units 7 and 8, energy

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Energy Light and electricity

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Page 1: Units 7 and 8, energy

Energy Light and electricity

Page 2: Units 7 and 8, energy

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

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

Page 3: Units 7 and 8, energy

Forms of Energy:Light SoundHeatElectricity

Page 4: Units 7 and 8, energy

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

Page 5: Units 7 and 8, energy

Non-renewable sourcesPetrolCoalOilNatural gasNuclear

Page 6: Units 7 and 8, energy

Some types of energy:Solar Power Chemical energy

Page 7: Units 7 and 8, energy

LightThis is an energy called electromagnetic

radiation.When light passes through a prism, it

separates into a spectrum of colours called a rainbow.

Page 8: Units 7 and 8, energy

Light PropertiesReflection Refraction

Page 9: Units 7 and 8, energy

Tools to control and detect lightTelescopeMicroscopeBinocularsCameras

Page 10: Units 7 and 8, energy

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.

Page 11: Units 7 and 8, energy

MatterMatter is made of atoms. Atoms are made of

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

is produced.

Page 12: Units 7 and 8, energy

ConductorsMaterials that allow electricity to flow, like

metals, are called CONDUCTORS.

Page 13: Units 7 and 8, energy

InsulatorsMaterials that don’t allow electricity to pass,

like rubber and plastic, are called INSULATORS.

Page 14: Units 7 and 8, energy

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.

Page 15: Units 7 and 8, 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.

Page 16: Units 7 and 8, energy

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.