Heat at Home
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Central heating systems
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Heat travels through the air in invisible waves. If you were to stand close to a fire, you would feel heat coming from it. This is an example of radiation. The sun also warms the Earth through radiation. In a microwave oven, there is a transmitter that sends out waves of radiation to cook food. A toaster is another example of radiation in the kitchen. There are metal wires inside a toaster that radiate heat to toast the bread. If the bread were to touch these wires, that would be an example of conduction.
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Most houses have a central heating system to heat the rooms. A central heating system begins with a boiler or a heat pump. The boiler can be powered by burners that run on oil or natural gas, or by burning firewood, coal or peat in a stove. This generates energy to heat water inside the boiler. The hot water is then circulated in pipes throughout the house, reaching the radiators. Radiators are made of metal, which is a good thermal conductor. Radiators warm the air in the house by convection. Heat pumps capture heat from the air outside or underground, and use it to heat water for the central heating system. Some houses have underfloor heating. This uses hot water from the central heating system or electricity to heat the floor. Underfloor heating also warms the air in a house by convection.
Non-renewable and renewable resources
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Oil, natural gas, peat and coal are all fossil fuels. They are often burnt to power central heating systems in homes. They are non-renewable resources, which means that they will eventually run out. Burning fossil fuels can create smog or air pollution, as gas such as carbon dioxide is released into the air. This is linked to climate change.
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Renewable energy is generated using resources that will not run out. Renewable energy is becoming more popular, as people become more aware of the importance of protecting the environment. Renewable resources include wind power and solar power. Wind power uses wind turbines to generate electricity. Solar energy uses solar panels to convert sunlight into electricity.
Wind turbines
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