1. Energy and Electricity
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Energy and Electricity
W Richards
The Weald School

2. Gravitational potential
The 9 types of energy
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Type
3 example sources
Type
3 example sources
Heat
Kinetic (movement)
Nuclear
Sound
Light
Chemical
Electrical
Gravitational potential
Elastic potential

3. Electricity Light + heat
Energy changes
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To describe an energy change for a light bulb we need to do 3 steps:
1) Write down the starting energy:
3) Write down what energy types are given out:
2) Draw an arrow
Electricity Light + heat
What are the energy changes for the following…?
An electric fire
A rock about to drop
An arrow about to be fired

4. Words – electrical (x2), light, chemical
Electrical Energy
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Consider a simple circuit:
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.
Words – electrical (x2), light, chemical

5. Electrical Energy
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Hi. I’m Ernie Electron and I’m going to show you how I get energy around a circuit.
Energy

6. Electrical Energy
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Hi. I’m Ernie Electron and I’m going to show you how I get energy around a circuit.
Energy

7. Electrical Energy
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Hi. I’m Ernie Electron and I’m going to show you how I get energy around a circuit.
Energy

8. Fuels
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A “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 Power

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Tidal Power

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Wave Power

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Hydroelectric Power

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Geothermal Energy

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Solar Power

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Power stations

16. What does each part do?
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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

17. Energy Transfer diagrams
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Consider 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:
“Input” energy
“Output” energy
20 J/s light energy
100 J/s electrical energy
80 J/s heat energy (given to the surroundings)

18. Example questions Consider a computer: Consider a kettle:
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Consider a computer:
150 J/s electrical energy
10 J/s wasted sound
20 J/s wasted heat
Useful light and sound
How much energy is converted into useful energy?
What is the computer’s efficiency?
Consider a kettle:
Work out each energy value.
What is the kettle’s efficiency?
Sound energy
Wasted heat
Heat to water
2000 J/s electrical energy