What Exactly Is Energy?
Energy is the ability to make something change or move. It is what lets a ball roll, a plant grow, a bulb glow, and a kid run. You cannot hold it in your hand, but you can see what it does!
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How Can You Tell Energy Is There When You Can’t See It?
Energy is never seen on its own. It is a bit like wind, which you only see in the leaves it moves. So how do we know energy is there?
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What Kinds of Energy Are There?
Energy comes in many forms. Moving things, hot things, light, sound, and electricity are all energy. Let's meet the family! All the forms of energy can change from one into another, and that is what makes things happen.
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How Is Stored Energy Different From Moving Energy?
Stored energy is energy that is waiting to be used. Moving energy is energy that is happening right now. And one can turn into the other!
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Why Can Energy Never Be Made or Destroyed?
Scientists have tested this for more than a hundred and fifty years. Energy is never made from nothing, and it never disappears. It only changes form!
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Where Does a Ball’s Energy Go When It Stops Rolling?
A rolling ball slowly slows down and stops. But the ball's energy does not simply disappear. So where does it go? Friction always turns some motion energy into heat.
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What Does It Mean to “Use Up” Energy?
People often say they use up energy. But energy never really vanishes. So what are we really using up? Energy does not vanish when a battery runs flat.
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Why Does a Stretched Rubber Band Hold Energy?
A stretched rubber band can fling a paper ball across a room. That is because stretching stores energy. A stretched rubber band stores energy just like a coiled spring.
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Why Does a Book on a High Shelf Hold Energy?
A book sitting on a high shelf looks very still. But it is secretly holding energy! Here is why. The higher the shelf, the more energy the book stores.
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What Is the Energy Hiding in Food, Fuel, and Batteries?
Food, fuel, and batteries all have energy hiding inside. It is called chemical energy. A single spoonful of sugar holds enough chemical energy for a short walk.
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Why Do Scientists Call Heat Energy on the Move?
Heat is energy that moves from a warmer thing to a cooler thing. That is why scientists call it energy on the move. Let's watch it travel!
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How Does Energy Change From One Form Into Another?
Energy changes form whenever something happens. A toaster, a battery, a plant, and your muscles all do it. Let's follow the changes!
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How Can You Follow Energy From the Sun to Your Toast?
The toast on your plate holds energy that started in the Sun. Sunlight traveled a very long way to get there. Let's follow the whole path!
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Why Do Machines Waste Some Energy?
In every machine, some energy turns into heat that nobody wanted. Engineers call that wasted energy. A gasoline car engine turns only about a quarter of the fuel's energy into motion.
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What Does “Work” Mean in Science?
In everyday talk, work means a job or a task. But in science, work has a special meaning. In science, work happens only when a force moves something.
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What Is Power, and How Is It Different From Energy?
Energy is the total amount, and power is how fast energy is used. Two people can use the same energy at different speeds. Let's compare them!
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How Do We Count Energy?
Energy can be counted with several different units. Scientists, food labels, and electric companies each choose their own. Let's compare them!
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How Did James Joule Show That Motion Can Turn Into Heat?
Long ago, a scientist named James Joule had a big question. Could motion turn into heat? He built a clever machine to find out! James Joule did his famous work in the 1840s.
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Do Rocks and Mountains Have Energy?
A rock sitting on the ground looks completely still. But does it have energy? The answer is yes! Even a cold rock holds lots of thermal energy because its atoms never stop moving.
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Why Do People Say “Save Energy” If Energy Never Disappears?
Energy never disappears, so why do people say save energy? It is because useful energy can run out. Energy is never destroyed, but the useful kind can run out.
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What Happens to Energy When Two Things Bump?
Energy can hop from one thing to another when they bump. A moving ball, a warm hand, and even a sound all pass it along. Energy is always handed on!
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Why Does It Take Energy to Make Something Move, Even a Little?
A still object likes to stay still. To get it moving, you must give it some energy. Even a small push counts! A big truck needs a lot more energy than a bike to get going.
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Is There Energy Inside Atoms?
Atoms are unbelievably tiny. But there is energy inside them in more than one way. Let's peek inside! Atoms hold energy in many different ways.
