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Plant, tree and rainforest questions for kids
Here are 313 questions about plants, trees and forests from 20 A Million Whys books, each with a short video answer. Book 17, The Rainforest Expedition is all about plants, trees and forests, and the rest come from other books in the series. Tap any question to watch the video and read the answer.
From Book 17: The Rainforest Expedition (150)
What Is a Rainforest, and Where in the World Are Rainforests Found?
A rainforest is a thick, green forest that gets a great deal of rain, usually more than 80 inches a year! Most are tropical, growing in a warm belt around the middle of the Earth.
How Is a Tropical Rainforest Different From a Temperate Rainforest?
A tropical rainforest is hot and wet all year, near the equator. A temperate rainforest is cooler, and grows near the ocean where rain and fog roll in.
Why Do Tropical Rainforests Grow in a Belt Around the Middle of the Earth?
Near the equator, the Sun shines almost straight down all year long. That keeps the land and sea warm, and warm air makes lots of rain.
What Are the Four Layers of a Rainforest?
A rainforest has four layers, like floors in a tall building. From top to bottom they are the emergent layer, the canopy, the understory, and the forest floor.
Why Do a Few Rainforest Trees Poke Up Above All the Others?
Trees in the emergent layer stretch up 150 feet or more, which is 45 meters, to catch the brightest sunlight. They also catch the breeze that carries their pollen and seeds.
Why Is the Canopy Called the Roof of the Forest?
The canopy is the thick layer where the branches and leaves of most tall trees meet. It is about 60 to 100 feet up, which is 18 to 30 meters.
What Is the Understory, and Why Is It So Still and Shady?
The understory is the layer under the canopy where young trees, shrubs, and ferns grow. Only a small amount of sunlight filters down, and the canopy blocks the wind.
Why Is the Rainforest Floor So Dark?
The thick canopy and understory catch most of the sunlight before it reaches the ground. In some rainforests, only about 2 percent of the light makes it to the floor.
Why Are So Many Rainforest Trees Tall and Skinny with No Branches Near the Ground?
Rainforest trees race one another for sunlight. A tall trunk with no low branches grows fast toward the light.
How Tall Can a Rainforest Tree Grow?
Some tropical trees grow more than 200 feet tall, which is 60 meters and taller than a 20-story building. In Borneo, scientists have measured trees almost 330 feet tall.
Why Does the Air Under the Trees Feel Like a Warm, Wet Blanket?
Trees release water vapor from their leaves, and the thick canopy traps that moisture and keeps the wind out. So the air near the ground can be nearly 100 percent humid.
Why Does the Temperature Stay Almost the Same All Year in a Rainforest?
Near the equator, the Sun's strength barely changes through the year, so every month is warm. Clouds and the thick canopy also keep days from getting scorching and nights from getting cold.
How Many Kinds of Living Things Live in a Rainforest?
Rainforests hold more kinds of plants and animals than any other land habitat. They cover only about 6 percent of Earth's land, yet by many estimates they are home to more than half of all land species.
Why Can a Small Patch of Rainforest Hold Hundreds of Kinds of Trees?
In many forests, a few kinds of trees dominate. In a rainforest, each kind of tree is rare, so a small patch may have hundreds of different trees with only a few of each.
Why Is a Rainforest So Loud?
A rainforest is packed with animals that call, buzz, and chirp. Frogs sing, insects click and hum, birds shout, and monkeys howl.
Why Does the Rainforest Smell Earthy and a Little Sweet?
The rainforest smell comes from busy recycling. Fallen leaves, wood, and fruit are broken down by fungi and bacteria, which release smelly gases.
Are Rainforests Really the Lungs of the Earth?
You may have heard that rainforests are the lungs of the Earth, but that saying is mostly a myth. Rainforest plants do make lots of oxygen, but the forest's animals, fungi, and bacteria use up almost as much.
Why Are There So Many Insects in Rainforests?
Warm, wet weather all year means insects never have to sleep through a winter. There are plenty of leaves, flowers, wood, and fruit to eat, plus countless hiding places.
How Do So Many Animals Share One Rainforest Without Crowding Each Other Out?
Each kind of animal has its own job, food, and place to live. Scientists call this a niche.
What Is a Cloud Forest?
A cloud forest grows high on a tropical mountain, where clouds drift right through the trees. The air is cool, damp, and misty all day long.
What Lives in a Temperate Rainforest on the Pacific Coast?
The Pacific coast has huge trees like western red cedar, Sitka spruce, and western hemlock, along with ferns and thick moss. Black bears, wolves, bald eagles, and salmon live there too.
Why Are Temperate Rainforests Covered in Moss?
Moss loves damp, cool, shady places, and temperate rainforests have plenty of all three. Moss has no roots to take up water, so it soaks it up straight from the air and rain.
Why Do Some Rainforests Flood for Part of the Year?
In the Amazon basin, heavy rains and melting snow far away make rivers rise as much as 30 or 40 feet for months. The water spreads into the forest, creating a flooded forest.
Where Are the Biggest Rainforests on Earth?
The Amazon in South America is the largest rainforest on Earth. It covers an area about two thirds as big as the lower 48 United States.
How Old Are Rainforests?
Some rainforests are among the oldest living ecosystems on Earth. The Daintree Rainforest in Australia is estimated to be about 180 million years old.
What Happens to a Raindrop on Its Way Down Through the Forest?
A raindrop hits the canopy first. Some drops cling to leaves and evaporate straight back into the air, while others drip from leaf to leaf or run down branches and trunks.
Why Does It Rain Almost Every Afternoon in Some Rainforests?
In some rainforests, it rains almost every afternoon like clockwork! In the morning, the Sun heats the forest and water evaporates into the air.
How Does a Rainforest Help Make Its Own Rain?
Trees pull water from the soil and release it as vapor through tiny pores in their leaves. This is called transpiration.
What Are the Flying Rivers of the Amazon?
Flying rivers are streams of water vapor that flow through the air above the rainforest, carried by winds. They bring moisture from the Atlantic Ocean across the forest, and the trees add more along the way.
Why Does Mist Rise From the Forest After a Storm?
After a storm, the leaves, branches, and ground are warm and wet. When the Sun comes out, water evaporates into the cooler air above.
Why Is Rainforest Soil Poor Even Though Plants Grow So Thickly?
Rainforest soils are old, and heavy rain keeps washing the nutrients down and away. Most nutrients are locked inside living plants and fresh leaf litter.
How Can Giant Trees Grow in Poor Soil?
Most rainforest trees have shallow, wide roots that spread through the top few inches of soil. That is where fallen leaves rot and release nutrients.
Why Does a Fallen Leaf Disappear in Just a Few Weeks?
In the warm, wet air of the rainforest, decomposers work very quickly. Fungi, bacteria, termites, and other tiny animals break down dead leaves into simple nutrients that plants can use again.
Why Do Mushrooms and Other Fungi Love the Forest Floor?
Fungi are the forest's recyclers. They grow long, thread-like strands through dead leaves and wood, digesting them from the outside.
Why Are Termites and Beetles Good for a Forest?
