ELECTRICITY AND MAGNETISM UNIT 5

Transporting electricity The energy for generating electricity comes from different sources. The generator transforms energy (wind, water…) into electricity. The transformer changes the voltage of the electricity so can travel long distances. The cable transports an electric current from the generator to the transformer. The pylon holds electricity cables off the ground. Smaller transformers reduce the voltage in the town and make the electricity safer for us to use. The plug and socket connect a machine to the electricity supply.

STATIC ELECTRICITY Static electricity can make when we rub two non-metal objects together. All objects have electrical charges. They can be positive or negative. If an object contains more positive charges than negative charges, it has a positive charge. If an object contains more negative charges than positive charges, it has a negative charge. Objects with opposite electrical charges attract each other. Objects with the same electrical charge repel each other.

Current electricity Electric current is the movement of electrical charges. Electrical insulator doesn’t allow electric current to flow easily through them: wood rubber, plastic and glass. Electrical conductor can flow easily electric current: copper, iron, aluminium (metals) and water. An electric current can only pass through a circuit that is closed. ELECTRIC CIRCUIT is usually made up of: Generator: supplies the electricity. Conductor: lets the electricity flow through the circuit. (metal wires – copper wires) Electrical component: transforms electricity into another form of energy. (light bulb – light energy) Switch: opens and closes the electric circuit.

MAGNETISM Magnetism is the ability to attract metals, iron and mixtures of iron-. A magnet is an object which can attract certain metals. It can be : natural (magnetite) or man-made. It can be different shapes and sizes. It has two poles: north and south pole. The poles are the parts of the magnet which attract metal objects. When two magnets touch at the poles: If we put the same poles together, the magnets repel each other. If we put opposite poles together, the magnets attract each other. A magnetic field is the area of magnetic force. We can’t see it. But you can see the effects of it. Electromagnet is temporary magnets. An electromagnet is only a magnet when an electrical current flows through the coil around it.

SOURCES OF ENERGY Energy sources provide us with the energy that we need to make electricity Renewable Non-renewable Uranium sunlight, wind, water Fossil fuels Biomass Geothermal