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Can a Wave Carry Energy Without Carrying Stuff Along?
A wave carries energy from one place to another. But the stuff it moves through barely travels at all. A duck on a lake bobs up and down while the waves roll past.
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Why Can’t We Build a Machine That Runs Forever?
Imagine a machine that runs forever with no fuel at all. People have dreamed about it for hundreds of years. But it can never work!
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What Is Kinetic Energy, the Energy of Motion?
Kinetic energy is the energy of motion. Anything that moves has it. The word kinetic comes from a Greek word that means moving. Anything that moves has kinetic energy.
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Why Does a Diver on a High Board Hold Potential Energy?
A diver on a high board is standing still. But she is holding a lot of energy! It is called potential energy. Potential energy can be stored for years and released in a second.
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Why Does Speed Matter So Much for Moving Energy?
A moving thing's energy grows fast with its speed. Double the speed, and the energy does not just double. It becomes four times bigger!
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Why Does a Heavy Truck Have So Much More Moving Energy than a Bicycle?
A heavy truck and a bicycle can roll at the same speed. But the truck carries far more moving energy. A fully loaded truck can weigh twenty times more than a family car.
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How Does a Roller Coaster Trade Height for Speed?
A roller coaster climbs a big hill very slowly. Then it zooms down at top speed! The tallest hill on many coasters is right at the start.
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Why Does a Pendulum Swing Back and Forth?
A pendulum is just a weight hanging from a string. Yet it swings back and forth in a steady rhythm. A pendulum takes almost the same time for each swing, no matter how wide the swing.
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Why Does a Ball Speed Up Faster on a Steeper Hill?
A ball rolling down a steep hill speeds up fast. On a gentle hill, it speeds up slowly. Galileo rolled balls down ramps about four hundred years ago to study how things speed up.
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Where Does a Squashed Spring’s Stored Energy Go When You Let Go?
Squeezing or stretching a spring puts energy into it. Let go, and it springs right back! Where does that stored energy go? Springs inside a car help smooth out bumps by squeezing and springing back.
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How Does a Wind-Up Toy Store Energy?
A wind-up toy walks, hops, or rolls without a battery. The secret is a twisted metal spring inside. Let's open it up! Wind-up clocks and music boxes have used springs for hundreds of years.
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Why Does Falling From Higher Up Hurt More?
Falling from higher up hurts more than falling from low. Energy is the reason. Soft surfaces spread the stopping out over a longer time, which lowers the force.
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How Does a Moving Bowling Ball Pass Energy to the Pins?
A rolling bowling ball is full of moving energy. When it crashes into the pins, they fly everywhere. Let's follow the energy! Pins are lighter than the ball, so they speed up when they are hit.
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Why Can One Domino Knock Over a Whole Row?
Line up lots of dominoes and tip the first one. Click, click, click, they all fall down! How does one domino topple them all? Each domino can topple one about one and a half times its size.
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Where Does the Energy Come From When You Jump?
When you jump, you go up in the air all by yourself. Where does the energy for that come from? Your muscles and your lunch! On the Moon, the same jump would take you about six times higher.
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How Does a Toy Catapult Launch Things?
A toy catapult can toss a soft pom-pom across the room. It does that with stored energy. Let's build the idea! The arm of a catapult is a lever, which makes the throw faster.
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How Does a Cyclist Use Energy to Climb a Hill and Then Coast?
Pedaling uphill is hard work. But coasting down feels like magic. Let's follow the energy! Coasting downhill can be faster than pedaling on flat ground.
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Where Does the Energy Go When Bike Brakes Stop You?
When you squeeze bike brakes, you slow down quickly. But the moving energy does not just vanish. It turns into something else! The faster you go, the more heat the brakes have to create to stop you.
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How Do Electric and Hybrid Cars Save Energy While Braking?
Most brakes turn a car's moving energy into wasted heat. But electric and hybrid cars have a clever trick. They save the energy to use again!
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How Does a Flywheel Store Energy?
A flywheel is just a heavy wheel that spins. Once it gets going, it just keeps on spinning. That makes it a great energy store! Some old buses ran on large spinning flywheels.
