the end lets thread follow the needle. Then ask, why does the eye matter as much as the point? And what weather job does a seam do?
Do this with a grown-up90. Buried Treasures? Why Bury Tools With the Dead?
First, think about a favorite thing you own. Why might it be a goodbye gift? Next, ask what a tool in a grave could tell us. Then ask who should decide if a grave is studied. And remember, never dig at a mound. Tell a ranger if you find one.
91. Camp by the Water! Why Do We Find Old Camps Near Water?
Look at a map of your town. Where is the water? Next, ask, what three jobs can one river do for a camp? Then, why would a terrace keep clues safe? And remember, don't dig along riverbanks. Look and learn instead!
92. Colorful Clues! Why Did People Use Ochre?
With a grown-up, mix a little red clay or colored powder with water at a table. Paint a small shape on paper. Does it stay bright when it dries? Then ask, what can color say that a plain tool cannot? And why does red earth last so long?
Do this with a grown-up93. Row, Row! Why Did Boats Matter?
With a grown-up, float different things in a tub. Try a leaf, a sponge, and a foil boat. Which ones float? Can they carry a small load? Then ask, what ideas can ride in a boat besides people? And why is a river like a road?
Do this with a grown-up94. Seashells Far From the Sea! Why Did People Trade Them?
Imagine finding a sea shell in a mountain camp. What does it prove? Why would people carry something they can't eat? Next, look at a map and trace a possible trade path. Who might have passed it along?
95. Trash Talk! Why Is a Midden Useful?
With a grown-up, look at your kitchen trash bag for one day. Just look, don't touch! What could a stranger learn about your meals? Next, ask what trash can tell you that a pretty tool cannot. And why do layers matter in a pile?
Do this with a grown-up96. Great Minds Think Alike! Why Did Groups Invent Similar Tools?
With a grown-up, look at photos of scrapers or blades from two different places. How are they alike? How are they different? Then ask, why might two groups never meet and still make a flake? And what stays local, even when the idea is similar?
Do this with a grown-up97. Show Respect! Why Treat Burial Sites With Respect?
First, ask, who is a burial for first? Next, think about what is lost if a site is looted. Then, what could you do if you find something old outside? Don't touch it. Tell an adult. Respect is part of good science.
Do this with a grown-up98. Look, Don't Touch! Why Use Replicas Instead of Real Artifacts?
Ask before you pick up a tool at a touch table. Then hold a replica. What can you learn from its shape and weight? Next, ask what clue lives only on the original. And why is the word replica a proud word, and not a cheat?
99. Many Groups! Why Were First People Not One Single Tribe?
With a grown-up, find a world map. Point to three very different places, like a desert, a forest, and a coast. Would people in each place need the same tools? What might be different?
Do this with a grown-up100. History Detective Mode! How Do You Think Like One?
Now, think like a detective! Pick one tool from this expedition, like a flake, a needle, or a pot. Ask, what is my why? What do I think it was for? Then ask, what second clue would make my why stronger? Write it down, and ask an adult to help you look it up.
Do this with a grown-upExpedition 5: How Scientists Know (25)
101. More Clues, Better Answers! Why Use More Than One Clue?
Look at one lone bone, or a picture of one. What second clue would make it more useful? Maybe where it was found, or what layer it was in. Then ask, why can one clue fool us? Thinking about that helps you become a better clue collector.
102. It's Okay Not to Know! Is "We Don't Know Yet" an Answer?
Pick something you don't know, like how many stars are in the sky. Say it out loud: we don't know yet! Then ask, why is a fake answer worse than a gap? And what turns not yet into a project? Great scientists love a good open question.
103. Mind Changers! Why Do Scientists Change Their Minds?
Think of something you believed when you were little, and then learned was different. What clue changed your mind? Next, ask why scientists save the old idea in their notes. How could that help others?
