Energy Transfer Diagrams

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Energy Transfer Diagrams

• Starter Activity (back of jotters)
• What are the 10 types of energy?
• Draw an energy flow diagram for an ipod

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Energy Changes
What are the energy changes for a person on a
tricycle?
Kinetic Energy
Sound Energy
Heat Energy
Chemical potential energy in food
What is wasted and what is useful energy?
3
Battery powered television set
Electrical Energy
Light Energy
Sound Energy
Chemical potential energy in battery
Heat Energy
What is wasted and what is useful energy?
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Energy Diagram
We show how energy is transferred using Energy
Diagrams
300 J
Heat
Electricity
500 J
200 J
Light
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Energy Diagrams
Whats wrong with this Energy diagram?
300 J
Heat
Electricity
500 J
200 J
Light
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Accurate Energy Diagrams
Filament bulb
9J wasted heat energy out
10J electrical energy in
1J useful light energy out
The total energy in is equal to the total energy
out
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Draw an Energy diagram for the following on graph
paper.
1) A lawnmower. Input 100J electrical Output
70J useful kinetic 30J wasted heat
2) A wood fireplace Input 100J chemical
potential Output 40J useful light 40J
useful heat 20J wasted sound
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Which light bulb would you buy and why?
Filament bulb
9J wasted heat energy out
10J electrical energy in
1J useful light energy out
Energy efficient bulb
6 J wasted heat energy out
4J useful light energy out
10J electrical energy in
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Energy Efficiency

• An Energy Diagram can tell us how much useful
  and wasted energy we will get from a device like
  a bulb. The more useful energy we can get out of
  it, the better.
• This is called the energy efficiency

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Energy Labels

• Machines have labels which
• tell customers how efficient
• their appliance (washing machine/TV
• etc) is.
• Why would we want to know this?