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How Does a Hand-Crank Flashlight Work Without Batteries?
A hand-crank flashlight has no batteries to replace. You just turn the crank, and the light comes on. How does that work? Hand-crank radios and chargers use the same idea.
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How Does a Yo-Yo Store Spinning Energy?
A yo-yo drops, spins, and climbs right back up your hand. The secret is spinning energy. Let's watch it work! A well-made yo-yo can sleep at the end of the string, spinning for many seconds.
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How Does a Balloon Rocket Use Stored Energy?
A blown-up balloon holds energy in the air inside it. Let it go, and it zooms around the room! Let's learn the secret. A balloon filled with more air flies farther.
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Why Does a Pogo Stick Make You Bounce?
A pogo stick lets you bounce up and down like a kangaroo. The secret is a strong spring. Kangaroos have springy tendons in their legs that store energy for each hop.
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How Does a Zipline Turn Height Into Speed?
A zipline sends riders gliding along a cable. They start high and end low. Longer ziplines can have a drop of hundreds of feet. Height at the start turns into speed on the way down.
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Why Is a Heavy Box Harder to Push than an Empty One?
A heavy box is harder to push than an empty one. You may think it is only because it weighs more. But friction has a big part in it!
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How Do Helmets and Padding Soak Up Moving Energy?
A helmet has soft foam inside. When something hits it, the foam squashes. That squashing protects your head! Padding spreads the force of an impact over a wider area.
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How Does the Sun’s Energy Cross Empty Space to Reach Us?
The space between the Sun and Earth is almost completely empty. There is no air to carry heat across it. So how does sunshine get here?
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What Makes the Sun Give Off So Much Energy?
The Sun gives off an amazing amount of energy every single second. Where does it all come from? Deep inside, something powerful is happening!
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How Much of the Sun’s Energy Does Earth Actually Catch?
The Sun sends its light out in every direction. Earth is a small target, far away. So how much do we actually catch? Earth catches only about one two-billionth of the Sun's energy.
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How Can Heat Travel From Place to Place?
Heat does not stay in one place. It moves in three different ways. Let's learn all three! Radiation is the only way heat can travel through empty space.
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Which Holds More Heat: a Cup of Hot Tea or a Tub of Warm Water?
Which holds more heat, a small cup of hot tea or a big tub of warm water? Most people guess the tea. The real answer may surprise you!
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How Does a Blanket Keep You Warm If It Makes No Heat?
A blanket feels so warm and cozy. But a blanket makes no heat at all! So how does it keep you warm? Fluffy blankets trap more air and keep you warmer than thin ones.
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How Does a Leaf Turn Sunshine Into Food?
A green leaf is a tiny food factory. It runs on sunshine! A leaf stores only a few percent of the sunlight that hits it. The sugar stores that energy as chemical energy.
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How Is a Solar Water Heater Different From a Solar Panel?
Rooftops can use the Sun in two different ways. One makes hot water, and the other makes electricity. Many warm countries have solar water heaters on rooftops.
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What Is Infrared Light?
Beyond the red light you can see, there is another kind of light. Your eyes cannot see it. But your skin can feel it! Some snakes can sense infrared light from warm animals.
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Why Does a Parked Car Get So Hot with the Windows Closed?
A parked car can get dangerously hot, even on a mild day. Sunlight gets in easily. But the heat has trouble getting out! On a warm day, a closed car can heat up by twenty degrees Fahrenheit in ten minutes.
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Why Do Very Hot Things Glow?
When something gets hot enough, it begins to glow. The hotter it gets, the more the color changes. Let's watch the colors climb! The wire in an old light bulb reaches about forty-five hundred degrees Fahrenheit.
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Why Does Sand Heat Up Faster than Water?
On a sunny beach, the sand feels scorching hot. But the water feels cool, even after the same hours of sun. Why do they heat up so differently?
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How Does the Sun’s Energy Keep Water Moving Around the Planet?
The Sun does not only light our days. It also keeps water moving around the whole planet. Let's follow a drop on its trip! Every day, the Sun lifts enough water into the air to fill billions of bathtubs.
