1. Electrical Devices 20 April, 201720 April, 2017 Objectives
Be able to describe examples of electrical devices and calculate the energy transformed from the definition of power.
HSW: AF3: Decide on the most appropriate method of presenting data.
Used before in:
Will use again in:
PLTS: Team Workers: collaborate with others to work towards a common goal.
Keywords:
Electrical, kinetic, sound, light, heat, power, joule, watt, kilojoules, kilowatt, transfer, transformation

2. Outcomes All students should be able to:
Give examples of devices that use electricity and describe the useful and wasted energy transformations.
Most students should be able to:
Describe what power is and give the units of Energy and Power.
Explain the advantages and disadvantages of using electrical appliances in different situations.
Some students should be able to:
Use the definition of power to calculate the amount of energy an appliance uses and give the correct units.

3. Starter: My Appliances
ALL
Starter: My Appliances
Write down all the electrical appliances you have used today in a table like below:
Use these keywords to help you: light, sound, heat, kinetic, electrical,
Appliance
Energy type(s) wanted from appliance (useful energy)
Wasted
Example: electric razor
Movement (kinetic)
Sound

4. Why is electricity an important energy resource in the home?
What different electrical appliances do you have at home?
Mixer
Fan heater
Toaster
Espresso machine
Bread maker
Kettle
Dishwasher
Freezer
Fridge
Microwave
Oven
Extractor fan
Food processor

5. Why is electricity an important energy resource in the home?
Consider my kitchen appliances again:
Freezer
Fridge
Microwave
Oven
Extractor fan
Food processor
Mixer
Fan heater
Bread maker
Dishwasher
Have a motor
Have a heater
Fan heater
Toaster
Espresso machine
Bread maker
Kettle
Dishwasher
Oven

6. Why is electricity an important energy resource in the home?
MOST
Why is electricity an important energy resource in the home?
most domestic appliances use electricity
What tasks can electricity be used for?
Heating,
Moving,
Cooling,
Lighting,
Entertainment
Task: In pairs: Discuss, then write down your answers 1 For each of the 5 tasks, come up with as many ways of doing this task without using electricity.
2 Now come up with advantages and disadvantages of these other methods compared to using electricity.

7. Electricity vs Other Resources
What are the 4 advantages?
no pollution at point of use
easy to use
can be used to operate a large variety of domestic appliances
no storage problems
What are the 3 disadvantages?
cannot be stored so risk of power cut
risk of shock
needs cables to the house- problem for remote properties
If you didn’t get these: jot them down now!

8. Power
What is power?
Power is the rate at which energy is transferred.
Power in Watts is the amount of Joules transferred in 1 second. E T P

9. Electrical Appliances Demo Time!!
SOME
Electrical Appliances Demo Time!!
Yay…
Your teacher will show you a number of devices and measure their power outputs.
Make a table to show the energy that each device has. You must label each column and use units correctly. Include a column for time and energy.
Now draw a graph. What type of graph will you draw? Explain why you have chosen the graph you have. (Hint: it depends on the type variables – continuous or categoric.)
If all the appliances were running for 60 seconds, how much energy would they use?
Differentiation: Edit this slide so that different appliances are on for different times to make more difficult etc.

10. Plenary: Big Q – Does electricity run like clockwork?
A clockwork radio uses a spring to turn a generator inside the radio to make it work. 30 seconds of winding is enough to provide 60 minutes of radio play time. It has a power rating of 10 Watts.
ALL: Describe the input energy, the useful energy and the wasted energy.
MOST: What is the advantage of a clockwork radio over a battery powered one? Where might it be used?
What is meant by “It has a power rating of 10 Watts.”
SOME: How much energy, in Joules, would it take to have the radio on for 24 hours and how long would you have to wind it for?