PresentacióN1 Energy For Kids For ExamplePresentation Transcript
Energy is special.
There's lots of it about and it's very useful.
Why? What's so special?
Here's just a few reasons:
it lets me swim fast and catch my fish
it gets you out of bed in the morning
it means that birds can fly, tigers can roar, wind can blow
it makes the sun, the moon and stars shine
it makes plants grow - food (= stored plant energy) for animals
it makes cars move, factories produce things, light bulbs glow, planes fly and your computer work. I'll bet you can think of many more!
Without energy, there would be nothing: no life, no movement, no light, no heat, no you, no me… nothing.
But there is a problem with energy. Some people have got used to using far too much of it. This means that there's not enough for everyone. And using some kinds of energy causes terrible pollution and makes the Earth's climate get hotter. Confused? No worries. Welcome to my new Energy Guide in which I take you on a journey through energy and, I hope, help you understand it.
Finding your way around my Energy Guide
What is energy? Energy is the ability to do work. It's what you get when you burn fuel (= stored energy) to move something like a car or kick a ball (= do work). That fuel can be stuff like coal or gas or the hydrogen which powers the sun. What you get is heat and light energy. You can feel the heat from a fire or from the sun on your skin. And sunlight makes our daytime.
Energy can be changed from one form to another but it can't be created or destroyed.
Where do we animals get energy from? Almost all energy comes from the sun which warms our planet and makes plants grow. Plants are smart because they can use the sun’s energy not only to make them grow, but also to make energy stores.
Most plants make seeds, some of which grow into new plants. And animals like you humans eat them - you know, wheat seeds make into bread; maize into popcorn or cornflakes and so on. This means you get your energy from eating plants, or by eating other animals like cows which have fed off plants.
I get my energy from
eating fish... ...which ate smaller fish which ate shrimpy things... ...which ate (you got it!) tiny plants called plankton. This is called a food chain. Our waste products eventually all go back to plants where they start the cycle again, fuelled by energy from the sun.
What are fuels? How do you get energy from them? Now this is where humans are different from all other life. You have learned how you can use fuels to make energy to power machines like cars, planes and computers. This way, you don’t have to work so much and you can stay warm without the fat, fur or feathers that other animals have. You get the fuel to make all this extra energy mostly by digging it out of the ground and burning it. This releases ancient energy stores - fossil fuels - made by billions of tiny plants and animals which lived millions of years ago. This stuff has been locked away underground ever since, covered up by younger rocks that got laid down on top.
I'm sure you know what these fuels are: These fossil fuels all come from underground; inside the Earth's crust. And that is where they should stay because burning them does a lot of damage to the air we all breathe, the oceans and living things on the land. You can burn any of these fuels, coal, oil or gas, to make electricity in power stations. How? But electricity is only one form of energy used by people. The biggest guzzlers of energy from burning fossil fuels are keeping homes and offices warm in winter and cool in summer transport: you know... cars, buses, some trains, ships and aircraft Fuels for heating can be any fossil fuel though people mostly use oil or gas because they're easier and less dirty. Machines for transport almost all use the liquid fossil fuel, oil. Why? But the oil has to be refined to make gasoline, diesel and kerosene. Different types of engine need different types of liquid fuel. coal oil gas
What’s the problem? What you don’t see so easily is the effects of burning all these fossil fuels. You can't see carbon dioxide and most of you don’t live near huge power station chimneys belching smoke, but no one can escape the noise and stink made by cars, trucks, boats, ships and aeroplanes. Did you know that there are over 500,000,000 cars and trucks in the world, all belching fumes? Then there’s the planes, ships and factories, all gushing smoke and poisonous gases into the air we all breathe.
What is pollution? Mostly it's smoke and gases which come from burning fuels to make energy. But it isn’t always obvious. Some of the polluting gases stink - yuk! That's obvious! Some pollution is clouds of black soot particles. Some pollutants are deadly poisonous and can kill people. But the main pollution is that colourless heavy gas which just about everyone has heard of: carbon dioxide (often shortened to CO 2 ). This gas has no smell and people use it to put the fizz in fizzy drinks. It is also a 'greenhouse' gas... and that spells trouble for the planet's climate. Most CO 2 comes from people burning fossil fuels and destroying forests.
Greenhouse Earth The Earth is warmer than it should be so the seas and oceans take up more space because warmer water expands. The warming is also making icy places like the Arctic and my home, the Antarctic, melt away. Lots of my penguin friends are dying because of this and because of pollution. The melted ice drains into the oceans, making sea levels rise even more. You’ve probably heard about the ‘greenhouse effect’. If you walk into a greenhouse on a sunny day, it’s very warm inside because the Sun’s heat is trapped by the glass. Carbon dioxide gas pumped into the air by burning fuels has just the same effect: it traps the Sun’s heat energy near the surface of the Earth making the air and oceans warmer. This is what scientists call climate change or global warming.