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What Invisible Rays Does the Sun Send Us?
Sunlight is more than the light we can see. It also carries invisible rays. Some feel warm, and some can hurt! UV light can pass through clouds, so you can burn on a cloudy day.
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How Much Power Does Sunshine Bring to One Square Meter?
Sunshine brings real power to the ground. Let's measure how much lands on one square meter. A square meter is about the size of a small table top.
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How Did People Long Ago Put Sunshine to Work?
People have used the Sun's energy for thousands of years. Long before electric power, they put sunshine to work. Remember, sun-dried bricks called adobe are still used in warm, dry places.
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How Much Power Does a Solar Panel Lose When Clouds Roll In?
Solar panels love sunshine. But clouds sometimes roll in and cover the sky. So what happens to the power? Some countries with cloudy weather still use lots of solar power.
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How Does a Thermos Keep Soup Warm?
A thermos keeps soup hot for hours. It can also keep a cold drink cold. The thermos was invented in the 1890s by a scientist named James Dewar.
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How Does a Hot-Water Radiator Warm a Room?
A radiator can warm a whole room. It does it without any fan or blowing. A radiator heats a room mostly by moving warm air around.
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What Happens to Light When Something Swallows It?
When light hits something, it can bounce off or get swallowed. Swallowed light turns into heat. That is why a black shirt feels so warm in the sun!
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What Are the Tiny Packets of Energy in a Sunbeam?
Light travels as a wave. But it also comes in tiny packets of energy called photons. Let's meet them! A single light bulb sends out trillions upon trillions of photons every second.
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How Much Heat Does a Person Give Off?
Sitting still, your body is giving off heat. In fact, you are about as warm as a bright light bulb! A group of twenty people in a room gives off about as much heat as twenty light bulbs.
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How Hot Is the Sun’s Surface, and How Hot Is Its Core?
The Sun is a ball of glowing gas. But different parts of it have wildly different temperatures. The Sun's core is about twenty-seven hundred times hotter than its surface.
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How Do Astronauts Keep Cool in Space Where There Is No Air?
In space, there is no air at all. That means no breeze to cool an astronaut. So how do they keep from overheating? Parts of a spacecraft in the Sun can get hot, while parts in the shade become very cold.
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Why Doesn’t Earth Keep Getting Hotter If the Sun Keeps Sending Energy?
The Sun keeps sending energy to Earth every day. So why doesn't our planet keep getting hotter and hotter? The answer is balance! Without any air, Earth would be much colder than it is.
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How Do Scientists Find Out How Much Energy Is in a Peanut?
How could anyone measure the energy in a peanut? Scientists use a clever device. It is called a calorimeter! Peanuts are rich in fat, which stores lots of energy.
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Why Is the Calorie on a Food Label Spelled with a Capital C?
Food labels list Calories. You may have noticed that the word starts with a capital C. That is not a mistake! Many countries use kilojoules on food labels instead of Calories.
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How Does Your Body Get Energy Out of Food?
Food has energy locked inside. Your body has to unlock it. The adventure starts in your mouth! Remember, your body can store extra glucose in your liver and muscles for later.
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How Do Your Cells Burn Food Without Fire?
Your cells burn food, but there is no flame. There is no smoke or fire at all. So how do they do it? Mitochondria are often called the power plants of the cell.
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Why Does Your Body Make Its Own Heat?
Your body makes its own heat. That is why you stay warm even when it is chilly outside. Let's learn how! Your brain, liver, and muscles make most of your heat.
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How Do Muscles Use Food Energy to Move?
Every time you lift a spoon or kick a ball, your muscles are working. And muscles run on food energy. Muscles use energy even when you sit still, just less of it.
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Why Do Small Animals Eat So Much for Their Size?
A tiny shrew eats almost all day long. An elephant eats a lot too, but far less for its size. Why do small animals eat so much? A hummingbird's heart can beat over a thousand times a minute.
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Why Do Reptiles Need Less Food than Mammals?
A lizard sunbathes on a warm rock. Snakes can go weeks between meals. Why do reptiles eat so much less than mammals? A lizard may need about a tenth of the food a mammal of the same size needs.
