Alternating current: Also known as AC power, alternating current is electricity that reverses direction within a circuit. The electricity we use in our homes does this 120 times per second.

Amp: The ampere, often shortened to amp, is the unit of electric current. It is named after André-Marie Ampère (1775–1836), the French mathematician and physicist, considered the father of electrodynamics.

Appliances: Devices used in the home, at work and at school, such as a heaters, fridges, toasters, computers.

Atmosphere: The layer of gases that surrounds the earth.

Atom: A basic unit of matter. An atom consists of a central nucleus surrounded by a cloud of negatively charged electrons. Everything in the world is made of different combinations of atoms.

Biomass: Biomass is biological material derived from living, or recently living organisms. As a renewable energy source, biomass can be burned to produce energy or used as a fuel.

Carbon dioxide: A colourless, odourless, non-poisonous gas that is a normal part of the air we breathe. Carbon dioxide is exhaled by humans and animals, and is absorbed by green growing things and by the sea.

Chemical energy: Energy that is released by a chemical reaction.

Chemical reaction: A process that changes one substance into another. For example, chemical reactions that take place during digestion change energy in food into substances that the body can use to do work.

Circuit: A circular path in which electricity travels.

Climate Change: Changes in temperature, rainfall, wind, heat and other aspects of the earth's climate that last for an extended period.

Compact fluorescent lights: Lights that use a lot less energy than regular light bulbs. Also known as CFLs.

Conductor: Something that allows electricity to flow through it easily. Water and most metals are good conductors. Conductors can allow electricity to flow through them because the electrons in their atoms move between atoms very easily.

Current: a movement or flow of electrically charged particles, usually measured in amperes.

Direct current: Electricity that flows in only one direction in a circuit. Batteries use direct current electricity, also known as DC power.

Distribution lines: Power lines that deliver electricity to homes and businesses. These lines can be overhead or underground.

Electrical Energy: A form of energy that arises from the flow of electrons.

Electricity: The flow of electrons.

Electricity Supplier: There are two types of electricity supplier in New Zealand: lines companies and retailers. The electricity lines companies own the poles and electricity wire; the electricity retailers sell the power provided by the lines companies to customers and send them a power bill.

Electron: The particle that orbits the nucleus of an atom. The flow of electrons produces electricity.

Energy: The ability to work, move and play. People get energy from food. Your fridge and your TV get their energy from electricity.

Energy Efficiency: Using less energy while getting more from your appliances and equipment. You can do this by being energy-efficient or using energy-efficient technology.

Environment: All the natural and living things around us. The earth, air, weather, plants, and animals all make up our environment.

Fission: The splitting of an atom's nucleus. This releases a large amount of heat energy.

Fluorescent bulb: the gas in the bulb glows when charged by electricity.

Fossil fuels: Fuels formed in the ground from the remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas and coal are fossil fuels. Petrol and diesel fuel are also made from fossil fuels.

Fuel: A substance that can be burned to make energy.

Fuel cell: A device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. This is similar to that found in a battery.

Generator: A machine for converting mechanical energy into electricity.

Geothermal energy: Energy generated by converting hot water or steam from under the Earth's surface into electricity.

Glaciers: Large bodies of ice that move slowly down a slope or spread outwards on a land surface.

Greenhouse gases: Carbon dioxide, methane and ozone. These gases form layer around the earth that absorbs and radiates heat from the sun.

Hydroelectricity/Hydropower: Electricity generated when falling water makes a turbine in a power station spin.

Hydrogen: A colorless, highly flammable gaseous element, the lightest of all gases and the most abundant element in the universe.

Insulator: Something that electricity cannot flow through easily, because the electrons in their atoms do not move easily from atom to atom. Glass and some rubber are good insulators.

Incandescent bulb: the heated filament inside the bulb glows when charged by electricity.

Kilowatt: 1,000 watts of electricity.

Kilowatt–hour: One kilowatt of electricity produced or used in one hour.

Landfills: Places where rubbish is buried.

