Science

• Electricity is generated in power stations from non-renewable sources, such as gas or coal. It is also generated from renewable sources, such as wind turbines and solar panels.

• Appliances like mobile phones use very little electricity whereas heating appliances use much more.

• You can use less electricity by switching off lights and not leaving appliances on standby.

In the UK, much of our electricity is supplied by generators in power stations. A generator is a magnet that is placed at the centre of a wire coil. Rotating the magnet produces an electric current.

In all power stations the generators are turned by turbines. The turbines are turned by high pressure steam, which is produced by heating water with the fuel. In fossil fuel power stations, water is heated by burning gas, oil or coal. In nuclear power stations, the water is heated by energy transferred from nuclear reactions. Fossil fuels and nuclear fuels are non-renewable.

Renewable energy sources include wind, moving water (hydroelectric), and sunlight. Wind turbines use wind to directly power a turbine. Hydroelectric power stations use moving water to power a turbine. They both rely on movement, rather than heat, to generate power. Solar cells, on the other hand, convert sunlight directly to electricity, requiring neither turbines nor generators.

• Solar energy is energy that comes from the Sun.

• Solar panels use sunlight to make electricity.

• Solar energy is renewable and therefore better for the environment.

Solar energy is energy in the form of light, produced by the Sun.

Light from the Sun comes as ultraviolet, visible and infra red rays. Visible light is the spectrum of colours we are used to seeing but ultraviolet and infrared cannot be seen.

Solar energy is a renewable source of energy. It is free and does not damage the environment.

Most electricity is made by burning fossil fuels, which release carbon dioxideand pollution.

Solar energy does not release anything into the air, so it is a clean source of energy and does not damage our planet.

When light hits a solar panel it reacts with silicon crystals in each solar panel to produce an electric current.

The electric current can then be fed into the National Grid.

The National Grid is the system of cables and wires that transfer electricity from power stations to houses and businesses across the country.

Space engineers include solar panels on satellites to produce the energy needed to run their electric circuits.

This is because it is not possible to provide further fuel to the satellites after they have launched, they need to capture the free energy from the Sun.

• Combustion is the scientific word for burning.

• In a combustion reaction a substance reacts with oxygen from the air and transfers energy to the surroundings as light and heat.

• The products of a combustion reaction are called oxides.