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Where Does Energy Go as It Moves Up a Food Chain?
A rabbit eats grass, and a fox eats the rabbit. But energy gets smaller at every step. This is called the ten percent rule. Animals use most of their energy to move and stay warm.
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Why Do Ecosystems Have So Many More Plants than Meat-Eaters?
A meadow has thousands of grasshoppers. But it has only a few hawks. Energy is the reason! A large wild cat may need hundreds of square miles of land to find enough food.
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How Do Plants Store the Energy They Make?
Plants make sugar from sunshine. But they do not use it all at once. They save some for later! Rice, wheat, and corn are seeds packed with starch.
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What Makes Fat Such a Good Energy Bank?
Bears, birds, and many other animals pack on fat. They do it before winter or a long trip. Fat is a super energy bank! A gram of fat holds about nine Calories, while a gram of sugar holds about four.
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How Does Hibernating Save Energy?
In winter, food is hard to find. Some animals just go to sleep for months. That trick is called hibernation! A hibernating ground squirrel's heart may beat only a few times a minute.
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What Is Metabolism?
Even when you are fast asleep, your body is busy. All the chemistry that keeps you going has a name. It is called metabolism! Remember, even when you rest, your body uses energy to keep your heart beating and your lungs breathing.
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Where Does the Energy in Coal and Oil Come From?
Coal and oil are burned to make power. But where did their energy come from in the first place? The answer goes back millions of years!
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Why Does Burning Release Stored Energy?
Fire is amazing and dangerous. Fuels like wood and gasoline hold lots of energy inside them. Burning is how they let it out! The leftovers from burning are mainly water vapor and carbon dioxide.
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Why Do Liquid Fuels Pack So Much Energy?
A little liquid fuel can carry a huge amount of energy. Think of how far a tank of gasoline can take a car. One gallon of gasoline holds about as much energy as a hundred-watt bulb uses in two weeks.
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How Does a Car Engine Turn Fuel Into Motion?
Under a car's hood, small explosions happen again and again. They turn fuel into motion. Let's follow the steps! A typical car engine has four to eight cylinders.
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What Is Biofuel?
Some fuel does not come from deep underground. It comes from plants that are growing right now. That is called biofuel! Remember, some buses and ships run on biodiesel.
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How Did People First Use Wood to Cook and Stay Warm?
People have burned wood for a very long time. They used it for cooking, for light, and for warmth. Wood holds energy from sunlight!
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How Can Rotting Food Scraps Make Fuel?
Banana peels and leftover scraps usually end up as trash. But rotting food can be turned into fuel! Remember, methane is the main part of natural gas.
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How Can an Eel’s Body Make Electric Shocks?
An electric eel can give a real jolt. It is not a magic power. It is a clever body made of tiny batteries! A big electric eel can make over six hundred volts.
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Why Can a Cheetah Sprint Fast but Not for Long?
A cheetah is the fastest land animal on Earth. But it cannot run that fast for very long. Energy is the reason! A cheetah may need half an hour to recover after a sprint.
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Why Do Migrating Birds Eat So Much Before a Long Trip?
Some birds fly across whole oceans without stopping to eat. That takes a lot of fuel. So they fill up before they go! Fat is the best fuel for long flights because it holds so much energy for its weight.
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How Do Deep-Sea Animals Get by with So Little Food?
The deep ocean is dark and cold. No sunlight reaches it, so no plants grow. So how do animals down there get by? Some deep-sea fish have stomachs that stretch to hold meals larger than themselves.
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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. Remember, a big power plant can make enough electricity for hundreds of thousands of homes.
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What Is the Power Grid?
Electricity travels a long way to reach your home. It rides along a giant network of wires. It is called the power grid! The North American power grid is one of the largest machines ever built.
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Why Do Long-Distance Power Lines Use Such High Voltage?
Big power lines carry electricity over long distances. They use very high voltage to do it. Let's learn why! Some long power lines carry hundreds of thousands of volts.
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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. But there are good and bad sides. Natural gas power plants can start up faster than many other kinds.