Termites and wood-boring beetles chew dead trees into small pieces. Inside termites' guts live tiny microbes that digest wood.
What Happens When a Giant Tree Falls in a Rainforest?
A falling tree can drag down vines and smaller trees, opening a gap in the canopy. Sunlight pours in, and seedlings that had been waiting in the shade race upward.
Why Do Tiny Seedlings Wait in the Shade for Years?
Seedlings that start in the dark can't grow much, so they stay small and grow very slowly. Sometimes they wait for decades, saving their energy.
Why Can a Tropical Sapling Shoot Up So Quickly?
Plants need sunlight, water, and warmth, and a rainforest has all three nearly all year. There is no winter to stop growth, so plants can keep making leaves, wood, and fruit.
How Do Rainforest Trees Soak Up Carbon Dioxide and Store It?
Leaves take in carbon dioxide from the air. With sunlight and water, they use it to make sugars.
Why Is the Rio Negro Black Like Tea?
The Rio Negro, a big river in the Amazon, gets its dark color from natural chemicals that seep out of rotting leaves and roots. It works just like tea coloring water.
Where Do Animals Shelter When It Pours in the Rainforest?
When it pours in the rainforest, many animals tuck under large leaves, crawl into tree holes, or burrow into the ground. Birds sit close to the trunk or under thick leaves, and butterflies fold their wings.
What Are Sunflecks, and How Do Small Plants Use Them?
Sunflecks are small patches of sunlight that slip through gaps in the canopy and move across the forest floor. They last only seconds or minutes.
How Do Scientists Measure the Weather Inside a Rainforest?
Scientists set up tall towers topped with instruments, plus rain gauges and sensors on the forest floor. They measure temperature, humidity, wind, and the gases trees breathe in and out.
Why Do Some Tropical Forests Drop Their Leaves in the Dry Season?
Not all tropical forests are wet all year. In places with a long dry season, many trees shed their leaves to save water.
What Does a Rainforest Look Like From Space?
From space, the Amazon looks like a deep green blanket crossed by winding brown rivers. Towering clouds often rise above it in the afternoon.
What Is the Difference Between a Rainforest and a Jungle?
A rainforest is a tall forest with a thick canopy, and most of its floor is shady and fairly open. A jungle is a tangled, thick growth of plants, often found at forest edges, along riverbanks, or where sunlight reaches the ground.
What Is Humus, and Why Is the Layer of Good Soil So Thin in a Rainforest?
Humus is dark, crumbly material made from rotted plants and animals. It stores nutrients and water for plant roots.
How Does a Forest Heal Itself After a Storm or Landslide?
After a storm or landslide, fast-growing pioneer plants, such as Cecropia trees and ferns, spring up in the open light. They shade the soil and make it better for others.
Can a Rainforest Change the Weather Far Away?
Yes! Scientists have found that moisture released by the Amazon travels with the wind.
How Do Insects and Frogs Take Advantage of the Rainy Season?
When the rains arrive, many frogs gather at fresh pools and breed. Insects also emerge in huge numbers, because fresh leaves and puddles provide food and places for eggs and young.
How Do Monkeys Swing and Leap From Branch to Branch?
Monkeys and apes swing and leap using strong arms, grippy hands, and clever balance! Gibbons swing hand over hand, and many monkeys jump between branches.
Why Do Some Monkeys Have Tails That Can Grab Like a Hand?
Some monkeys have tails that grip like an extra hand! Spider monkeys and howler monkeys have grabbing tails, which scientists call prehensile.
How Do Animals Glide From Tree to Tree?
Some rainforest animals cannot fly, but they can glide! They spread out skin, ribs, or feet like a parachute and sail from tree to tree.
How Do Tree Frogs Stick to Leaves?
Tree frogs have sticky toe pads that cling to leaves, even wet, upside-down ones! The pads are covered in tiny bumps and a thin layer of slippery liquid.
What Is the Smallest Frog in the World?
The smallest frog in the world is only about as long as a small pea! It lives in the rainforest of Papua New Guinea.
Why Are So Many Rainforest Birds Brightly Colored?
Rainforest birds wear bright colors to send messages! Colors help birds find friends, show they are healthy, and tell their own kind from look-alikes.
How Do Fruit Bats Find Ripe Fruit in the Dark?
Fruit bats find ripe fruit in the dark using a super sense of smell and big, night-ready eyes! They can sniff a ripe fruit from far away.
Why Do Howler Monkeys Howl So Loudly?
Howler monkeys howl so loudly because their bodies have a built-in loudspeaker! A special enlarged throat bone works like an echo chamber.
How Do Weaver Ants Build Nests From Living Leaves?
Weaver ants build their nests by pulling living leaves together and stitching them with silk! Hundreds of workers team up for the job.
How Do Sleeping Animals Stay Safe in the Treetops?
Sleeping animals stay safe in the treetops by choosing places that hunters cannot easily reach! Some sleep in nests, some in tree holes, and some on thick branches.
How Can a Snake Climb a Smooth Tree Trunk?
Tree snakes climb smooth trunks using light bodies, grippy belly scales, and clever curves! Even tiny bumps in the bark give them something to push against.
Why Do Orangutans Build a New Bed in the Trees Each Night?
Orangutans build a fresh bed in the trees every night! They live in the rainforests of Borneo and Sumatra.
How Do Chimpanzees Use Sticks as Tools?
Chimpanzees are tool users who turn sticks into fishing rods and nutcrackers! They strip leaves from a twig to make a tool for fishing termites out of their mound.
How Can a Frog Become See-Through?
Glass frogs have almost see-through bellies, and they can become even clearer when they rest! You can see their hearts and organs through their skin.
Why Do Butterflies Gather at Muddy Puddles?
Butterflies gather at muddy puddles to get minerals they cannot find in nectar! Scientists call this behavior puddling.
Why Do Animals Use Vines as Highways?
Animals use woody vines called lianas as highways high above the ground! Lianas wrap from tree to tree, making bridges across gaps in the canopy.
How Do Rainforest Animals Avoid Shouting Over One Another?
Rainforest animals share the soundscape like singers in a choir! Each species tends to call at its own pitch or its own time.
Why Do Some Rainforest Animals Eat Clay?
Some rainforest animals eat clay because it gives them things their food lacks! Parrots and macaws gather at steep riverbanks called clay licks.
How Do Animals High in the Canopy Get Water to Drink?
Animals high in the canopy drink from tiny pools and puddles in the treetops! Plants called bromeliads catch rain in their leaves like little cups.
Who Shows Up When a Fig Tree Is Full of Fruit?
A fig tree full of fruit is like a giant buffet, and the whole forest comes to eat! Monkeys, parrots, toucans, bats, and many other animals visit at all hours.
How Can One Rainforest Tree Hold Thousands of Insects?
One rainforest tree can be a whole city for insects! Scientists counted thousands of insects living in the branches of a single treetop.
Why Do Monkeys Spend So Much Time Grooming Each Other?
Monkeys groom each other to clean fur and to build friendships! Grooming removes dirt and tiny pests from fur.
How Do Canopy Animals Know Which Tree Is Fruiting?
