Glossary:

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Dissipation – Becoming spread out wastefully

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Energy – Energy is needed to make things happen

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Fossil Fuel – Non-renewable energy resources formed over millions of years from the remains of ancient plants or animals

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Joule – The unit of energy, symbol J

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Non-renewable – An energy resource that cannot be replaces and will be used up, such as coal, oil or gas.

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Power – How quickly energy is transferred by something (unit Watts)

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Renewable – An energy resource that cannot be replaced and will run out.

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Conduction: Transfer of thermal energy by the vibration of particles.

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Convection: Transfer of thermal energy when particles in a heated fluid rise.

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Convection current: The movement of heated fluids where hot fluid moves upwards, and cold fluid moves downwards.

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Infrared radiation: Radiation given off by the Sun and other objects that brings about energy transfer

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Thermal conductor: Material that allows heat to move quickly through it.

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Energy Transfer

• Energy cannot be created or destroyed, it can only be transferred between stores. This is the law of conservation of energy. An energy store is a way of keeping track of energy.
• Radiation (like light), heating, forces and electricity are ways of transferring energy between stores.
• Energy is dissipated in any energy transfer process because of friction, air resistance, electrical resistance and the heating of surroundings by hot objects.
• You can calculate the useful energy or the waster energy from the energy input and energy output.

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Energy transfers

Heating and cooling

• The thermal energy of an object depends on its mass, temperature, and what it is made of. When a hot object is in contact with a colder one energy is transferred from the hot object to the colder one.
• Energy is transferred by conduction in solids and by convection in liquids and gases.
• Energy travels quickly through a thermal conductor, but more slowly through a thermal insulator. Some insulators work by trapping air, which is a poor thermal conductor.
• Energy is transferred by radiation, which does not need a medium to travel through. All objects emit radiation, Infrared radiation can be detected by your skin or a thermal imaging camera.�

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Fossil fuels

We get energy from many different types of energy resources, including fuels, food and stores of energy such as batteries or the wind. We can divide energy resources into two categories:

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-non-renewable energy resources cannot be replaced once they are all used up

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-renewable energy resources can be replaced, and will not run out

Fossil fuels are non-renewable energy resources.

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Fossil fuels

Crude oil, coal and gas are fossil fuels. They were formed over millions of years, from the remains of dead organisms:

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coal was formed from dead trees and other plant material

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crude oil and gas were formed from dead marine organisms

Energy transfers