Lesson 2

Showing energy changes

BACK to year 8 home learning

Objectives:

Be able to draw a Sankey diagram
Be able to use a Sankey diagram to calculate energy changes

PART A

Watch this video experiment. It involves energy changes - magnetic and kinetic energy. And no, don't try this at home!

PART B

Read and copy this sentence about showing energy changes.

We can show a conversion from one form of energy to another on a Sankey diagram. This shows how much energy is changed into each new form.

PART C

Copy this diagram and the writing onto your paper.

Sankey.png

PART D

Watch this video again - just watch from 16 minutes and 18 seconds. (16:18)

PART E

Watch this video of the clockwork toys. What energy change is happening here? (you don't need to write down your answer).

PART E

Draw this energy change for the clockwork toy on paper (you don't need to draw the toy).

energy change 1.png

PART F

Now copy this Sankey diagram for the toy. Copy the writing and labels too.

energy change 2.png

PART G

Now copy this:

energy change 3.png

PART H

Copy these out and work out the missing energy in each one.

Head phones 200J Electrical energy ----> 190 J Sound energy + ? Heat energy
Car horn ? Electrical energy ---> 450 J Sound energy + 50 J Heat energy
Car engine 20000 J Chemical energy ---> 18500 J Kinetic energy + 1000 J Heat energy + ? Sound energy
Collision 18500 J Kinetic energy ---> 16000 J Sound energy + ? Heat energy

PART I

Check your answers by scrolling down this document.

Energy changes answers

PART J

We can draw Sankey diagrams accurately on graph paper to show the amount of energy in each part of the transfer. (You don't have to copy or print this diagram).

sankey 4.png

PART K

Try this quiz to finish.

End of lesson

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