Canopy animals find fruiting trees using their eyes, their noses, and their memories! A ripe tree sends out clear signals.
Why Do Morpho Butterflies Flash Bright Blue?
A morpho butterfly's wings flash bright blue because of tiny structures, not blue paint! The wing scales bounce blue light back to your eyes.
Why Do So Many Animals Live in the Canopy Instead of on the Ground?
So many animals live in the canopy because that is where the food and sunlight are! The treetops are full of leaves, flowers, and fruit.
Why Do Rainforest Leaves Have Long, Pointed “Drip Tips”?
Many rainforest leaves end in a long, pointed tip called a drip tip! It works like a spout, letting rainwater run off the leaf quickly.
Why Do Some Rainforest Trees Have Giant Flared Roots Like Walls?
Buttress roots are giant, wall-like ridges that help tall trees stand up! Rainforest soil is thin, so tall trees need extra support.
What Is an Epiphyte, and Why Do Some Plants Grow on Other Plants?
An epiphyte is a plant that grows on another plant without harming it! Ferns, mosses, orchids, and bromeliads often live this way.
How Do Bromeliads Hold Tiny Ponds in the Treetops?
A bromeliad is a plant with leaves that form a cup, and the cup holds a tiny pond! Rainwater collects in the center, high up in the treetops.
How Does a Strangler Fig Grow Around Another Tree?
A strangler fig starts life high in a tree and slowly wraps around it! Its roots grow down the trunk to the soil.
Why Are Orchid Seeds as Tiny as Dust?
Orchid seeds are as tiny as dust so the wind can carry them far away! One seed pod can hold millions of seeds.
Why Do Some Plants on the Forest Floor Have Leaves as Big as Umbrellas?
Some plants on the forest floor have leaves as big as umbrellas because the floor is dim! Only a little sunlight filters down through the canopy.
What Is the Titan Arum, and Why Does It Smell Terrible?
The titan arum is a giant rainforest plant that smells terrible on purpose! It makes one of the largest flower clusters in the world.
How Do Pitcher Plants Trap Insects?
Pitcher plants trap insects in cup-shaped leaves with a slippery rim! Inside the cup is a pool of liquid that digests the insects.
Why Are Leaves at the Top of the Canopy Smaller and Tougher than Those Below?
Leaves at the top of the canopy are small and tough, while leaves below are big and thin! The top gets hot, windy, and very sunny.
Why Do the Leaves of a Sensitive Plant Fold Up When Touched?
The sensitive plant folds up its leaves in seconds when it is touched! It is called the mimosa, and it comes from the tropical Americas.
How Can a Vine Grow Hundreds of Feet Without a Thick Trunk?
Lianas are woody vines that reach the sunny canopy without growing a thick trunk! They start as seedlings on the ground.
How Does a Cacao Pod Turn Into Chocolate?
Chocolate starts as seeds inside a pod that grows on a cacao tree! The tree grows in the shade of the rainforest.
Why Do Some Tropical Fruit Trees Grow Flowers and Fruit Right on Their Trunks?
Some tropical trees grow flowers and fruit right on their trunks! Cacao and jackfruit trees are famous for it.
Why Do Rainforest Fruits Come in So Many Colors?
Rainforest fruits come in many colors to advertise to the animals that spread their seeds! Color and smell are like signs saying, ripe and ready, come and get me.
Why Do Some Rainforest Seeds Spin Like Helicopters?
Some rainforest seeds have a wing that makes them spin like tiny helicopters! Tall trees, such as dipterocarps in Southeast Asia, use this trick.
Why Can’t Brazil Nut Trees Grow Well Without a Rodent and a Bee?
Brazil nut trees need two helpers, a big bee and a rodent called the agouti! The bee pollinates the flowers, and the agouti plants the seeds.
How Do Some Rainforest Plants Call for Bodyguards?
Some rainforest plants call for bodyguards when they are being eaten! They release a special scent into the air.
Why Do Some Tree Trunks Bristle with Spikes?
Some tree trunks bristle with spikes to protect them while they are young! Certain palms and kapok trees grow sharp thorns on their trunks.
What Is the World’s Biggest Flower, and Why Does It Have No Leaves?
The world's biggest single flower is the rafflesia, and it has no leaves at all! It grows in the rainforests of Southeast Asia, in places such as Indonesia.
Which Plant Has the Longest Leaves in the World?
The raffia palm has the longest leaves of any plant in the world! Its leaves can be over 80 feet long, or about 25 meters.
Why Are Young Leaves on Many Rainforest Trees Red or Pink?
Many rainforest trees send out new leaves that are red, pink, purple, or even white! The color is only temporary, like a costume.
How Can a Giant Water Lily Leaf Be So Big and So Strong?
The giant Amazon water lily has floating leaves up to 10 feet wide, and they are surprisingly strong! The secret is a hidden web of ribs underneath.
How Do Rainforest Plants Race Each Other for Sunlight?
Rainforest plants race each other for sunlight, and the race never ends! Down on the floor, it is very dark.
Do Scientists Still Find New Rainforest Plants?
Yes, scientists still find new rainforest plants every single year! Around the world, about two thousand new plant species are named each year.
Why Do Leafcutter Ants Carry Pieces of Leaves They Never Eat?
Leafcutter ants carry leaf pieces home, but they never eat them! The leaves are food for a garden.
How Do Army Ants Build Bridges with Their Own Bodies?
Army ants link their own bodies together to make living bridges! When a gap is in the way, workers hold on to each other with their legs and tiny hooks.
Why Do Some Ants Live Inside Special Trees?
Some ants live inside special trees because the tree gives them a home and food! In return, the ants protect the tree from hungry insects and smothering vines.
How Do Fig Wasps and Fig Trees Depend on Each Other?
Fig trees and fig wasps need each other to make the next generation! The tiny wasp carries pollen to the tree, and the tree gives the wasp a place for its babies.
What Does It Mean When Two Living Things Are Partners?
When two living things are partners, they help each other so both do better! Scientists call this mutualism, and it means both win.
How Do Hummingbirds and Heliconia Flowers Fit Together Like a Lock and Key?
Some rainforest hummingbirds and flowers fit together like a lock and key! The bird's beak and the flower's tube have the same curve.
Why Do Birds Visit Red Flowers but Bees Prefer Blue and Yellow?
Flowers use color to invite the right visitors! Birds can see red very well, but bees see colors differently, so red looks dull to them.
How Do Some Birds Follow Army Ants to Find Food?
Some birds follow army ants because the ants chase food out of hiding! The birds do not eat the ants.
How Does a Bucket Orchid Make Bees Take a Bath?
A bucket orchid has a flower shaped like a bucket, filled with liquid! Male orchid bees come to collect its perfume, and some slip in for a splash.
How Do Dung Beetles Help the Forest Floor?
Dung beetles are the clean-up crew of the forest floor! They roll or bury animal droppings, which puts nutrients back into the soil.
How Do Poison Dart Frog Parents Carry Tadpoles to Tiny Pools?
Poison dart frog parents carry their tadpoles to tiny pools high in the trees! The tadpoles wriggle onto a parent's back and ride up the trunk.
