Power

First published in Supernova, the mag for curious kids volume 1, issue 1 in 2011. Reproduced with kind permission from BK Publishing.  Supernova: The mag for curious kids

Words by Dina Steyn

‘Power’ or, as it is sometimes called, ‘energy’ is an important part of modern life.  We use electricity to power everything from computers to lights. However, electricity is not the only kind of power that we use every day. Transportation such as buses, ships and aeroplanes also need sources of power to keep them moving. Let’s look at some of the things that can be used to generate (make) power.

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Many people use the terms “sustainable energy” and “renewable energy”, but what do they mean? Sustainable energy can be used for a long time without using up natural resources (like fossil fuels or water) or damaging the environment. Renewable energy can be used forever since it uses natural resources like the tides, sunlight and wind to generate power.

Fossil fuels

The word ‘fossil’ comes from the Latin word fossilis, which means ‘dug up’. Fossil fuels are coal, oil (petroleum) and natural gas and have to be mined or dug up. Fossil fuels are the most common source of power because we have been using them the longest for modern technology. We have been using fossil fuels, specifically coal, for almost 200 years. Coal is burned to generate electricity and oil is used to power our cars.

 

Text box: Are dinosaur bones and fossil fuels the same?

They are not exactly the same, but they are created in the same way. A fossil is usually the stone remains of something that lived millions of years ago. Both fossil fuels and fossils (like dinosaur bones) are dug up from the ground.  The earth creates them by slowly compressing (squeezing together) plant and animal remains for hundreds of millions of years.

 

There are two main reasons why people want to move away from fossil fuels. The one is that we are running out of fossil fuel. The number of people in the world and the need for electricity keep becoming more, but there is only so much fossil fuel. The other reason is that burning coal or using other fossil fuels pollutes the air.

Geothermal power

The word ‘geothermal’ comes from the Greek words geo (earth) and therme (heat). In other words, geothermal power comes from the heat within the earth. This heat is renewable and does not create pollution, but drilling deep into the earth can and does cause earthquakes.

Hydroelectric power

The word ‘hydro’ comes from the Greek word for water. The source of hydroelectric or water power is moving water like waterfalls, ocean tides or rivers. All kinds of power need machines to capture (trap) and store the power so it can be used later. Although the rivers and the oceans will not be used up, the machines smash and crush everything that come through them like fish and plants. This is one of the reasons that we don’t really use water power. The other is that fossil fuels give us more power than hydroelectric power.

Nuclear power

Think of something as small as a germ. Now try to imagine something smaller than that. An ‘atom’ is the smallest part of anything and is even smaller than a germ. Nuclear power depends on splitting (dividing) something that small into two. Since nuclear power works using atoms it does not use as many resources as burning fossil fuels. Nuclear power does not pollute the air.

One of the benefits of nuclear power is that once the reaction starts the process will release energy for a long time. This is also a problem since it is very difficult to stop a reaction when something goes wrong. Nuclear power produces radioactive waste. If the waste is not gotten rid of properly it sends out invisible waves that can poison people and the environment for thousands of years.

Solar power

Solar power is power that comes from the sun. You already use solar power without thinking about it when you hang washing in the sun to dry. Solar power can also be used to generate electricity. To use solar power, we need to capture the sun’s energy using solar panels. The first solar panels were huge and did not store much energy. This means that you needed a lot of space and many panels to create power.  The new solar panels store energy better and they take up less space – you can power a geyser with a 1 m² solar panel.

Wind power

Some farms still use wind pumps to bring up borehole water. Wind power can also be used to generate electricity. Wind turbines take up a lot of space and need to be somewhere where the wind blows constantly, for example, close to the sea.

New technology: plasma gasification

In science fiction we often hear about ‘plasma’ engines in space ships. The idea behind a plasma engine is that it uses any waste or rubbish and converts (changes) it to energy. We don’t have the technology to do that yet, but we are slowly getting there. Plasma is a specific type of gas that does not exist naturally on earth. Gasification is a process that turns things into gas.  The plasma gasification process uses plasma torches that burn warmer than the sun to turn waste into gas. The gas is used to generate power. The process’s own waste can be used as building materials. The process can even create clean water. It is also the only proven way to get rid of nuclear, hazardous and medical waste without affecting the environment. At present there are only three plants in Japan and the USA plans to build one.

Activity: Fun with static electricity

You will need one balloon.

Static electricity is caused by friction (two things rubbing together).  You’ve probably heard it yourself in winter when you take off a jersey and hear crackling noises.  This usually happens when the air is dry and it hasn’t rained for a while. Another way of seeing the effects of static electricity is taking a blown up balloon and rubbing it against your hair. The longer you rub the balloon against your hair, the higher the chance is that the balloon will stick to your hair!

More about Supernova, the mag for curious kids

Supernova, the mag for curious kids is an educational magazine, targeted at children between the ages of 9 and 14. This bi-monthly publication aims to make children aware of issues which affect them, their community and the environment, by giving them tools and inspiration to become active and responsible world citizens.

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