Glossary

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A

Acid rain	airborne pollutants such as sulphur dioxide dissolve in atmospheric water vapour to form an acid.
Agriculture	the process of growing crops by cultivating large areas of soil.
Alternating current	an electrical current that reverses direction at regular intervals.
Anaerobic	in the absence of oxygen.
Atmosphere	a unit of air pressure. 1 atmosphere = 101 kilopascals (kPa) or 760 mm Hg.

B

Bagasse	waste product remaining after refining sugar cane.
Biogas	methane and carbon dioxide.
Biomass	organic material.

C

Carbon	the element that is one of the building blocks of all life.
Carbon cycle	the process by which carbon is taken up by plants and animals and returned to the environment in a continuous cycle.
Carbon dioxide	a gas that is the waste product of cell respiration and the combustion of fossil fuels.
Change of state	the process of a substance changing from a solid to liquid to gas or vice versa.
Chlorophyll	the green pigment found in plants responsible for photosynthesis.
Coal	the fossilised remains of plant material.
Cogeneration	harnessing heat that would otherwise be wasted in the fuel combustion process, producing two useful outputs: heat and power.
Comparative advantage	the advantage a nation has by being able to produce products or services more efficiently and at lower cost than a competitor nation.
Conservation law of energy	the total energy of a system always remains constant.

D

Decomposition	the break down of organic material into its basic elements.
Deforestation	the clearing of forests.
Doping	the process of making p-type or n-type material.

E

Electric current	the flow of electric charge in an electrical conductor.
Electrons	a negatively charged sub-atomic particle, which are the charge carriers in a metal conductor.
Energy crops	crops that are converted to an energy resource.
Ethanol	an alcohol that is the product of the fermentation of sugars.

F

Fermentation	a natural process where bacteria changes sugar to alcohol.
Fossil fuels	oil, gas and coal.
Frequency	as applied to electric current refers to how often an alternating current changes direction in a given period.

G

Gas	the state in which a substance exists when the forces of attraction between its particles are weakest.
Generator	a mechanical device that converts mechanical energy to electrical energy.
Gravitational potential energy	the stored energy of an object held above the earth's surface or the work done to lift it to that height.
Greenhouse effect	the process by which heat is trapped by the earth's atmosphere.
Greenhouse gases	the gases responsible for the greenhouse effect i.e. water vapour, carbon dioxide, methane, nitrous oxides and CFC's.

H

Head of water	the height of water above the turbines of a hydroelectric plant.
Heat Energy	the total kinetic energy of all the particles of a substance.
Heat of fusion	the energy required to change a solid to a liquid or vice versa.
Heat of vaporisation	the energy required to change a liquid to a gas or vice versa.
Hertz	the unit of frequency (per second).
Hydroelectric power	energy derived from the kinetic energy of moving water.

I

Incident light	light that strikes a metal surface in the photoelectric effect.
Incident photon	a photon that strikes a metal surface in the photoelectric effect.
Intensity of light	the number of photons being emitted from a light source.

J

Joule

the unit for energy. Sometimes seen as kilojoules (kJ) or megajoules (MJ) when large amounts of energy are involved.

K

Kilo	one thousand (1 000)
Kinetic Energy	the energy of a moving object (or mass).
Kinetic Theory	the theory that describes the state of matter in terms of the energy of its particles.

L

Latent heat

the energy required for a substance to change state.

M

Mega	one million (1 000 000)
Methane (CH4)	a gas that is the waste product of anaerobic digestion.
Mtoe (Million tonnes of oil equivalent)	the amount of oil required to release the same amount of energy as another energy source (for e.g. coal).

N

N-type material	a semi-conductor material that emits electrons.
Nitrogen dioxide (NO2)	a greenhouse gas released from the combustion of fossil fuels.

O

Organic

any living material.

P

Parabolic dish	a dish in the shape of a parabola.
Particulate matter	small particles of matter.
Photon	a discrete bundle of energy carried by light.
Photoelectric effect	this occurs when a photon strikes a metal surface causing an electron to be ejected.
Photoelectron	an electron that has gained kinetic energy from a photon.
Photosynthesis	a process by which green plants manufacture their own food from sunlight.
Photovoltaic cell	a semi-conductor material that converts sunlight directly to electricity.
Physical state	the state in which a substance exists at a certain temperature and pressure i.e. solid, liquid or gas.
Power	the rate of doing work or the rate at which energy is produced or used.
P-type material	semi-conductor material that accepts electrons.

Q

There are no terms beginning with Q.

R

Receiver	the part of a solar collector where the sun's light is focussed.
Renewable energy source	a source of energy that is not expected to deplete through constant use or can be replaced or grown within a relatively short period of time.
Respiration	the process of burning sugars to produce energy.

S

Solar cells	devices that convert sunlight directly to electricity.
Solar collector	a device that concentrates the sun's light to a point or absorbs the sun's energy.
Solar energy	energy from the sun.
Solid	the state in which matter exists where all its particles are packed tightly together.
Starch	the food produced by photosynthesis in plants.
Sulphur dioxide (SO2)	a greenhouse gas emission resulting from the combustion of fossil fuels.
Sustainable energy production	energy production that will not deplete energy resources.

T

Temperature	the average kinetic energy of the particles of a substance.
Threshold frequency	the lowest frequency of light required to eject a photoelectron.
Tidal power	energy derived from the movement of tides.
Transformer	a device that can change an input voltage to a higher or lower output voltage.
Turbine	a set of blades or rotors that spin when driven by gas, water or wind.

U

There are no terms beginning with U.

V

Voltage

electrical pressure or the work required to move a positive test between two points within an electric field.

W

Water vapour	gaseous water.
Watts	the unit of power. If large amounts of power are involved then megawatts (MW) are used.
Wind energy	energy derived from the kinetic energy of the wind.
Wind generator	a device that converts the kinetic energy of the wind to electrical energy.
Wind turbine	the same as a wind generator.
Work	is the change in kinetic or potential energy of a particle or work is done by a force F acting on an object during a displacement, s.
Work function	the energy that binds an electron to a metal. It is the minimum energy required by a photon to eject that electron.

X Y Z

There are no terms beginning with these letters.

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