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What Makes an Energy Source Renewable?
Some energy sources keep coming back. Others run out. What makes the difference? The Sun delivers about as much energy to Earth in one hour as people use in a year.
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How Does a Wind Turbine Turn Wind Into Electricity?
A giant wind turbine looks like a big pinwheel. It makes electricity from the wind. The tip of a big turbine blade can move over a hundred miles an hour, even though the blades look slow.
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Why Do Wind Farms Put Their Turbines So High Up?
Wind farms put their turbines way up high. They use tall towers and very long blades. There is a good reason! A single large turbine can power over a thousand homes.
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How Do Rooftop Solar Panels Share Power with the Grid?
Solar panels on a roof can power a home. But that is not all they do. They can also share power with everyone else! Some homes get credit on their bills for the power they send out.
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How Does a Tidal Power Station Use the Ocean?
The ocean rises and falls twice every day. That is the tide, and it has a lot of energy. Remember, a tidal station in France has been making electricity since nineteen sixty-six.
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How Can Ocean Waves Make Electricity?
Ocean waves never stop moving. That motion is energy. Can we turn it into electricity? Waves hold more energy during storms, but machines must survive them.
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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. A tiny pellet of uranium fuel holds as much energy as a ton of coal.
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What Happens to Solar and Wind Power When the Sun Sets or the Wind Stops?
Solar panels make no power at night. Wind turbines slow down when the air is calm. So how do we keep the lights on? Wind is often stronger at night, while solar is strongest at noon, so they can balance each other.
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How Can We Store Extra Electricity?
Electricity is very hard to store directly. So we change it into another form of energy. Then we change it back when we need it! The biggest batteries on grids can fill several football fields.
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How Does Pumped Storage Work Like a Giant Water Battery?
Imagine a giant battery made of water. It uses two lakes, one high and one low. That is pumped storage! Some pumped storage plants can run for many hours at a time.
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What Is a Kilowatt-Hour on an Electricity Bill?
Your family's electricity bill has a strange unit on it. It says kilowatt-hours. Let's decode it! A kilowatt-hour is the same as three point six million joules.
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Why Does the Electricity in a Town Sometimes Go Out?
Sometimes the lights go out all at once. It can feel a bit spooky. A closed fridge keeps food cold for several hours without power.
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How Do Solar Lamps and Small Grids Bring Light to Faraway Places?
Some villages are far from any power line. Still, they can have light at night. A small solar lantern does the job! A good solar lantern can run for many hours on one day's charge.
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How Is an Electric Car Charged, and Where Does That Energy Come From?
An electric car has no gas tank. It runs on a big battery instead. But where does that energy come from? Electric cars can recover energy when braking.
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Can Hydrogen Be a Clean Fuel?
Hydrogen is a gas that can be a fuel. When it is used in a special device, the only leftover is water. Hydrogen is the most common element in the universe.
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How Much Electricity Can You Make by Pedaling?
Could you power a light bulb with your own legs? A pedal generator can find out! It would take many people pedaling at once to power a toaster.
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Why Do Solar Panels in Canada Face South?
Rooftop solar panels in Canada usually face south. That is not random. It all comes from where the Sun is in the sky. In the summer, the Sun climbs higher, so a flatter panel works better.
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What Is That Gray Can on the Power Pole?
Have you ever noticed a gray can on a power pole? It is not a trash can or a light. It does a very important job! A transformer has no moving parts.
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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. What are those towers doing? Cooling towers can be taller than a thirty-story building.
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Why Does Electricity Use Go Up in the Evening?
Every evening, people all come home at the same time. They flip on lights, cook dinner, and watch TV. That makes electricity use shoot up!
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What Is the Trade-Off with Each Energy Source?
Every energy source has good points. And every one has challenges too. Let's weigh them! No energy source is perfect, so engineers look for balance.
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What Does Energy Efficiency Mean?
Two light bulbs can glow just as bright. But one can use much less electricity. That is called energy efficiency! An LED bulb can use about one-sixth the electricity of an old-style bulb for the same light.
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What Do Energy Star and EnerGuide Labels Tell Us?