How Can a Frog Smaller than Your Thumb Be So Loud?
A tiny frog can be loud because it uses its whole body like a speaker! The coquí frog of Puerto Rico is about the size of a quarter.
Why Do Some Rainforest Spiders Live Together in Giant Webs?
Most spiders live alone, but a few kinds in the Amazon live in big family groups! Hundreds or thousands share one giant web.
Why Are There More Kinds of Beetles than Anything Else?
There are more kinds of beetles than any other animal group! About one out of every four known animal species is a beetle.
Why Do Some Rainforest Bees Have No Sting?
Some rainforest bees have no sting at all! Their stingers are so small that they do not work.
Why Does the Atlas Moth Have No Mouth as an Adult?
The atlas moth has no working mouth as an adult because it does all its eating as a caterpillar! It stores up fat, and that fat powers its short adult life.
What Lives in a Handful of Rainforest Soil?
A handful of rainforest soil is like a tiny hidden city! It is packed with living things, most too small to see without a microscope.
How Strong Is a Rhinoceros Beetle?
Rhinoceros beetles are super strong for their size! Some, like the Hercules beetle, can lift many times their own weight.
How Do Big Fruit-Eating Birds Plant New Trees?
Big fruit-eating birds are gardeners of the forest! They swallow whole fruit, carry the seeds far away, and drop them in new places.
How Do Glasswing Butterflies Get See-Through Wings?
Glasswing butterflies have see-through wings because of tiny structures, not color! Their clear wings have almost no colored scales.
Why Does the Durian Fruit Smell So Strong?
The durian fruit smells so strong because its smell is a signal to animals! In the forests of Southeast Asia, the smell calls hungry animals from far away.
Who Works the Night Shift in the Rainforest?
When the Sun sets, a whole different crew wakes up in the rainforest! Night animals come out to eat, hunt, and sing.
What Tiny Flies Pollinate Chocolate Trees?
Chocolate trees are pollinated by tiny flies called midges, not by bees! Without these little insects, there would be far fewer cocoa beans.
What Is a Keystone Species in a Rainforest?
A keystone species is one that many other living things depend on! It matters much more than you would expect from how many there are.
What Can Happen to a Rainforest If One Kind of Animal Disappears?
In a rainforest, animals and plants are linked like threads in a web! When one kind of animal disappears, other living things can be affected too.
How Do Scientists Reach the Top of a Rainforest?
Scientists reach the top of a rainforest with special gear, training, and a lot of care! The treetops are called the canopy, and they are full of life.
What Is a Canopy Walkway, and Why Do People Build Them?
A canopy walkway is a bridge of ropes and boards strung between tall trees! It lets people walk safely through the treetops.
How Do Scientists Use Sound Recorders to Listen to a Rainforest?
Scientists listen to the rainforest by hanging sound recorders in the trees! The recorders listen for days or weeks, even when no one is there.
How Do Drones and Lasers Help Scientists Map a Rainforest?
Drones and lasers help scientists map a rainforest without climbing every tree! Drones take photos from above, and lasers measure the height of the forest.
How Can Two Look-Alike Rainforest Animals Turn Out to Be Different Species?
Two animals can look almost the same and still be different species! Scientists look at calls, DNA, and who the animals mate with.
Why Do Scientists Put Numbered Tags on Rainforest Trees?
Scientists put numbered tags on rainforest trees so they can follow each tree for years! Every tag is like a name or a number for that tree.
What Medicines Come From Rainforest Plants?
Many medicines first came from plants, and rainforests hold a lot of plants! Scientists study them carefully in laboratories.
Which Foods That We Eat Began in Tropical Forests?
Many foods we eat began in warm tropical regions, and a number of them in or near rainforests! People now grow them on farms all over the world, so they can reach stores far away.
Which Tree Gives Us the Stretchy Material Called Natural Rubber?
Natural rubber comes from the milky sap of the rubber tree! The sap is called latex, and it first grew in the Amazon rainforest.
How Is Chewing Gum Linked to a Rainforest Tree?
Long ago, chewing gum was made from the milky sap of a rainforest tree! The sap is called chicle, and it comes from the sapodilla tree.
Why Does Soil Wash Away When Rainforest Trees Are Cut?
Soil washes away when trees are cut because trees protect the ground! Leaves slow down the rain, and roots hold the soil in place.
Why Are Some Rainforests Getting Smaller?
Some rainforests are getting smaller because people have cleared parts of them! Forest land has been used for farms, cattle, roads, mines, and wood.
What Happens to Animals When a Forest Is Cut Into Small Pieces?
When a forest is cut into small pieces, animals have a hard time finding what they need! Open ground can be a barrier, and small patches may lose species over time.
What Is Ecotourism, and How Can Visits Help a Forest?
Ecotourism means visiting nature in a way that protects it and helps local people! Visitors follow rules, stay on trails, and hire local guides.
What Is Shade-Grown Coffee and Why Does It Help Forests?
Shade-grown coffee is grown under tall trees instead of in open, sunny fields! The trees give homes to birds, bats, and insects.
How Does Planting Trees Help Heal a Rainforest?
Planting trees helps heal a rainforest by bringing back homes for wildlife! Groups collect seeds from native trees, grow them in nurseries, and plant them where the forest was lost.
What Can Kids Do to Help Rainforests?
Kids can help rainforests in lots of simple ways! Small steps by lots of people make a big difference.
What Jobs Do People Have Studying and Protecting Rainforests?
Lots of different jobs help us study and protect rainforests! Some people work with plants, some with animals, and some with machines.
How Do Rangers Help Protect Rainforest Animals and Plants?
Rangers help protect rainforest animals and plants by watching over the forest every day! They walk or boat through protected areas and work with nearby communities.
What Is a Protected Area, and Why Do Rainforests Need Them?
A protected area is land set aside so wildlife and plants can thrive! It might be a national park or a reserve, with rules about what people can do.
How Do Wildlife Rescue Centers Help Animals Return to the Forest?
Wildlife rescue centers care for animals that are hurt or have lost their parents! Their goal is to help each animal get ready to return to the forest.
Why Do Rainforests Matter to People Who Live Far Away?
Rainforests matter to people everywhere, even far away! They affect weather, store carbon, and shelter a huge share of Earth's wildlife.
How Do Birds That Visit Your Backyard Depend on Rainforests?
Many birds that visit your backyard spend part of the year in tropical forests! They nest in Canada and the United States in summer.
How Can a Jar of Plants Show How a Rainforest Recycles Water?
A closed jar of plants shows how a rainforest recycles water! Water rises, collects, and drips back down again, like a tiny rainforest in a jar.
What Do Scientists Still Wonder About Rainforests?
Scientists still wonder about lots of things in rainforests! Many living things have never even been named, because rainforests are so big and so full of life.
From Book 2: The Inside Expedition (1)
From Book 4: The Wild Expedition (30)
Why Are Leaves Green?
Leaves look green because they are packed with chlorophyll, a green tool. Chlorophyll catches sunlight, and that helps the plant make its own food.
Why Do Trees Have Bark?
