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energy and electricity
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11/22/14
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.
11/22/14
Wind PowerWind Power
11/22/14
Tidal PowerTidal Power
11/22/14
Wave PowerWave Power
11/22/14
Hydroelectric PowerHydroelectric Power
11/22/14
Geothermal EnergyGeothermal Energy
11/22/14
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?