Fridges and washers often wear special labels. These labels tell you how much energy a machine uses. Let's learn to read them! Washing machines have become far more efficient than ones from thirty years ago.
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Why Do Some Devices Use Power Even When They Are Turned Off?
Your TV looks like it is off. But a tiny red light is still glowing. Is it still using power? Standby power can add up to a noticeable share of a home's electricity use.
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Why Do Windows Let So Much Heat Escape in Winter?
In winter, warmth tries to sneak out of your house. Windows are one of its favorite exits. Triple-pane windows are common in very cold places.
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How Does Insulation Keep a House Cozy?
A cozy house in winter needs a warm blanket in the walls. It is made of tiny pockets of trapped air. It is called insulation! A wool sweater works like insulation for your body.
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How Does a Thermostat Know When to Turn the Heat On?
A thermostat is like a little brain for your heating. It keeps your home at just the right temperature. How does it know when to switch on?
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How Does a Heat Pump Move Heat Instead of Making It?
A heat pump does not make heat. It moves heat from one place to another. That is a clever trick! A heat pump can warm a home even when it is well below freezing outside.
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Why Does Hanging Laundry Outside Save Energy?
A clothes dryer uses a lot of energy. A clothesline uses almost none at all. The Sun and the wind do the work! Dryers are one of the biggest energy users among household appliances.
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What Happens If the Fridge Door Stays Open?
What if the fridge door stays open? Cold air rushes out into the kitchen. A fridge's door seal is a strip of magnets that holds it tightly closed.
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Why Does Putting a Lid on a Pot Save Energy?
Cooking with the lid off lets heat slip away. Putting the lid on is an easy energy saver. Here is why! A pressure cooker uses a tight lid to cook food faster.
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Does Taking a Shorter Shower Really Save Energy?
A shower feels wonderful on a cold morning. But heating all that water takes lots of energy. So does a shorter shower really help?
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How Can Trees Around a House Save Energy?
Trees can work like free air conditioners for a house. They also block cold winter wind. The right tree in the right place makes a big difference!
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What Is Passive Solar Design?
Some buildings are designed to catch the Sun's free heat. They do it with no machines at all. That is called passive solar design!
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Is Biking More Energy-Efficient than Driving?
A person on a bike zooms along using only muscles. A car burns lots of fuel to go the same distance. Which one is more efficient? A bicycle is often called the most efficient way people have ever invented to travel.
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How Can You Find Drafts in Your Home?
Drafts are sneaky little leaks of air in your home. Cold air gets in and warm air gets out. Let's go find them! Remember, even small cracks can add up to the size of an open window.
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Which Energy-Saving Habits Matter Most?
Some energy-saving habits save more than others. Little choices can add up! Remember, switching to LED bulbs is one of the easiest savings.
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How Do Motion-Sensor Lights Save Energy?
Some lights switch on all by themselves when you walk by. They are called motion-sensor lights. How do they know you are there? Some sensors can tell when a room is empty and switch the lights off.
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Why Does a Phone Charger Feel Warm?
Touch a phone charger, and it feels a bit warm. That warmth tells a secret. Some energy is escaping! More efficient chargers waste less heat.
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Why Does Recycling an Aluminum Can Save Energy?
A used soda can goes in the recycling bin. That little act saves a surprising amount of energy. The energy saved by recycling one can could run a TV for a few hours.
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What New Energy Ideas Are Scientists Testing?
Scientists and engineers never stop testing new ideas. Some might power our world someday. Let's peek into the lab! Remember, some experimental solar cells are thin and bendy like plastic.
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How Can Your Class Run an Energy-Saving Project?
Your class can become a team of energy detectives. You can find wasted energy at school. And then you can fix it! Many schools have saved real money with student energy teams.
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Can Footsteps on a Special Floor Make Electricity?
Could your footsteps make electricity? Special floor tiles say yes, a little. Let's step into the idea! Floor tiles like these have been tested in train stations and playgrounds.
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Which Things in a Home Use the Most Energy?
Your home uses energy in many ways. Some things use much more than others. Which ones are the big users? A fridge runs all day and night, so it uses lots of energy over a year.
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