104. Half a Skeleton? Why Is a Fossil Not Always Whole?
Think about why a tooth might last when a rib does not. Next, look at a drawing of a partly found skeleton. What must a scientist mark when bones are missing? Marking gaps is honest science.
105. Copies Help! Why Do Museums Use Casts?
Press a coin into modeling clay, and lift it out. That's a mold! Now press fresh clay into it, or ask a grown-up to pour plaster. That's a cast! Then ask, what does a cast keep? And what can only the original still hold? Ask a museum guide which bones are real.
Do this with a grown-up106. Dating Rocks! Why Date the Rock Around a Fossil?
Stack five different colored books, or slices of bread, in a pile. Which was put down first? Which is the oldest? Then ask, why date the ash and not the bone? And what does a wide window still tell you?
107. Label It! Why Are Indexes and Catalogs Useful?
With a grown-up, give five of your toys or rocks their own numbers. Make a little card for each one. Then ask, what two facts must a catalog line hold? And why isn't a photo enough alone?
Do this with a grown-up108. Sharing Is Caring! Why Do Scientists Share Their Finds?
Draw a rock you found, or take a photo of it. Show it to a friend. What do they notice that you missed? Then ask, what can a second team notice that the first team loved too much to see? And why is a photo a kind of sharing?
109. Sketch It! Why Is a Drawing Useful in a Photo World?
Pick a leaf or a shell, and look at it for one whole minute. Then draw it, and add three labels with arrows. Ask, what can a drawing show that a photo hides in clutter? And why do labels belong on the sketch?
110. Measure Up! Why Measure Instead of Just Looking?
Find three leaves, and measure each one with a ruler. Measure twice, and write the numbers down. Then ask, what comparison is impossible with only the word big? And why do we measure twice?
111. Just a Pinch! Why Do Scientists Take Tiny Samples?
Look at a cookie, and think: what could a tiny crumb tell us? Would it show the flavor? The ingredients? Then ask, what can a speck tell that a photo cannot? And why keep the rest of the object intact? Small clues can carry big information.
Do this with a grown-up112. Friendly Disagreement! Why Can Two Teams Disagree?
With a friend, look at the same cloud or picture. Do you see the same thing? Explain why with clues. Then ask, what would settle a disagreement better than a louder voice? And why keep both write-ups?
113. Double Check! Why Is Peer Review a Filter?
Write a short claim, like: cats are faster than turtles. Trade with a friend, and let them ask a hard question. Then ask, what hole should a reviewer look for first? And why is try again useful?
114. Back to the Dig! Why Return to the Same Site?
Ask this: what can a second visit see that the first one could not? Try it at home. Draw a map of a room, and mark where things are. Ask yourself: why map before you leave? Then look again next week, and add what changed.
115. Where It Was Found Matters! Why Is Context So Important?
Ask: what story is lost if you only keep the object? And ask: why do we photograph it first? Try it at home: pick a toy on the floor, and take a picture before you move it. Then write down where it was, and what was next to it.
116. X Marks the Spot! Why Do Maps of Finds Matter?
Ask: what does a cluster of finds along a river suggest? And why can a blank area be a clue? Try it at home: draw a map of your yard or a room. Put a dot where each toy is. What pattern do you see?
117. One Tooth Tells All? Why Can a Single Tooth Be Enough?
Ask: what can wear tell you that shape cannot? And ask: why do scientists still hunt for more bones? Try it at home: look at your own teeth in a mirror. Which ones are pointy, and which ones are flat? What are they for?
118. Tiny Details! Why Use Microscopes on Old Dirt?
Ask: what plant clue can pollen give that a big bone cannot? And ask: why label the bag first? Try it at home: sprinkle salt and pepper on a plate. Use a magnifying glass and count how many kinds of specks you can see.
119. Famous Fossil? Why It's Not the Whole Story!
Ask: what can a common bone teach that a poster fossil cannot? Try it at home: collect 10 pebbles, or 10 leaves. Which one is the most unusual? And what does normal look like? The plain ones help you notice the special one!
