Physics P1a

Key Words

Fossil fuels

Fuels that are formed in the Earth over

millions of years from the remains of dead

animals and plants, for example coal, oil and

natural gas

Conduction

The transfer of thermal energy (heat) from the hotter parts of a substance to the colder parts of the

substance without the substance itself

moving.

Convection

•The transfer of thermal energy (heat) by the movement of a liquid or gas

Radiation

The transfer of thermal energy by infra-red waves

Chemical energy

The energy stored in fuel (including

food). This energy is released when chemical reactions

take place.

Kinetic energy

The energy of a moving object

Gravitational potential energy

The energy of an object due to its

position

Elastic energy

The energy stored in a springy object when we stretch or

squash it

Electrical energy

The energy transferred by an electric current

Thermal energy

The energy due to the temperature of

an object

Joules (J)

The unit of energy

Watt (W)

The unit used to measure power. 1 watt is 1 joule of energy transferred

each second

Kilowatt (kW)

is equal to 1000 watts

Kilowatt-hour (kWh)

the energy supplied to a 1kW device in

1 hour

Transformer

used to increase (step up) or reduce

(step down) the voltage

Solar cells

transfers energy from the Sun's

radiation directly into electricity

Solar panel

these absorb energy from the suns radiation and

transfer it as thermal energy

(heat)

Geothermal energy

thermal energy (heat) from inside the Earth. It is

produced from the natural decay of

radioactive material including uranium

Non-renewable energy

energy that gets used up and will

eventually run out

Turbine

this is made to turn by moving

water, steam or wind. It transfers kinetic (moving) energy from the

moving substance as its own kinetic

energy

Greenhouse effect

the Earth being kept warm by gases such as carbon dioxide in the atmosphere. Burning fossil fuels produces more carbon dioxide and so increases the greenhouse effect

Global warming

the earth's temperature rising due to the effect

of increased greenhouse gases

Efficiency

the fraction (or percentage) of the energy supplied to a device that is

usefully transferred

Nuclear fuels

radioactive substances such as

uranium and plutonium that are used for nuclear

fission in a nuclear power station

Acid rain

rain that is more acidic than usual

because of dissolved sulphur

dioxide or nitrogen oxides

Tidal barrage

a dam built across a river estuary so that electricity can be generated from

the tides.

Hydro-electricity

electricity generated using the

gravitational potential energy of

water stored behind a dam

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