1. Without discussion, write down one fact you know about energy on a post-it note and stick it on the board….

2. 1 minute each time to create, refine and finalise a definition.
What is energy?
Think… pair… share
1 minute each time to create, refine and finalise a definition.

3. Learning Objectives
By the end of this lesson you should be able to…
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.

4. What is energy? Key ideas: There are many “forms” of energy...
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
What is energy?
Key ideas:
There are many “forms” of energy...
These can either be stores (i.e. places where energy can be kept for a period of time) or transfers (where energy is moved)
Energy is a number / calculation, we can use the idea of energy to help in calculations

5. Gravitational Potential Heat
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Light
Chemical
Sound
Gravitational Potential
Heat
Elastic Potential
Nuclear
Kinetic
Electrical

6. The nature of energy

7. Store or transfer? Learning Objectives Light Chemical Sound
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Store or transfer?
Light
Chemical
Sound
Gravitational Potential
Elastic
Heat
Nuclear
Kinetic
Electrical

8. Energy Stores (measured in J) Energy transfers (measured in W)
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Stores and Transfers
Thermal
Elastic
Gravitational
Kinetic
Chemical
Nuclear
Sound
Electrical
Light
Energy Stores (measured in J)
Energy transfers (measured in W)

9. Mass being lifted using a motor Battery is a chemical store
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Experiment
Store at start
Store at end
Mass being lifted using a motor
Battery is a chemical store
Gravitational Potential energy
Swinging pendulum
Toy car rolling down a ramp
Battery operated fan
Pull-back toy car
Lighting a candle

10. Chemical Energy  Light Energy + Heat Energy
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Law of Conservation of Energy
Energy cannot be created nor destroyed, only transformed into different types.
Example: A candle transfers chemical energy (store) into light (transfer) and heat (store) energy.
Chemical Energy  Light Energy + Heat Energy

11. Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Select the relevant energy stores at the start and the end of each process.
A ball being thrown vertically upwards
Cyclist accelerating 11

12. Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Practical Task
Task: Visit each of the stations around the room (6 in total) and complete the sheet with observations and energy forms.

13. Efficiency = Useful Energy Output Energy Input
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Efficiency
Efficiency is a measure of how “good” a device is at transferring energy into useful forms. The higher the efficiency the less energy is transferred to useless forms (e.g. heat in a filament light bulb).
We can calculate efficiency in terms of energy:
Efficiency = Useful Energy Output Energy Input

14. Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Sankey Diagrams
A Sankey diagram is a graphical way of showing how energy is transferred in a device.
The width of the arrows is proportional to the energy output, i.e. below 90% is heat.

15. Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Sankey Diagrams
Sketch a Sankey diagram for a toy car rolling down a ramp. Think about the energy store at the start.
What do you notice about the input and outputs in a Sankey diagram?

16. The Fate of All Energy Light bulb (60J in) 50J heat 10J light
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
The Fate of All Energy
Light bulb (60J in)
50J heat
10J light
Over 80% of energy transferred to non-useful heat straight away.
Remainder goes into light energy. What happens when the light strikes a surface?
Some is reflected back into the room but the majority of it is absorbed and becomes heat energy. All reflected light ends up being absorbed and therefore ends as heat!

17. The Fate of All Energy Sports Car (2KJ) 1600J heat 100J sound
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
The Fate of All Energy
Sports Car (2KJ)
1600J heat
100J sound
300J kinetic
1600J to heat straight away
100 J to sound – what happens to this?
300 J to kinetic energy, what happens to this?
Again the sound can be reflected but most is absorbed or slowly dissipated through the air – ends up as heat!
The kinetic energy heats the road surface and tyres – it too ends as heat!

18. Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
The Fate of All Energy
At each step the chemical energy input is becoming more spread out. The energy at each stage has become less useful. Within a closed system the input energy will always equal the output but in a less useful form.
All devices suffer this same problem! Even us!

19. Sankey diagram of a Power Plant
Learning Objectives
By the end of this lesson you should be able to...
Recall, and apply, the law of conservation of energy.
Explain what is meant by an “energy store” and an “energy transfer”.
State the common energy stores and transfers
Calculate the efficiency of an energy transfer using equations and Sankey diagrams.
Sankey diagram of a Power Plant

20. Return to your definition / post-it note from the start of the lesson…
Was it a misconception?