120. Team Earth! Why Work With Local Communities?
Ask: what can a local guide know that a lab cannot? And ask: why share finds back? Try it at home: ask an elder or neighbor what your street looked like long ago. Then say thank you, and share what you learned.
121. Keep Out? Why Are Some Sites Closed to the Public?
Ask: what does a fence protect that a sign alone cannot? And ask: where can you still see the finds? Try it at home: build a block tower, and put a rope around it. Notice how the rope reminds people to keep their hands off!
122. Stop, Thief! Why Is Looting a Science Problem?
Ask: what two facts can never be bought back? The place where it was found, and what was around it. And ask: why is leaving a find where it is a kind of discovery? Then tell a friend why notes matter.
123. Big Questions! Why Do Kids' Questions Still Matter?
Ask: what question from this book is still open for you? And ask: who could help you test it? Try it at home: write down one big why, on paper. Put it somewhere safe, and come back to it next week.
124. Write It Down! Why Is a Notebook a Tool?
Ask: what would you lose if you only took a photo? And ask: why date the page? Try it at home: start a nature notebook. Write today's date, the place, and one thing you noticed. Then add one question you still have.
125. Detective Mode On! How Do You Think Like a Detective?
Ask: which of the five moves do you skip most often? And ask: what would change if you added it? Try it at home: pick a mystery, like why the puddle is gone. Then use the five moves to solve it!
Expedition 6: Clocks and Your Time (25)
126. Happy New Year! Why Do We Count Years?
Ask: what would repeat if Earth did not orbit the Sun? And ask: why is a birthday an orbit party? Try it at home: walk around a lamp in a circle. That's one orbit. How old are you in trips?
Do this with a grown-up127. Sun Up, Sun Down! Why Do We Have Days and Nights?
Ask: if Earth stopped spinning, what would a day mean? And ask: why is night not the Sun turning off? Try it at home: use a lamp and a ball, in a dark room. Slowly spin the ball, and watch the light move across it.
Do this with a grown-up128. Hot, Cold, Repeat! Why Do Seasons Change?
Ask: what would seasons do if Earth had no tilt? And ask: why can two kids have opposite seasons on the same day? Try it at home: watch one tree all year. Take a photo every month, and see the seasons change!
129. Moon Shapes! Why Does the Moon Change Shape?
Ask: what is really changing, the Moon or the slice we see? And ask: why is a new Moon still there? Try it at home: look at the Moon each night for a week. Draw its shape in your notebook.
130. Counting Years! How Do People Keep Track of Them?
Ask: what would you use to count time if you had no calendar? Try it at home: make a family timeline. Draw a line, and mark the year you were born. Add other big days, like your first day of school.
131. Time Travelers? Why Are There Time Zones?
Ask: why can it be breakfast for you and dinner for a cousin? And ask: what would one world clock do to lunchtime? Try it at home: pick a far-away city. Look up what time it is there right now.
132. Tree Rings! Why Do Rings Count Years?
Ask: what could a thin ring mean? And ask: why do two trees nearby often match? Try it at home: find a picture of a tree slice. Count the rings, and find the thinnest one.
Do this with a grown-up133. Swing and Sand! Why Do Some Clocks Use Swings or Sand?
Ask: what must stay the same for a swing to be a fair clock? And ask: why do we reset the sand? Try it at home: tie a small weight to a string. Swing it, and count 10 swings. Then try a shorter string!
134. Deep Time! Why Can't We Wear a Clock for It?
Ask: why would a birthday cake be a bad mountain clock? And ask: what clock is right for a school day? Try it at home: list three things you can time. Pick the best clock for each one, like a stopwatch or a calendar.
135. Tick Tock, Body Clock! Why Does Your Body Have Rhythms?
Ask: why does a late night make the morning hard? And ask: what outside cue helps a body clock? Try it at home: put two fingers on your neck or wrist, and feel your pulse. Count the beats for 15 seconds. Then jump 10 times and count again!