Bark is a tree's coat and shield. It keeps out bugs, weather, and bumps that could hurt the soft parts inside.
Why Do Flowers Smell Sweet?
A sweet smell is like a billboard for a flower. It tells bees, butterflies, and other helpers that nectar and pollen are here.
Why Do Some Trees Lose Their Leaves?
Many trees drop their leaves before winter. That way they do not spend energy on parts that would freeze or dry out when the sun is weak.
Why Do Roots Grow Down?
Roots grow down because they follow gravity. Down is where soil holds moisture, and where a plant can anchor itself.
Why Do Plants Need Sunlight?
Sunlight is a plant's power source. Without it, chlorophyll cannot make sugar, and the plant slowly runs out of food.
Why Do Seeds Travel?
A seed that falls only at its parent's feet must compete with the big plant for light and water. Traveling gives the baby plant a new patch of soil.
Why Is a Forest Quiet, Then Loud?
A forest is full of living sound-makers that clock in at different hours. Midday can feel hushed, while dawn and dusk can roar with birds, frogs, and insects.
Why Do Mushrooms Pop Up After Rain?
The mushroom you see is only the fruit of a fungus. The real fungus is a hidden web in the soil.
Why Do Vines Climb?
A vine is a plant that borrows height. Climbing is cheaper than growing a thick trunk, and height means more sunlight.
Why Is Moss So Soft and Low?
Moss is a tiny plant with no true tall stem and no thick roots. It hugs rock and soil like a soft green cushion.
Why Do Pine Trees Stay Green All Year?
Pine needles are leaves built for winter. They are thin, tough, and waxy, so they can keep making a little food even when other trees are bare.
Why Do Some Plants Have Thorns?
Thorns, spines, and prickles are plant armor. They turn a juicy stem or leaf into a painful snack, so many animals try a different plant.
Why Do Leaves Turn Red and Gold?
In autumn, green chlorophyll fades first. Yellow and orange were hiding underneath the whole time.
Why Do Trees Have Rings Inside?
A ring is one year of new wood. In many climates, a tree grows in a yearly pulse, so you can count the pulses.
Why Do Plants Drink Through Roots?
Roots are the plant's drinking straws. Tiny hairs pull water and minerals from the soil, so the leaves can cook food in the sun.
Why Do Some Flowers Close at Night?
Closing is a nightly shield. Petals fold to protect pollen from dew and cold, and from night visitors the flower does not need.
Why Do Forests Feel Cooler?
A forest is living shade, plus living air conditioning. Leaves block the sun, and they release water vapor that carries heat away.
Why Do Some Plants Eat Bugs?
A few plants live in soggy soil that lacks minerals. Catching a bug is how they grab extra nutrients, especially nitrogen.
Why Do Cactuses Store Water?
A desert can go weeks without rain. A cactus is a living water tank, with a waxy skin that slows leaks and thick stems that hold moisture.
Why Do Leaves Have Veins?
Veins are roads and drinking straws inside a leaf. They carry water in and sugar out, and they keep the soft leaf blade from flopping.
Why Do Trees Sway But Not Snap?
A living trunk is strong and springy. Bending lets wind energy pass through, instead of breaking the wood the way a stiff pole might.
Why Do Forests Need Dead Logs?
A fallen log is not trash. It is a slow-release pantry, a sponge, and an apartment building for fungi, bugs, moss, and new seedlings.
Why Do Earthworms Help Gardens?
Earthworms are living tillers! They eat dead leaves, leave behind rich castings, and dig tunnels that let air and water into packed dirt.
Why Do Woodpeckers Peck Trees?
Pecking is a toolkit! Woodpeckers drum to talk, chip holes to nest, and tap bark to find insect larvae hiding in the wood.
Why Does Frost Paint the Grass?
Frost is dew's frozen cousin! When grass gets colder than freezing, water vapor can turn straight into ice crystals on the blades.
Why Is the Forest Louder at Night?
For many animals, night is rush hour. Frogs, insects, owls, and mammals that hide by day clock in for their night shift.
Why Do Some Flowers Smell Stronger at Night?
Some plants clock their perfume for moths and other night pollinators. Color is harder to see after dark, so scent becomes the billboard.
Why Do Mushrooms Seem to Pop Up Overnight?
The mushroom you see is just the fruit. The real body of the fungus is a hidden web of threads in the wood or soil.
Why Do Some Trees Creak at Night?
Wood is not a silent statue. Wind, cooling air, and branches rubbing together can all make a tree groan.
From Book 5: The Time Expedition (7)
Munch Munch! Why Did Plant-Eaters Have Beaks or Grinders?
Plants can be tough to eat, so plant-eating dinosaurs had special tools. Some had beaks for snipping leaves and stems.
Leaf Prints! Why Do We Find Fossils of Leaves and Wood?
Plants can become fossils too. A leaf can leave a print in soft mud, and buried wood can slowly turn to stone as minerals fill it.
Always Wet! Why Do Rainforests Stay Wet?
Rainforests get a lot of rain, and the warm air holds plenty of moisture. Trees also release water vapor from their leaves, which adds to the damp air.
Ancient Fashion! Why Did People Wear Skins and Plant Fibers?
People needed clothes to stay warm and protected, and they made them from what they could find. That included animal skins and fibers from plants.
Seeds of Change! Why Did Farming Change Everything?
Farming meant people could grow plants and raise animals instead of only searching for food. That let more people stay in one place and store food for later.
Tree Rings! Why Do Rings Count Years?
Many trees grow a new ring each year, and each ring records what that year was like. Wide rings often mean a good year for growing, and narrow rings can mean a harder one.
Ring Around the Tree! Another Look at Tree Ring Time
Tree rings are a natural record of years. Each ring is one year of growth, so counting them can tell a tree's age.
From Book 6: The Ocean Expedition (4)
Why Is a Kelp Forest So Tall?
Giant kelp is a seaweed that races toward the light! It is a kind of algae, not a tree with wood.
Why Do Anemones Look Like Flowers?
An anemone looks like a flower, but it is really an animal! It is a close cousin of coral and jellyfish.
Why Do Christmas-Tree Worms Vanish?
Those little colorful trees on a Christmas-tree worm are really its gills and feeding fans. The worm lives safely in a tube in the coral.
Why Do Scientists Plant Coral?
Scientists grow tiny pieces of coral in nurseries. Then trained teams attach them to damaged reefs, where they can grow into new colonies.
From Book 7: The Weather Expedition (6)
Why Does Dew Sparkle on Grass?
Dew is made of tiny beads of water that appear on grass overnight. At night the grass cools down, and invisible water vapor in the air touches it and turns into liquid droplets.
Why Does Water Drip From Leaves After Rain?
Leaves catch rain like tiny umbrellas, and they hold on to a lot of water. After the rain stops, the stored water slowly slides off in drips.
Why Do Tall Trees and Towers Get Struck More Often?
Lightning often hits the tallest handy point. Tall trees and towers stick up into the part of the sky where the storm's electricity is.
Why Do Leaves Change Color in Autumn?
Leaves change color in autumn because trees stop making green chlorophyll. Shorter days and cooler weather tell trees to get ready for winter.