Warming also means more unpleasant weather with more and bigger hurricanes, typhoons, tornadoes and cyclones. That means lots of people will get killed - or go hungry because their land is flooded, washed away or their crops spoiled. Other places will get hot and dry as people cut down more and more forests
I don’t want to see these things happening and I don’t suppose you do either. So what can we do? Don’t worry! There are many ways to slow climate change without having to go without energy. Nuclear power — Help at hand? Possibly. Nuclear power doesn't add much to global warming — but it does create other types of wastes which are particularly nasty because they are radioactive. Radioactivity gets made inside nuclear power plants as the fuel - uranium metal - splits into other elements which give off radiation. So far, no one has worked out a way to safely dispose of the waste this makes, so at present it's all stored - huge quantities of it. And if the power plant goes wrong, terrible disasters can happen .
Let's now look at the energy alternatives , called renewables, so you can decide for yourself which energy source is best.
Sun power (solar power) can make electricity by using things called photovoltaic cells (often just called PV - easier to say) which fit on the roofs or walls of your houses or apartment blocks. Some special cars can run on PV electricity and there’s even a race across Australia in which the cars run only on solar power Solar power can also directly heat houses in cold countries - when they’re properly designed to make best use of it. So far, not many are Sun power can heat water in solar panels (like radiators but instead of giving out heat, they grab it from the Sun). This is then stored in a big tank so you can have hot showers and so on. Solar collectors can pick up the sun's heat even on cloudy days
Wave power can also drive generators but this is still a very new idea. Just a few experimental machines are in use today. Tides - you know, when the sea goes up and down twice a day - can drive generators too. There's just one example of this in action at a place called La Rance in France. Other parts of the world with big tides could be useful too, but a big dam has to be built to trap the moving seawater
Biogas (methane) for cooking and heating can be made from human sewage and farm animals' waste. (Phew! Yuk! … but very useful.) It's made in special tanks called biodigesters. Landfills - that's where people's garbage gets dumped - also produce methane gas as the rubbish rots. Usually this is collected and used to make electricity
Biofuels : Because plants and trees soak up CO 2 like sponges, making the carbon into wood and putting back oxygen into the air, people can ‘grow’ fuel without adding CO 2 pollution to the air. It's called 'carbon neutral'. In Brazil, people pioneered growing sugar cane plants to make alcohol which they use to power almost half the country’s cars. In other countries, people plant special trees (like willow) which grow fast and you can cut them down without killing them - so they keep on re-growing. This is called coppicing.
Fuel cells make electricity directly from hydrogen, a very light gas. The cells don’t burn the hydrogen. Instead it reacts with oxygen (in the air) to make electricity. The only ‘waste’ is water. Soon cars will run with fuel cells powering electric motors so they are silent and make no pollution. They can also make power for houses so there’d be no need for big polluting power stations. One way people can make hydrogen is by using sunlight to split water into hydrogen and oxygen gases. Scientists are still searching for a good way to do this.
Geothermal energy is energy tapped from inside the Earth. It's the only renewable energy source which has nothing to do with the Sun. Deep down, it's very hot. Sometimes these hot rocks break through the surface to form volcanoes. By drilling holes down into areas where hot rocks are close to the surface, people can generate electricity and heat buildings. One type of geothermal energy uses geothermal heat pumps to make hot water for home heating. A heat pump is a sort of reversed refrigerator.
Fair shares Some people are very greedy and want more than their fair share of everything. So they grab it, leaving little or nothing for anyone else. Many people in rich countries use much more energy than is sensible or fair. Fossil fuels will run out completely quite soon but before they do, the damage to the Earth ’ s climate will have been done.
What you can do But wait a moment. That doesn’t mean you’ve all got to grow fur or feathers. You, your friends and families could do lots to make things better: Be more careful with energy and save as much as you can by not driving around, flying and having the heating or air conditioning turned up so high. People can also save a lot by making clever buildings which can make their own energy and don't waste the energy they do use. Insulation isn't very exciting but it's the quickest, cheapest and best way to save energy in homes, schools and offices. Most buildings don't have proper insulation but there are simple ways to add it which not only means warmer (or cooler if you live in a hot place) buildings. Because much less energy is needed, you save lots of money: energy in getting very expensive to buy
Use your own energy to do things - cycling, walking, running, cooking (not fast-food - junky stuff. Yuk!) If you’re cold, wear more clothes! Find out more about renewable energy and pester parents and friends to get involved in using these or in trying to get something going where you live. And since energy use and climate change are connected, take a look at my Twelve Really Important Things you can do to help stop global warming
What do you think about energy and how it should be used? Have you any good ideas about what we can do to make things better? If you do, please write to me. Bye! Love from