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Energy TransferSyllabusTitle PageLesson 01 Types of EnergyLesson 02 Energy EfficiencyLesson 03 Conduction and ConvectionLesson 04 Radiation and InsulationLesson 05 Insulating Homes


Energy


Energy Transfers 21/04/23Aim: To define energy To explain the purpose of a transducer and their

role in the conservation of energy To identify energy transfers

Starter: in rough Write down words / phrases about energy Compare with your neighbour Compare with your table Agree a definition of energy and one of you write it

down (can be more than one sentence)


EnergyDefinition:

Energy is required to do anything (work) (e.g. heat up). Energy is always conserved, it is never used up or

destroyed it is transferred into another form (e.g. chemical to heat and light).

A transducer changes energy from one form to another (e.g. a match).

Symbol: EUnit: J (joules)

Analogy: Energy is like money. To do anything costs money. Money is not used up but changes hands when you pay for

something.

Handout Demo Burning Ethanol


Types of energy There are two groups of energy and nine types you

need to learn In rough write down what types of energy you can

think of in 1 minute (think about the burning ethanol demo)


Types of Energy

Electrical energy

ACTIVE (KINETIC) ENERGY STORED (POTENTIAL) ENERGY


Types of Energy _________ _______ (KE) are all types of movement energy. _________ _______ (PE) are all types of stored energy.

Type KE or PE?

Example Sources

Kinetic (movement)

Heat (thermal) KE flame

Light

Gravitational

Chemical

Sound

Electrical

Elastic

Nuclear

Kids Hate Learning GCSE Energy Names


On your white board write down the type of energy

1. Energy in a toffee

2. Energy in a running girl

3. Energy causing a light bulb to light

4. Energy given off by a stationary boy

5. Energy in music

6. Energy in a spring shot

7. Energy in a diver


Energy TransfersWatch the demo (flour fire breathing)What energy transfers are occurring?


Example Energy Transfers?

electrical kinetic

kinetic electricalelectrical sound

light chemical


There can be more than one step

More Complicated Examples

gravitational potential

kinetic

electrical

Energy can be transferred into more than one type

electrical

light

heat sound


Energy Circus Around the lab are a selection of transducers. For each one identify

All the energy transfers (every stage) Underline useful transfers Bracket wasted transfers Write the name and transfers into your books

Example (try in your books in pencil)1. Catapult Girl

Chemical

kinetic

kinetic

(heat)

elastic gravitation

al(heat)

(sound)

Elastic


Identifying energy transfers


Energy Transfers recapAim: To define a energy To explain the purpose of a transducer and their

role in the conservation of energy To identify energy transfers

Plenary: on whiteboards Write down the two most important things you have

learnt this lesson.


Efficiency 21/04/23Aim: To create sankey diagrams To calculate efficiency

Starter: Watch the Movie (Roller Coaster) Identify the energy transfers How is energy wasted?


Wasted sound energyIf you can hear a device that is not designed to make noise then energy is wasted as sound.

Examples of devices that waste energy as sound include:


Wasted Heat EnergyIf a device gets warm and it is not designed to get warm then energy is wasted as heat.

Examples of devices that waste energy as heat include:


Which Type of Energy is Wasted?


Wasted Energy Energy is normally wasted as heat and sound Wasted energy dissipates (spreads out) into the

surroundings. This dissipated energy is too spread out to do useful

work and so cannot be re-used.


Sankey Diagram – A Candle


Sankey Diagram – A Candle

Energy in: Every second the candle transfers 100 joules of chemical energy

Energy out: 20 joules into light energy and 80 joules into heat energy

100 J electrical energy

“Input” energy “Output” energy

80 J heat energy

20 J light energy

So each block represents 10J

Only the width matters not the length


Sankey Diagram – Running Man


heat energy

sound energy

kinetic energy

2000 J electrical energy

Sankey Diagram - Running Man Energy in: Every second the man transfers 2000 J of chemical energy

Energy out: ? of useful kinetic, ? of useful sound, ? of wasted heat

So each block represents 200 J


Questions• Draw Sankey diagrams for the following on graph paper.• Highlight the useful energy.• Leave the right hand side of the graph paper empty.1. Light Bulb

input: Electrical 200Joutput: Light 30J, Heat ?J

2. Fireinput: Chemical 200Joutput: Heat 150J, Light ?J and Sound 20J

3. Drill input: Electrical 1000Joutput: Kinetic 300J, Sound 200J, Heat ?J

4. Computerinput: Electrical ?Joutput: Sound 50J, Light 100J, Heat 80J and Kinetic 20J


Questions Make Sankey diagrams for the following on graph paper. Highlight the useful energy. Leave the right hand side of the graph paper empty.1. Light Bulb

input: Electrical 200Joutput: Light 30J, Heat 170J

2. Fireinput: Chemical 200Joutput: Heat 150J, Light 30J and Sound 20J

3. Drill input: Electrical 1000Joutput: Kinetic 300J, Sound 200J, Heat 500J

4. Computerinput: Electrical 250Joutput: Sound 50J, Light 100J, Heat 80J and Kinetic 20J


Energy Efficiency• Definition:

• The amount of energy transferred usefully.• Can never exceed 1 or 100%.

• Equation: • Efficiency = useful energy out

total energy in• It has no Units• It can be a %


Example A TV Supplies 50J of heat energy, 50J of sound

energy, and 100J of light energy. a) What is the useful energy out?

b) What is the total energy in?

c) Calculate the efficiency of the TV?


Whiteboard Questions


Questionsa) What is the useful energy out?b) What is the input energy in?c) Calculate is the efficiency?1. Light Bulb

input: Electrical 200Joutput: Light 30J, Heat 170J

2. Fireinput: Chemical 200Joutput: Heat 150J, Light 30J and Sound 20J

3. Drill input: Electrical 1000Joutput: Kinetic 300J, Sound 200J, Heat 500J

4. Computerinput: Electrical 250Joutput: Sound 50J, Light 100J, Heat 80J and Kinetic 20J


Electrical(total in)

Heat(wasted)

Light(useful)

200 J 170J

30J

a) useful energy out = 30Jb) total energy in =200Jc) Efficiency = useful

total=30

200=0.15 or 15%

1) Light Bulb


Chemical(total in)

Heat(useful)

sound(wasted)

200 J

150J

20J

a) useful energy out = 150 + 30=180 J

b) total energy in =200 Jc) Efficiency = useful

total=180

200=0.9 or 90%

2) Fire

Light(useful)

30J



Kinetic(useful)

Heat(wasted)

1000 J

300J

500J


total=300

1000=0.3 or 30%

3) Drill

Sound(wasted)

200J



Sound(useful)

Heat(wasted)

250 J

50J

80J


total=170

250=0.68 or 68%

4) Computer

Light(useful)

100J

Kinetic(useful)

20J


Multiple-choice quiz


Anagrams


Efficiency recapAim: To create sankey diagrams To calculate efficiency

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