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WriteWriteENERGY TYPES TRANSFERS AND EFFICIENCY

Decode the Hieroglyph to find the title of todays lesson

Learning Learning IntentioIntentio

nnENERGY TYPES, TRANSFERS

AND EFFICIENCY

ENERGY TYPES, TRANSFERS AND EFFICIENCY

Learning objectivesLearning objectives

All(must)

Identify the main Types of EnergyIdentify the main Types of Energy

Show how energy can be transferredShow how energy can be transferred

Explain what efficiency isExplain what efficiency is

Be able to calculate efficiencyBe able to calculate efficiency

Most(Should)

•Generate you own energy transfer diagrams

•Explain why it is important to make machines more efficient

•Explain why efficiency is important

Some(could)

Manipulate the efficiency formula to calculate energy

Relate efficiency to energy consumption

Thursday 20 April 2023

TEHAGIHLTSDUNOHICEAMLCTECLRICAELELICASTEITKINCAVITARTIONGAL

HEATLIGHTSOUNDCHEMICALELECTRICALELASTICKINETICGRAVITATIONAL

There are 8 different TYPES of energy, can you remember what they are? UN-Jumble the words to reveal the eight different types

CONSERVATION OF ENERGYENERGY IS NEVER MADE OR DESTROYED IT SIMPLY CHANGES FROM ONE TYPE TO ANOTHER

Electrical Energy

Electrical Energy

Electrical Energy

Electrical Heat

So

un

d

ENERGY IN

USEFUL ENERGY OUT

WASTED ENERGY

Useful sound energy

Useful kinetic energy

Useful heat energy

Wasted light energy Wasted heat

energy

Wasted heat energy

Other examples

1) This kettle is 80% efficient- what does that mean?2) How can you make the Kettle MORE efficient?3) Why is important to make the kettle more efficient?

Activity Useful energy transfers

Wasted energy transfers

A    

B    

C    

D    

E    

F    

Useful and wasted energy

What are the useful and wasted energy transfers in these activities?

Use the cards and energy types provided to work out the energy transfers from these examples

Learning Learning IntentioIntentio

nnENERGY TYPES, TRANSFERS

AND EFFICIENCY

ENERGY TYPES, TRANSFERS AND EFFICIENCY

Learning objectivesLearning objectives

All(must)

Identify the main Types of EnergyIdentify the main Types of Energy

Show how energy can be transferredShow how energy can be transferred

Explain what efficiency isExplain what efficiency is

Be able to calculate efficiencyBe able to calculate efficiency

Most(Should)

•Generate you own energy transfer diagrams

•Explain why it is important to make machines more efficient

•Explain why efficiency is important

Some(could)

Manipulate the efficiency formula to calculate energy

Relate efficiency to energy consumption

Thursday 20 April 2023

Calculating EfficiencyCalculating Efficiency

Efficency =Energy out (Eout)

Energy in (Ein)

Eout

Eff X Ein

1. Calculate the Efficiency of a machine that produces 300 J of Energy for every 500J put into it

Eff = Eout / Ein

Eff = 300 / 500

Eff = 0.6

1 mark1 mark

1 mark1 mark

1 mark1 mark

Total 3 marksTotal 3 marks

Eff=500J 300J

200J

0.6 × 100 = 60%

200,000J 180,000J

20,000J

TOTAL ENERGY IN

USEFUL ENERGY OUT

WASTED ENERGY

Energy out Energy in Effficiency

30J 120J

50 J 500 J

20 J 1000J

300 J 0.6

900J 0.45

500J

0.02

0.1

0.25

Calculating Efficiency -Your turnCalculating Efficiency -Your turn

405J

Level 6 and 7Efficiency = (useful energy out/total energy in) x 100Efficiency questions 1) Name two types of useful energy given out by a hairdryer.2) A hairdryer wastes 376J for every 1500J of electrical energy it uses. How efficient is the hairdryer?3) If something is 50% efficient, how many joules of wasted energy will there be if 750J of energy is put in?4) A wind turbine has an efficiency of 52%. How much kinetic energy from the wind is needed to produce 800J of electrical energy?5) Below is a Sankey diagram; a visual representation of efficiency.

a) What’s the efficiency if the object is a room heater?b)What’s the efficiency if the object is a lightbulb?c)draw your own Sankey diagram for a kettle, which converts 400J of electrical energy. 10J is converted to sound. 300J is converted to heat and the rest is lost as kinetic energy as the kettle vibrates and wobbles. D) What is the efficiency of this kettle?

ANSWERS Thermal and Kinetic74.9 % (accept 75%)375J1538.46J 

90%10%Sankey diagram should be to scale with three arrows coming off, all labelled correctly75%

Why is efficiency so important?

Pick any object that uses energy, and produce a short presentation about it

Say what it’s energy transfers are

Why it is important to make it MORE efficient

What could happen in the future if we don’t make it more efficient?

