Units 7 and 8, energy

Energy Light and electricity

What is Energy?It is the ability to do work. It moves vehicles,

lights and heats our home and even makes our bodies grow.

Forms of Energy:Light SoundHeatElectricity

Renewable energy sourcesSolar energy (sun)Wind energyGeothermal energyBiomass (plants)Hydropower (water)

Non-renewable sourcesPetrolCoalOilNatural gasNuclear

Some types of energy:Solar Power Chemical energy

LightThis is an energy called electromagnetic

radiation.When light passes through a prism, it

separates into a spectrum of colours called a rainbow.

Light PropertiesReflection Refraction

Tools to control and detect lightTelescopeMicroscopeBinocularsCameras

Energy and electricityOil, gas and coal are PRIMARY sources of

energy. Electricity is a SECONDARY source of energy.

We transform other sources of energy to make electricity. Electricity is transformed in power plants.

MatterMatter is made of atoms. Atoms are made of

electrons, protons and neutrons.When electrons move along wires, electricity

is produced.

ConductorsMaterials that allow electricity to flow, like

metals, are called CONDUCTORS.

InsulatorsMaterials that don’t allow electricity to pass,

like rubber and plastic, are called INSULATORS.

Using energyEnergy cannot be created or destroyed, but it

can be transformed into other types of energy:

- Batteries into light energy. - Electrical energy on phone into sound

energy.

Uses of EnergyIndustry: heat for steam or hot water,

factories for cooking, drying etc.Transportation: gasoline, diesel, electricity,

gas, etc. for vehicles.Public and residential use: electricity and gas

for heating and lighting in offices, hospitals, schools and homes.

Clean energyNon-renewable sources of energy like coal,

oil and natural gas cause air pollution.Renewable energy like sunlight, wind or

water is good. It replaces itself and doesn’t cause pollution.