Physics GCSE: Energy Transfers
Non-Renewable energy sources
Generating electricity in power stations
All power stations use a similar process to produce electricity. - Fuel is used to produce heat energy.
- The heat energy heats water and turns it into steam.
- The steam is pushed at high pressure along pipes to the turbines.
- The steam makes the turbines spin, turning a generator which then produces electricity.
The electricity is then supplied to houses, factories and schools via the national grid. Drag the correct form of energy directly onto the actual source of the energy and mark you answer:
Fossil fuels
The fossil fuels are oil, gas and coal. They are non-renewable energy sources, which means when the existing supplies run out,they can't be replaced! We are very reliant on fossil fuels in the modern world.
Do you remember all the aggro during the fuel crisis of September 2000 when there was a sudden shortage of petrol and diesel (both made from oil)?
These fuels have many uses, but the main ones are for heating, transport and generating electricity. The USA uses more fuel per person than any other country and much of the developed world uses plenty. As developing countries become more industrial, they use more and more energy.
Fossil fuels are formed under the ground. Dead matter is squashed under extremely high pressure over millions of years. This is why we can't remake it when it runs out.
Environmental impact of fossil fuels
When you burn any fossil fuel, gases escape into the air. The main two gases released are carbon dioxide and sulphur dioxide.
(Note: One reason why petrol tax is high in the UK is because the government was trying to discourage car use so that less pollution is released into the air.)
Carbon dioxide is the most common of several gases that contribute to the greenhouse effect. I think the effect is best experienced under a duvet! The heat that exists underneath can't easily get out, so you get hotter and hotter. For the Earth, the result is global warming. Sadly, it means more heat energy in the atmosphere, so the weather is more extreme (not just hotter). Worse still, is that the ice-caps melt raising the sea levels. Literally millions would be affected in countries like Bangladesh, even parts of England could go under the water.
Sulphur dioxide causes acid rain. The gas dissolves in rainwater to form an acid. The acid rain harms plants, animals and stonework. It is an international problem because acid rain clouds created in one country can be blown over to another country.
Nuclear power
When your parents went to school, nuclear power stations were the great hope to solve all the world's energy problems. 1 kg of Uranium can produce the same amount of energy as 10,000 kg of coal. Since then, the negative side to nuclear power has changed many people's view. Accidents at power stations like Chernobyl showed us that although nuclear power has many advantages over the fossil fuels, it is also highly dangerous.
Uranium is the fuel used in many nuclear power stations. Uranium is not burnt like coal or gas. Instead nuclear fission takes place. Atoms of uranium are split up which releases large amounts of energy. Left uncontrolled this could cause an explosion as in nuclear weapons, but when controlled the energy can be used to heat water to produce steam, just like in other power stations.
Unfortunately, nuclear fission produces harmful radiation. Radioactive substances are produced that release alpha, beta and gamma radiation into the surroundings. This can be harmful to plant and animal life.
Accidents are rare, but can be serious. After the Chernobyl accident in the Ukraine, radioactive particles were carried in clouds across Europe contaminating land hundreds of miles away from the accident. 15 years later, there is still an area around the power station that people are not allowed into.
The waste from the reactors is also radioactive. It can be stored safely, but it stays radioactive for years. Unfortunately this waste has to be stored somewhere but nobody wants the nuclear waste buried near their town!
So where are we going to keep putting it?