Relate Efficiency to energy consumption

Summarise why efficiency is important

Use the following Key words in your presentation:•Energy In •Energy Out•Transfer•Efficiency•Wasted Energy•Conservation•Consumption (usage)

One thing I learned:

One thing I found difficult:

A question:

Exit ticket

9Ia(7)

Efficient cars?

1 Write down two advantages of using electrically powered cars.2 A How efficient is a normal car engine? (Hint: What percentage of energy is converted into useful energy?)b Imagine that you start with 100J of energy stored as chemical energy in the fuel in a car. How much of this energy will be usefully transferred by the engine?3 A How efficient is a power station?b If you started with 100J of energy in the fuel for a power station, how much useful electrical energy would it produce?4 How efficient is an electric car, if you include generating electricity at a power station? (Hint: An electric motor is 75% efficient. Multiply your answer to question by 0.75 to give you the overall efficiency.)5 A Which is truly the most efficient: an electric car or a normal car?

b Draw Sankey diagrams to represent the energy transfers in both types of car.6 Why does a car that runs on only fuel cells have a similar overall efficiency to a car that runs on petrol?7 Your uncle is thinking of buying a new car that is more efficient, so he will save energy. Write a letter to him, explaining why it might be more efficient to keep the car he has.

Electric cars do not have to use batteries. A fuel cell can use hydrogen and oxygen to produce electricity and is very efficient. The only substance that fuel cells give out is water (formed from the hydrogen and oxygen) so they do not cause pollution. Oxygen and hydrogen can be made from water by electrolysis, so electricity must be generated to get the hydrogen and oxygen for the fuel cell. Using fuel cells will only help the environment and save energy resources if renewable resources can be used to generate this electricity.A lot of energy is used when cars are made. It takes about 10 times as much energy to make a new car as the car will use up in fuel.Most cars use engines that run on petrol or diesel. These cars waste 75% of the energy in the fuel and produce waste gases that cause global warming and pollution. Car manufacturers are working to develop more efficient engines but they will only be able to change the efficiency by a few percent.Many people think that we should use electric cars. Electric motors are quieter and only waste about 25% of the energy they transfer, so they should help us to save energy resources. At present, special batteries for cars take a long time to charge and cannot store enough energy for cars to travel long distances but it should not be long before better batteries are developed.But where does the energy come from that charges up the battery? The electricity has to be generated in a power station. Most power stations burn fossil fuels and waste about 65% of the energy they transfer. However, it may be possible in the future to generate more electricity using renewable resources.

9Ia(2)Energy circus 1?

C Hand fan1 What is the energy store used by the fan?2 What is the final energy store?3 Describe the energy transfers in as much detail as you can.

A Moving toy1 What is the energy store used by the toy?2 Think about the time when the toy is speeding up. How is the energy transferred? Explain your answer.3 Which form of energy in your answer to question 2 is the useful form of energy?4 Once the toy is moving at a steady speed, what are the energy transfers?

B Electric fan1 What is the energy store used by the fan?2 What is the final useful energy store?3 What is the final wasted energy store?4 Describe the energy transfers in as much detail as you can.5 Draw a Sankey diagram to represent the energy changes in the fan.

D Electric bell or buzzer1 What is the energy store used by the bell or buzzer?2 How is energy transferred from the bell or buzzer to the surrounding air?3 What happens to this energy transfer as you get further away from the bell or buzzer? Why does this happen?4 What is the final form of the energy transferred by the bell or buzzer? (Hint: think about what your answer to question 2 means in terms of particles and their movement.)

E Heater1 What is the original energy store used by the heater?2What is the final energy store?3Which energy store is wasted energy?

TV

Car

BICYCLE

WALKING (ON THE FLAT)

CLIMBING STAIRS

WIND TURBINE

Electrical

He

at

Sound

Light

Electrical

He

at

So

un

d

Chemical

Kinetic

Kinetic

So

un

d

Kinetic

He

at

Chemical

Heat

So

un

d

Kinetic

Chemical

He

at

Kinetic

Gravitational

Kinetic

So

un

d

Electrical

So

un

d

He

at

HEAT

CHEMICAL

GRAVITATIONALKINETIC

ELECTRICAL

SOUND

LIGHT

HEAT

CHEMICAL

KINETIC

ELECTRICAL

SOUND

CHEMICAL

SOUND

SOUNDSOUND

HEAT

HEAT

HEATHEAT

KINETICKINETIC

KINETIC

YES I have enjoyed the lesson and learnt a lot and completed my class activity.

SOME I have understood some of the work and haven’t finished it all

NO I have found it difficult to learn today and I have done very little work

Science Department Marking your work

StrengthSay what you have done well

TargetThis is something that you could do to improve

your work and/or take the next step forward.

Efforta comment about your overall effort here.

Sometimes this will be a number.1- Excellent 2 – Good effort 3 – Satisfactory 4 - More effort

needed

Pupil commentwrite your own pupil comment.It should show how well you think that you

have understood the work.