energy and electricity

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Energy and ElectricityEnergy and Electricity

W Richards

The Weald School

11/22/14The 9 types of energyThe 9 types of energyType 3 example sources

Heat

Kinetic (movement)Nuclear

SoundLight

Chemical

ElectricalGravitational potential

Elastic potential

Type 3 example sources

11/22/14Energy changesEnergy changesTo describe an energy change for a light bulb we need to do 3 steps:

Electricity Light + heat

1) Write down the starting energy:

3) Write down what energy types are given out:2) Draw an arrow

What are the energy changes for the following…?

1) An electric fire

2) A rock about to drop

3) An arrow about to be fired

11/22/14Electrical EnergyElectrical EnergyConsider a simple circuit:

Words – electrical (x2), light, chemical

The job of the battery is to convert ______ energy into _________ energy…

The job of the bulb is to convert the _________ energy it receives from the battery into ______ energy.

11/22/14Electrical EnergyElectrical Energy

Energy

Hi. I’m Ernie Electron and I’m going to show you how I get energy

around a circuit.

11/22/14Electrical EnergyElectrical Energy

Energy

Hi. I’m Ernie Electron and I’m going to show you how I get energy

around a circuit.

11/22/14Electrical EnergyElectrical EnergyHi. I’m Ernie Electron and I’m going to show you how I get energy

around a circuit.

Energy

11/22/14FuelsFuelsA “fuel” is something that can be burned to release heat and light energy. The main examples are:

Coal, oil and gas are called “fossil fuels”. In other words, they were made from fossils.

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Wind PowerWind Power

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Tidal PowerTidal Power

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Wave PowerWave Power

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Hydroelectric PowerHydroelectric Power

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Geothermal EnergyGeothermal Energy

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Solar PowerSolar Power

11/22/14Power stationsPower stations

11/22/14What does each part do?What does each part do?The boiler is where the fuel is burnt to boil water

The steam from the boiler is used to turn a turbine

The turbine is connected to the generator, which acts like a dynamo – it generates electricity out of movement

The steam is cooled down and turned back into water in the cooling tower

11/22/14Energy Transfer diagramsEnergy Transfer diagramsConsider a light bulb. Let’s say that the bulb runs on 100 watts (100 joules per second) and transfers 20 joules per second into light and the rest into heat. Draw this as a diagram:

100 J/s electrical

energy

“Input” energy “Output” energy

80 J/s heat energy (given to

the surroundings)

20 J/s light energy

11/22/14Example questionsExample questionsConsider a kettle:

1) Work out each energy value.

2) What is the kettle’s efficiency?

Sound energy

Wasted heat

Heat to water

2000 J/s electrical energy

Consider a computer:150 J/s electrical energy

10 J/s wasted sound

20 J/s wasted heat

Useful light and sound

1) How much energy is converted into useful energy?

2) What is the computer’s efficiency?