Mechanical energy: The energy of motion that can move objects from place to place.

Megawatt: 1,000,000 watts of power or 1,000 kilowatts.

Methane: An odorless, colorless, flammable gas, the main ingredient of natural gas.

Natural gas: A mixture of hydrocarbon gases that occurs within petroleum deposits, which is formed naturally in the earth when organic material decomposes under pressure. Natural gas is used as a fuel. Natural gas is a fossil fuel and is often found with oil.

Neutron: A particle in an atom's nucleus that has a neutral electrical charge.

Nucleus: The positively charged centre an atom, composed of protons and neutrons and containing almost all of the mass of the atom. Orbiting around the nucleus are electrons.

Nonrenewable fossil fuels: Fuels that can be used up because they cannot be easily made or "renewed". Oil, natural gas and coal are nonrenewable fossil fuels.

Nuclear energy/nuclear power: Energy that is released from splitting atoms of radioactive materials (such as uranium) and then harnessed to generate electricity. New Zealand does not use nuclear energy.

Oil: A liquid fuel found deep in the earth. Petrol and some plastics are made from oil. Natural gas is often found in or near oil deposits.

Photovoltaic cell: A device that changes sunlight into electricity.

Polyethylene: A component found in oil that is used in the production of a number of products such as containers, kitchenware, tubing, and sheets or films for insulation. Supermarket bags are also made of polyethylene and so are gas pipes. Although the Polyethylene used in gas pipes is much thicker and very strong!

Power station: A place where electricity is generated.

Power line: A wire used to carry electricity. Power lines run overhead or are buried underground.

Processing plant: A facility that takes a crude substance (such as oil) and refines it/processes it into products such as gases (propane, natural gas) or clean drinking water.

Proton: A particle in an atom's nucleus that has a positive electrical charge.

Radiant energy: Any form of energy radiating from a source, such as heat from the sun or a fire.

Renewable: Means replaceable. If something is renewable it can be replaced or remade.

Renewable resources: Fuels that can be easily made or "renewed". We can never use up renewable fuels. Types of renewable fuels are solar, wind, and hydro.

Reservoirs: Natural or artificial ponds or lakes used for the storage of water. Often used by hydro power stations.

Solar cells: Solar cells collect sunlight and convert it into electricity.

Solar energy: Energy from the sun.

Solar panel: A device that coverts energy from the sun into electricity.

Static electricity: A form of electrical energy that results from an imbalance of positive and negative charges.

Substation: A substation is a place where transformers lower the voltage of electricity before it is sent through power lines to our homes.

RCD (Residual Current Device): RCDs are safety devices found on appliance cords and power points. If an RCD detects electricity leaving a circuit, it quickly shuts off the electricity to prevent serious shock.

Thermostat   : A device that controls the temperature of a heater or air conditioner.

Transfer of energy: When one energy source moves or changes another source.

Transformer: Transformers increase or decrease electricity's voltage and current.

Transmission: the high voltage transmission network (known as the national grid) that connects power stations with local electricity network companies (like Vector) across New Zealand. Transpower owns the national grid in New Zealand

Transmission lines: Power lines that carry high-voltage electricity long distances.

Turbine: Turbines are used to generate electricity. It has a shaft with blades at one end and electromagnets at the other. Moving fluid acts on the blades in a turbines so spin a shaft and magnets which are surrounded by coils of copper wire. The spinning magnets cause electrons in the wire to begin to move, creating electricity. Early turbine examples are windmills and waterwheels.

Utility: A company or organisation that provides a public service, such as supplying electricity, gas, water or sewerage.

Voltage, volts: A measure of the pressure under which electricity flows.

Watts: A unit of power equal to one joule per second

Wattage: the power rating, measured in watts, of an electrical appliance.

Weather-stripping: A type of material used to seal a door or window around the edges to keep the hot or cold air from coming in or out.

Wind energy: A renewable energy source that uses the force of the wind to spin turbines and generate electricity.