Electricity Facts



  • Electricity is the energy that makes everything from toasters to televisions work. It is also linked to magnetism. Together, as electromagnetism, they are one of the four fundamental forces holding the Universe together.
  • Electricity is made by tiny bits of atoms called electrons. Electrons have an electrical charge which is a force that either pulls bits of atoms together or pushes them apart.
  • Some particles (bit of atoms) have a negative electrical charge; others have a positive charge.
  • Particles with the same charge push each other away. Particles with the opposite charge pull together.
  • Electrons have a negative electrical charge.
  • There are the same number of positive and negative particles in most atoms so the charges usually balance out.
  • Electricity is created when electrons move, building up negative charge in one place, or carrying it along.
  • Static electricity is when the negative charge stays in one place. Current electricity is when the charge moves. 106 Electricity, magnetism and radiation
  • Electric charge is measured with an electroscope.
  • Materials that let electrons (and electrical charge) move through them easily, such as copper, are called conductors. Materials that stop electrons passing through, such as rubber, are called insulators.
  • Most electricity is generated in power stations by magnets that spin between coils of wire to induce an electric current (see electric circuits).
  • The magnets are turned by turbines, which are themselves either turned by steam heated by burning coal, oil or gas, or by nuclear fuel, or turned by wind or water.
  • The stronger the magnet, the faster it turns, the more coils there are, so the bigger the voltage created.
  • Simple dynamos generate a direct current (DC) that always flows in the same direction.
  • The generators in power stations are alternators that give an alternating current (AC) which continually swaps direction. In an alternator, as the magnets spin they pass the wires going up on one side and down on the other.
  • The system of power transmission that takes electricity into homes was developed by Croatian-born US engineer Nikola Tesla at Niagara, USA in the 1880s.
  • Electricity from power stations is distributed around a country in a network of cables known as the grid.
  • Power station generators push out 25,000 volts or more. This voltage is too much to use in people’s homes, but not enough to transmit over long distances.
  • To transmit electricity over long distances, the voltage is boosted to 400,000 volts by step-up transformers. It is fed through high-voltage cables. Near its destination the electricity’s voltage is reduced by step-down transformers at substations for distribution to homes, shops, offices and factories.
  • An electric charge that does not move is called static electricity (see electricity). A charge may flow in a current providing there is an unbroken loop, or circuit.
  • A current only flows through a good conductor such as copper, namely a material that transmits charge well.
  • A current only flows if there is a driving force to push the charge. This force is called an electromotive force (emf).
  • The emf is created by a battery or a generator.
  • Currents were once thought to flow like water. In fact they move like a row of marbles knocking into each other.
  • In a good conductor there are lots of free electrons that are unattached to atoms. These are the ‘marbles.
  • A current only flows if there are more electrons at one point in the circuit. This difference, called the potential difference, is measured in volts.
  • The rate at which current flows is measured in amps. It depends on the voltage and the resistance (how much the circuit obstructs the flow of current). Resistance is measured in ohms.
  • A metal strip, moved by the torch’s switch, connects the current from the batteries to the light bulb. 110 Spring Batteries Switch Metal strip Light bulb
  • Batteries give out Direct Current (DC), a current that flows in one direction. Power stations send out Alternating Current (AC), which swaps direction 50-60 times per second.
  • Most electricity is generated in power stations by magnets that spin between coils of wire to induce an electric current (see electric circuits).
  • The magnets are turned by turbines, which are themselves either turned by steam heated by burning coal, oil or gas, or by nuclear fuel, or turned by wind or water.
  • The stronger the magnet, the faster it turns, the more coils there are, so the bigger the voltage created.
  • Simple dynamos generate a direct current (DC) that always flows in the same direction.
  • The generators in power stations are alternators that give an alternating current (AC) which continually swaps direction. In an alternator, as the magnets spin they pass the wires going up on one side and down on the other.
  • The system of power transmission that takes electricity into homes was developed by Croatian-born US engineer Nikola Tesla at Niagara, USA in the 1880s.
  • Electricity from power stations is distributed around a country in a network of cables known as the grid.
  • Power station generators push out 25,000 volts or more. This voltage is too much to use in people’s homes, but not enough to transmit over long distances.
  • To transmit electricity over long distances, the voltage is boosted to 400,000 volts by step-up transformers. It is fed through high-voltage cables. Near its destination the electricity’s voltage is reduced by step-down transformers at substations for distribution to homes, shops, offices and factories.