Why Do Gardens Need Different Planting Months?
Gardens need different planting months because plants need the right mix of warmth, light, and no frost. Every place has its own pattern of seasons, so planting calendars follow local weather.
Why Do Tree Rings and Ice Cores Hold Climate Clues?
Tree rings and ice cores hold climate clues because they store a yearly record of the past. Each year, a tree adds a ring and the ice adds a layer, and both are shaped by that year's weather.
From Book 9: The Food Expedition (6)
Why Does the Fizzy Mix of Baking Soda and Vinegar Get Cold?
The fizzy mix of baking soda and vinegar gets cold because the reaction soaks up heat! As it makes carbon dioxide gas, it pulls warmth from the liquid.
Why Is Fiber in Plants Helpful?
Fiber in plants is helpful because it helps food move through your body and feeds friendly gut microbes! Fiber is the part of plants that your body cannot fully digest, and that is a good thing.
Why Sprout Seeds on a Windowsill?
We sprout seeds on a windowsill to watch a plant wake up! A seed holds a tiny baby plant called an embryo, plus stored food.
Why Is Corn a Seed, a Grain, and a Vegetable Depending on Talk?
Corn can be a seed, a grain, and a vegetable because the words depend on how we use it! Botanically, a corn kernel is a seed.
Why Are Mushrooms Neither Fruits Nor Veggies Exactly?
Mushrooms are not exactly fruits or vegetables because they are fungi! Fungi are their own kingdom of life, separate from plants and animals.
Why Thank Plants at Dinner?
We thank plants at dinner because plants turn sunlight into food! Leaves, roots, seeds, and fruits all come from plants making food through photosynthesis, a word that means putting together with light.
From Book 11: The Animal Expedition (6)
Why Do Leafcutter Ants Farm Fungus?
Leafcutter ants farm fungus because the fungus is their food! The ants cut up leaves, but they don't eat the leaves.
Why Do Leaf-Tailed Geckos Look Like Dead Leaves?
Leaf-tailed geckos look like dead leaves because it helps them hide! They live in the forests of Madagascar.
Why Do Tailorbirds Sew Leaves Into Nests?
Tailorbirds sew leaves into nests so their eggs stay hidden and dry! They live in warm parts of Asia.
Why Do Squirrels Build Leafy Nests High in Trees?
Squirrels build leafy nests high in trees to stay warm, dry, and out of reach! These round nests are called dreys.
Why Do Woodpeckers Carve Nest Holes in Trees?
Woodpeckers carve nest holes in trees because a hole in a trunk is a safe, dry home! It keeps eggs away from most predators.
Why Do Tree Frogs Need Moist Micro-Homes?
Tree frogs need moist micro-homes because their thin skin dries out fast! A micro-home is a tiny damp hideout, like a leaf pocket or a hollow in a tree.
From Book 12: The Volcano Expedition (2)
Why Do Continents Have Deep Roots?
Continents have deep roots, just like an iceberg floating in the sea! Thick, light crust floats on the heavier rock of the mantle.
Why Do Tree Rings Near Volcanoes Tell Stories?
Tree rings near volcanoes tell stories because trees grow a new ring every year. Each ring is a page in the tree's diary, and eruptions can leave marks on those pages.
From Book 13: The Light Expedition (6)
Why Are the Spots of Sunlight Under a Tree Round?
Tiny gaps between leaves work like pinholes. Each gap makes a little picture of the Sun on the ground.
Why Can Bees See Patterns on Flowers That We Cannot?
Bees and many other insects can see ultraviolet light, which humans cannot. Many flowers have patterns that only show up in ultraviolet.
Why Can a Water Drop on a Leaf Work Like a Tiny Lens?
A small drop of water has a smooth, curved top. That shape bends light just like a tiny magnifying lens.
Why Does a Wet Leaf Look Shinier than a Dry One?
A dry leaf has tiny bumps that scatter light, so it looks dull. Water fills in the bumps and makes a smooth, clear layer on top.
Why Do Indoor Plant Lamps Often Look Pink or Purple?
Indoor plant lamps often look pink or purple because they use red and blue light! Plants use those colors the most.
Why Do Some Solar Power Plants Use Hundreds of Mirrors?
Some solar power plants use hundreds of mirrors to gather sunlight! The mirrors tilt to follow the Sun and aim at one spot on a tower.
From Book 14: The Sound Expedition (2)
Why Does Rain Sound Louder on a Metal Roof than on Grass?
A metal roof acts like a giant drum when raindrops land on it! The whole thin sheet vibrates, and the sound spreads out.
Why Can You Hear a Clear Echo in a Canyon but Not in a Forest?
An echo is a sound that bounces off a hard surface and comes back to you! In a canyon, tall flat rock walls send your voice straight back.
From Book 15: The Robot Expedition (2)
Why Do Greenhouse Robots Check Plants One by One?
Greenhouse robots check plants one by one so they can spot problems early! They roll or hang between the rows and use cameras to look at each plant.
How Do Scientists Use Drones to Study Tall Trees and Forest Canopies?
Scientists use small drones to study tall trees because drones can fly right up to the treetops! Tree canopies are full of leaves, branches, and animals, high above the ground.
From Book 16: The Desert Expedition (24)
How Do Plants Survive in Places Where It Almost Never Rains?
Desert plants survive with clever tricks for finding, saving, and waiting for water! Some store water in their stems, some grow long roots, and some wait as tiny seeds.
Why Do Many Desert Plants Have Tiny Leaves or No Leaves at All?
Desert plants have tiny leaves or none at all, because leaves lose water! Water escapes through tiny pores in a leaf, especially in hot, dry air.
Why Do Some Desert Shrubs Send Their Roots Down 50 Feet or More?
Some desert shrubs send roots down 50 feet or more to reach water far below! Deep underground, the soil stays damp long after the surface dries out.
Why Do Some Desert Plants Spread Their Roots Wide but Shallow?
Some desert plants spread their roots wide but shallow to catch rain fast! A desert rain soaks only the top few inches of soil, and it dries quickly.
How Can a Seed Wait for Years Until It Rains?
A desert seed can wait for years, because it has a tough coat and a rain sensor! Chemicals in the coat keep the seed from sprouting too soon.
How Does a Joshua Tree Depend on One Little Moth?
A Joshua tree depends on one little moth, and the moth depends on the tree! It is a partnership where each one helps the other.
Why Do Some Desert Plants Have Fuzzy or Silvery Leaves?
Some desert plants have fuzzy or silvery leaves, because tiny hairs help them stay cool and moist! The hairs slow water loss and bounce sunlight away.
Why Do Some Desert Plants Open Their Pores Only at Night?
Some desert plants open their pores only at night, so they lose less water! Open pores let in air, but they also let water escape.
Why Are Aloe Leaves So Thick and Gel-Filled?
Aloe leaves are thick and gel-filled because they are built to store water! The juicy gel inside holds water for a long time.
Why Do Some Desert Plants Look Like Pebbles?
Some desert plants look like pebbles, so hungry animals walk right past them! They are called living stones, and they grow in southern Africa.
