# Glossary

Alternating Current (AC) = an electric current that regularly reverses its direction
Amp = abbreviation of ampere, A
Ampere = 1 coulomb of charge per second = 6.24×1018 electrons per second, A.
Andesite = A light coloured volcanic rock made up of many tiny crystals
Bar = unit used to measure pressure, 1bar is 1 atmosphere is 1 000 hp
Borefield = An area with geothermal wells or bores
Centrifugal force = An imaginary force that makes a spinning object feel as though it wants to fly outwards
Circuit breaker = safety device that cuts the supply of electricity
Condenser = device for converting steam to water
Conduction = transfer of electrical energy from one atom to another.
Conduction = transfer of heat energy through a material, from one molecule to another
Conductor = something that will allow electricity to flow through it
Current = Flow of electrons through a material. Shown as I (intensity) in equations. Measured in Amperes (Amps)

Direct Current (DC) = an electric current that flows in one direction only.
Dry steam = Steam that contains no water droplets
Electricity = A form of energy and a flow of electrons from one atom to another
Electro-magnetism = Magnetism produced by an electric current.
Electromagnets = Magnets produced by electricity
Electrons = Negative charge in an atom, that orbits the nucleus.
Energy = the ability to do work and measured in Joules
Faraday = Michael Faraday, one of the greatest electrical experimenters in Science
Faraday’s law = A wire in a changing magnetic field will have a current induced in it.
Flashed Steam = steam made by lowering the pressure
Flux = the flow of energy, usually measured in Watts per square meter
Frequency = How often something happens each second e.g. 50 Hz

Generator = A machine that converts kinetic energy into electrical energy.
Governor = A control that maintains a steady speed of a machine
GWH = Abbreviation for Giga Watt Hour. Equal to 1 000 000 000 Watts per hour.
Heat = A form of energy caused by the movement/vibration of molecules
Hertz, Hz = Unit used to measure the frequency. 1Hz is one cycle per second.
Hydro power = Electricity generated using moving water
Hydro-electric = Electricity generated using moving water
Induction = Generating electricity in a wire, by a changing magnetic field
Joule = One watt-second = the energy released in one second by a current of 1 A
kV = kilo Volt (1,000 Volts)
Lenz = Heinrich Lenz, Estonian scientist who discovered Lenz’s Law
Lenz’s Law = an induced current will try to minimise the effect that caused it.

Magma = Molten rock that makes up the mantle of the earth
Magnetic field = the pattern of magnetism in the space around a magnet
Magnetic flux = the flow of energy, usually measured in Weber per square meter
Magnetic poles = the ends of a magnet where the magnetic force is greatest
Megawatt (MW) = 1 million Watts
National Grid = network of wires used to distribute electricity throughout NZ
Phase = Used to describe timing eg In phase maens the timing is the same.
Physics = The science of light, heat, radiation, electricity, magnetism, atomic structure
Poles = The ends of a magnet where the magnetic force is greatest
Power = A unit of power; power being the rate at which energy is used to do work = rate at which work is done, 1 W =1 J per second
Pressure = force in Newton’s on an area
Resistance = how hard it is for electricity to flow through something. Unit is Ohms.
Resistivity = How hard it is for electricity to flow through something
Rhyolite = A very light coloured volcanic rock with tiny crystals, that is gas-filled and explodes dangerously
Rpm = Abbreviation for revolutions per minute
Rotor = The part of a generator or turbine that spins

Sine wave = A perfectly smooth and uniform wave
Stator = part of a generator, made of electrical windings that do not move
Steam = water in its gaseous state
Steam turbine = A common type of turbine which is turned by expanding steam
Temperature = How heat is measured
Thermal plants = Power Stations using heat to generate electricity
Transformer = Electrical device for changing AC voltage and current
Three-phase = The most common way of generating and distributing AC electricity
Turbine = Machine that is made to spin by moving water or gases
Volt = international unit for measuring voltage, V
Voltage = amount of energy per unit charge. Measure in Volts
Watt = The unit of power = to 1 joule per second, W
Water vapour = Water as tiny invisible droplets which may form clouds and mist
Windings = repeated coils or turns of wire.