Electricity

Electricity is energy We use energy to heat and cool our homes. for lights and appliances. run cars, planes, boats and machines All living things need energy too. plants use the light from the sun to grow. animals and people eat the plants and use the energy that was stored. food is fuel for our bodies' energy needs, like muscle power. We also use our own bodies to make heat energy. when you have been running or working really hard, your body produces heat energy. when you wear clothing like a jacket in the winter, it holds in that heat energy and keeps you warm.

History of energy The very first energy source was the sun providing heat and light during the day. Fire was discovered by a lightning strike, producing another source of heat and light. Thousands of years later we discovered that the wind could be harnessed and we began to use sails on our boats for transportation. Later we began to use windmills to turn wheels for grinding grain During the 1800’s steam engines were beginning to be used to power pumps, machines and steam trains. Coal was used as fuel. Around 1816 manufactured ‘town gas’ made from coal, was first used for street lights in Baltimore, USA The first public power station was built in London in 1882 which supplied electricity to local premises. From about 1945 to the present, nuclear and solar energy along with water and wind have played a larger role in the production of energy Other alternative energy sources being used today are geothermal and biomass Thomas Edison invented more than 2,000 new products, including almost everything needed for us to use electricity in our homes: switches, fuses, sockets and meters.

How electricity is made Have you ever wondered where electricity comes from? You might be surprised to learn that it comes from magnets! In the early 1800s, Michael Faraday discovered "electromagnetic induction", which is the scientific way of saying that if he moved a magnet through a loop of wire, the wire would become electrified. Thomas Edison's electric generator (in the first power station) was a bigger version of Faraday's basic experiment; a big magnet rotating around a wire to produce an electric current. Today's power plants are bigger and controlled by computers, but the basic process is still the same as it was nearly 120 years ago. Electricity is the flow of moving electrons. When the electrons flow it is called an electrical current.

Making electricity from coal Coal heats water which turns to steam The steam spins a big fan called a turbine. The spinning turbine rotates a big magnet around a piece of wire & that motion creates a magnetic field that electrifies the wire. Electricity is created. The electric current flows from the generator to high-voltage transformers.

Electricity manufacture You can produce electricity in all kinds of different ways Some power plants burn natural gas instead of coal to make steam. A nuclear power plant splits apart uranium to release heat energy A wind farm uses the wind to spin the blades of the turbine. Turbines can be on land or off shore A hydro power plant uses running or falling water to spin the turbine. Solar power plants are now in operation Electricity from the sun

From Power Plant to TV ! Electricity is made in a power plant some distance from your home Plug in your TV and electrical energy flows into it through a cable The cable is much longer than you might think: it actually runs all the way from your TV— underground & through the air—to the power plant Electricity moves through the cables very fast. In just one second, electricity can travel around the world seven times. Electricity travels at the speed of light - more than 186,000 miles per second!

Safe transport of electricity Electricity flows from the power plant through wires to transmission substation which changes the voltage of the electricity to make it safe The electricity flows through aluminium and steel cable lines held up by huge towers & called the transmission lines The electricity enters the power substation and voltage is reduced again Distribution lines carry small amounts of electricity from the substations to houses and businesses

What next ? Complete the Student Worksheet Watch the PowerPoint on Electrocution of Birds of Prey