Why Does the Ocotillo Grow Leaves Only After It Rains?
The ocotillo grows leaves only after it rains, so it does not waste water! Most of the year, it looks like a bundle of dead sticks.
How Can a Resurrection Plant Come Back to Life?
A resurrection plant can come back to life, because it only dries out and does not die! It curls into a tight, brown ball and waits.
Why Do So Many Desert Plants Have Thorns or Spines?
Desert plants have thorns and spines because they hold precious water, and animals would eat them! Sharp points make a bite painful, so most animals give up.
What Is the Welwitschia, the Namib Plant That Lives for Centuries?
The welwitschia is a plant from the Namib Desert that can live for centuries! It has just two long, strap-shaped leaves that never stop growing, which is very unusual for a plant.
How Do Desert Plants Avoid Crowding Each Other?
Desert plants avoid crowding because there is not enough water for them to be close together! Each plant needs a big patch of ground to collect rain.
Why Do Some Desert Leaves Stand on Edge Instead of Lying Flat?
Some desert leaves stand on edge or hang down, so they catch less hot sunlight! It is a clever shade trick that works without any shade at all.
Why Do Big Cacti Have Pleated Sides?
Big cacti have pleated sides because the pleats work like an accordion! They let the cactus swell up when it drinks and shrink when the water is used.
How Do Mesquite Trees Make Poor Desert Soil Richer?
Mesquite trees make poor desert soil richer by teaming up with tiny helpers in their roots! Those helpers are bacteria that make plant food from the air.
How Do Animals Help Desert Seeds Spread?
Animals help desert seeds spread by carrying, burying, eating, and dropping them! A seed that is moved to a good spot has a much better chance to grow.
Why Do Many Desert Plants Taste Bitter or Smell Strong?
Many desert plants taste bitter or smell strong, because those are their way to protect themselves! A plant cannot run away from a hungry animal, and its water and food are precious.
What Useful Things Do People Get From Desert Plants?
People get many useful things from desert plants, like food, fiber, oil, and shade! People have used desert plants for thousands of years, and they have learned which ones are safe and helpful.
How Does the Tiny Elf Owl Find a Home in a Cactus?
The tiny elf owl finds a home in a cactus by moving into a hole that a woodpecker made! The hole is cool, safe, and ready to use.
How Do Bats Help Desert Plants?
Bats help desert plants by carrying pollen from flower to flower at night! The bats drink sweet nectar, and pollen from the flowers dusts their fur.
Why Can Palm Trees Grow at an Oasis?
Date palms grow at an oasis because they love hot sunshine, but their roots also need lots of water! At an oasis, water is close to the surface, so the roots can drink.
From Book 18: The Polar Expedition (5)
Why Are There No Tall Trees on the Arctic Tundra?
There are no tall trees on the Arctic tundra because it is too cold, too windy, and the ground is frozen below the surface! So plants stay small and low.
Why Do Plants Grow So Fast in the Arctic Summer?
Plants grow so fast in the Arctic summer because the midnight Sun gives them light almost around the clock! They race to grow before winter comes back.
Why Do Some Arctic Flowers Turn to Follow the Sun?
Some Arctic flowers turn to follow the Sun because their cup-shaped petals act like tiny satellite dishes that gather warmth! This sun tracking is called heliotropism.
Why Do Arctic Bird Cliffs Have Bright Green Grass and Orange Rocks?
Arctic bird cliffs are green and orange because seabirds feed the plants without trying! Their droppings work like fertilizer.
Can a Flower Bloom Again After 30,000 Years Frozen?
Yes! Scientists grew a flower from a fruit that was frozen for about 30,000 years!
From Book 19: The River Expedition (8)
How Can River Plants Bend Without Breaking?
River plants bend without breaking because they are flexible, and the water helps hold them up! They sway with the current instead of fighting it.
How Do Trees Along a Riverbank Help the Animals in the Water?
Trees along a riverbank are green helpers that take care of the animals in the water! They give shade, food, and shelter to fish, insects, frogs, and birds.
Why Are Fallen Trees Good for a River?
A tree that falls into a river becomes a home for lots of animals! It makes shelter and food, and it changes the flow of the water.
How Did Loggers Float Trees Down Rivers?
Long ago, workers floated trees down rivers in a big event called a log drive! Spring floods carried the logs to sawmills.
Why Does Rain Run Off Pavement Faster than It Soaks Into Grass?
Rain runs off pavement faster than it soaks into grass because pavement cannot soak up water! Soil is full of tiny spaces that act like a sponge.
How Do Forests and Wetlands Slow Down a Rising River?
Forests and wetlands slow down a rising river because they work like sponges! They soak up rain and slow the water as it moves.
How Can a Strip of Plants Catch Muddy Runoff Before It Reaches the River?
A strip of plants along a river catches muddy runoff before it reaches the water! It is called a buffer, and it works like nature's filter.
What Is a Rain Garden?
A rain garden is a shallow, planted dip in the ground that collects rain! Instead of rushing into a storm drain, the water soaks in slowly.
From Book 20: The Mountain Expedition (15)
Do Mountains Have Roots?
Yes, in a way, mountains have roots! Earth's crust floats on the softer rock below it, like an iceberg in water.
Why Do Trees Get Short and Twisted Near the Top?
Near the treeline, icy winds and blowing ice crystals scour off buds and branches on the windy side! Trees survive by staying low and growing sideways.
What Is a Montane Forest?
Montane means of the mountains! A montane forest is the zone where trees grow tall and thick, usually evergreens like fir, pine, and spruce.
Why Are Mountain Evergreen Trees Shaped Like Cones?
Mountain evergreens are shaped like cones because the shape helps them handle heavy snow! Pine, spruce, and fir trees often have a narrow cone shape.
Why Do Mountain Meadows Burst Into Flowers All at Once?
Mountain meadows burst into flowers all at once because the summer is so short! When the snow melts, plants race to bloom, make seeds, and store food before cold weather returns.
What Is the Oldest Tree on a Mountain?
The oldest tree on a mountain is the bristlecone pine! Bristlecone pines high in the White Mountains of California can live almost 5,000 years.
How Did a Famous Explorer Find Out That Plants Live in Bands on Mountains?
A German scientist named Alexander von Humboldt discovered that plants live in bands on mountains! In 1802, he visited the Andes and studied the plants as he went uphill.
Why Are Some Mountain Plants and Animals Moving to Higher Ground?
Some mountain plants and animals are moving to higher ground because the climate is getting warmer! When it warms, the cool zone shifts uphill.
What Are Cushion Plants?
Cushion plants are tiny alpine plants that grow in round, tight mounds like pillows! They look soft and cozy, and they really are cozy inside.
Why Are Alpine Flowers So Bright for Such Little Plants?
Alpine flowers are bright because they need to be noticed! The plants are small, but their flowers can be big and brightly colored.
Why Do Some Alpine Grasses Grow Baby Plants Instead of Seeds?
Some alpine grasses grow baby plants instead of seeds because summers up high are short and cold! Seeds need time to ripen, and sometimes there just is not enough warm weather.
How Can a Flower Bloom Through Snow?