Do this with a grown-up136. Ring Around the Tree! Another Look at Tree Ring Time
Ask: why do two trees nearby often match? And ask: what could a really thin ring say about that year? Try it at home: draw a stump with 10 rings. Make two rings thin, and imagine what happened those years.
Do this with a grown-up137. Before and After! Why Does That Order Matter?
Ask: what change would you miss with only one picture? And ask: why keep the date on both? Try it at home: take a photo of a plant or a puddle today. Take another in a week, and compare them. What changed, and what stayed the same?
138. Be Patient! Why Do Some Answers Take Time?
Ask: what question cannot be answered in ten minutes? And ask: why write the wait-days down? Try it at home: soak a bean in a wet paper towel. Look every day, and write down what changed. Does it sprout on day 3, or day 5?
139. Yesterday vs. Tomorrow! Why Do They Feel Different?
Ask: what can you do today that yesterday cannot change? And ask: why write a plan down? Try it at home: write one thing you learned yesterday. Then write one plan for tomorrow, and check it off! That's time travel with a pencil.
140. Why Does History Use Different Clocks Than Homework?
Ask: when is about more honest than a fake exact year? And ask: why not time a dinosaur with a stopwatch? Try it at home: how long does it take to brush your teeth? Then guess how old your street is. Which one needs exact numbers, and which one needs the word about?
141. Same Age, Different Look! Why Can Two Fossils Differ?
Ask: what could a fossil's shape tell you about its home? And ask: why does a date alone not tell the whole story? Try it at home: pick 2 animals in your yard or a book. Say when they live, and where they live.
142. A Tiny Slice! Why Is Your Life a Small Part of Earth Time?
Ask: what can a short life still measure well? And ask: why does a tiny slice still get a notebook? Try it at home: draw a line across a long paper for Earth's age. Then find a spot for your birthday, and for today.
143. Save It for Later! Why Do We Save Finds for the Future?
Ask: what new tool might exist when you are grown? And ask: why do labels travel with the box? Try it at home: pick one thing you want to keep. Write where and when you found it, then store it safely. You just made a tiny museum.
144. You're a Timekeeper! Why Can You Be One Too?
Ask: what would you measure once a year? And ask: why does the date make a mark scientific? Try it at home: mark your height on a door frame. Write today's date, and check again next year. Your clock is now ticking!
145. Tick, Tock, Ding! Why Are There So Many Kinds of Clocks?
Ask: which clock fits popcorn, and which fits a mountain? And ask: why not swap them? Try it at home: list 3 things around your house that keep time. Which is the fastest, and which is the slowest?
146. Bonus Day! Why Do Some Years Get an Extra Day?
Ask: what would happen if we never added the day? And ask: why is a quarter day a problem over many years? Try it at home: find February on a calendar. Check if this year has a 29.
147. Layer by Layer! Why Are Older Layers Usually Lower?
Ask: what would a fold do to 'lower means older'? And ask: why do scientists still love the stacking rule? Try it at home: stack 4 different books or towels. Which one went down first? That one is the oldest, and it should be at the bottom.
148. Are We There Yet? Why Does Waiting Feel So Long?
Ask: why does a fun recess seem to vanish? And ask: what could you measure to check the feeling against the clock? Try it at home: use a timer for a 1 minute wait. Guess how long it was first, then check! Were you close?
149. The End Is Yours! Why Does This Book End With You?
Ask: which expedition would you reopen first? And ask: which why is still open in your house? Try it at home: open to a blank page. Write the next question you wonder about.
150. Time Detective Mode! How Do You Think Like One?
Now, think like a time detective! Ask: what clock will you use this week? And ask: what why will you write on the first blank page? Try it at home: pick one activity from the book. Do it this week, and write the date. Then tell a friend what you found.