A flower can bloom through snow because it gets a head start under the snow! Some alpine plants store food in underground bulbs all year long.
Why Do Flies Matter So Much to High-Mountain Flowers?
Flies matter so much to high-mountain flowers because they are the main visitors! At high altitudes, there are fewer bees, but there are plenty of flies.
How Does a Bird Help Plant Mountain Forests?
A bird called Clark's nutcracker helps plant mountain forests! It hides seeds in the ground, and some are never found again.
Why Do Some Mountain Forests Have Bare Stripes?
Some mountain forests have long, bare stripes running through them. These stripes are avalanche paths, where snow slides down often and clears away the trees.
From Book 21: The Magnet Expedition (1)
From Book 22: The Energy Expedition (8)
How Does a Leaf Turn Sunshine Into Food?
A green leaf is a tiny food factory. It runs on sunshine!
Why Do Ecosystems Have So Many More Plants than Meat-Eaters?
A meadow has thousands of grasshoppers. But it has only a few hawks.
How Do Plants Store the Energy They Make?
Plants make sugar from sunshine. But they do not use it all at once.
How Does a Power Plant Make Electricity for a Whole Town?
A power plant makes electricity for a whole town. The secret is a spinning machine.
Why Do Many Power Plants Burn Fuels Like Coal and Gas?
Many power plants burn coal, oil, or natural gas. It is a simple way to get a lot of heat.
What Is Nuclear Energy, and How Does a Power Plant Use It?
Nuclear power plants do not burn anything. They get their heat by splitting atoms.
Why Do Some Power Plants Have Giant Cooling Towers?
Some power plants have giant towers that look like huge vases. White clouds float up out of them.
How Can Trees Around a House Save Energy?
Trees can work like free air conditioners for a house. They also block cold winter wind.
From Book 23: The Flight Expedition (1)
From Book 24: The Underground Expedition (29)
What is leaf litter, and what happens to it?
Leaf litter is the loose layer of fallen leaves, twigs, and bits of bark on the forest floor. It protects the soil, keeps it moist, and shelters many small animals.
What jobs do roots do for a plant?
Roots have several jobs. They anchor the plant so wind and rain don't knock it over.
How do roots sense where gravity is pulling?
Roots grow downward because of gravity. In the tip of each root are tiny, heavy grains called statoliths that settle to the low side of the cells.
How do roots find water in the soil?
Roots can sense moisture. In drier soil, the tips bend toward the wetter side, which is called hydrotropism.
What are root hairs, and why do roots have so many?
Root hairs are tiny threadlike growths from a root's outer cells. They look like fuzz and are too small to see easily.
Why do roots grow around rocks instead of through them?
A root tip is soft and cannot push through solid stone. When it touches a rock, it feels the pressure and bends away, growing along the easiest path toward soil that has water and air.
What is the difference between a taproot and fibrous roots?
A taproot is a single thick main root that goes straight down, like a carrot or a dandelion. It can reach deep water and store food.
Which vegetables are really roots?
Carrots, beets, radishes, turnips, parsnips, and sweet potatoes are all storage roots. The plant stores sugar and starch in them to use later, such as when it flowers.
How far do tree roots spread?
Most tree roots are surprisingly shallow. The majority grow in the top foot or two of soil, where there is air, water, and nutrients.
Why do tree roots sometimes lift sidewalks and crack pipes?
Roots grow where air and water are available, often right under the pavement. As they get thicker, they push up on the slab above them and can lift it.
How do roots hold a hillside together?
Roots work like thousands of tiny ropes tying the soil together. They make a net that holds soil in place and helps rainwater soak in instead of rushing downhill.
How long could the roots of one small plant stretch?
In the 1930s, a scientist carefully washed the soil from one winter rye plant that had grown for four months. He measured over 380 miles of root, and billions of tiny root hairs.
What is a mycorrhiza, the partnership between roots and fungus?
A mycorrhiza is a team-up between a plant root and a fungus. The fungus's threads wrap around or enter the root and spread far into the soil, reaching water and minerals like phosphorus that roots cannot reach.
What are the thin threads of a fungus that spread underground?
The main body of most fungi is a mass of super-thin threads called mycelium. Each thread is much thinner than a hair, but together they form a web that spreads through soil, wood, and leaves.
Do trees really share food through underground fungus networks?
In some experiments, scientists, including Suzanne Simard in British Columbia, have found that carbon can move between trees through fungus threads. This idea is sometimes called the wood wide web.
How big can a single fungus grow?
One of the largest living things is a honey fungus in an Oregon forest. Its threads spread under the soil across about 2,400 acres, about as big as 1,800 football fields, and it has been growing for thousands of years.
Why do mushrooms sometimes grow in a circle called a fairy ring?
A fairy ring is a circle of mushrooms in a lawn or forest. It starts from one spot where a fungus grows underground from a single spore.
How do bean and pea roots get help from bacteria?
Plants need nitrogen to grow, and the air is full of it, but plants can't use it as a gas. Beans, peas, and clover have little lumps on their roots called nodules, filled with helpful bacteria.
Is a potato a root?
No, a potato is a tuber, a swollen underground stem that stores food for the plant. The little dents called eyes are buds that can sprout into new plants.
Why is it so hard to dig up grass that spreads underground?
Many grasses have underground stems called rhizomes, which grow sideways below the surface. Along them, new shoots pop up.
How can a forest of trees be one single living thing?
Quaking aspens can grow new trunks from a single wide root system. A forest in Utah called Pando has about 47,000 trunks, all genetically identical and connected underground.
Why can a cut-down tree stump grow new shoots?
The roots still hold lots of stored food. If the stump and roots are alive, they can send up new shoots from buds near the base.
Why do prairie grasses have roots deeper than the plants are tall?
Prairie grasses like big bluestem can have roots reaching 10 feet or more underground, while the tops reach only 6 feet or so. Deep roots find water during dry spells, and they hold soil in the wind.
What is the rhizosphere, the busy zone around a root?
The rhizosphere is the narrow zone of soil, only a few millimeters thick, around each root. Roots leak sugars and other chemicals into it, which attract bacteria and fungi.
How can scientists watch roots grow underground?
Scientists use clear tubes, called minirhizotrons, put into the soil with tiny cameras inside. Some research stations have underground rooms with glass walls so that researchers can see roots through the window.
Why do root cellars keep food fresh?
A root cellar is a room dug into the ground or a hillside. A few feet down, the temperature stays cool and steady all year, even when the weather above is freezing or hot.
Why is there a seed vault inside a frozen mountain?
The Svalbard Global Seed Vault is a safe storage place dug into a mountain in the Arctic. It keeps backup copies of seeds from crops from around the world, in case a farm or seed bank loses its seeds.
Why do ghostly lines show up in dry grass or crops?
Buried stone walls or roads make the soil shallow above them, so plants dry out faster and turn yellow. Buried ditches hold more water, so plants above them grow greener and taller.
Why can squished soil make it hard for plants to grow?
Heavy machines, feet, and tires press soil grains tightly together and squeeze out the air gaps. Roots can't push through hard soil, water runs off instead of soaking in, and soil animals have no room to move.