Transcript Watt difference can you make?

Being energy wise
Test your knowledge of energy
use at school and at home
Learning Objectives
• To know that many everyday appliances use
electricity.
• To know that electrical appliances have power
ratings measured in watts or kilowatts.
• To know the difference between ‘power’ and
‘energy’.
• To know that, if you want to work out how much
energy an appliance has used, you need to
know its power rating and how long it is used.
Work with a partner or in a small
group….
Can you list all the electrical
appliances you use in your
classroom?
How many did you have? Did
you think of ….
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Lights
Heating
Computer
Television
Radio
Video or DVD
Tape recorder
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Battery powered toys
Fans
Clocks
Digital camera
Digital camcorder
Digital voice recorder
Telephone
What other appliances did you have?
TRUE or FALSE?
• Appliances on standby don’t use energy.
• FALSE
• Some types of light bulbs use a lot less
energy than others.
• TRUE
• Lights need to be on all the time.
• FALSE
• We can all help to use less energy.
• TRUE
So, what appliances do you
think use the most energy?
• Discuss with a partner
What appliances need lots of power to
make them work?
What appliances are used for long periods
of time?
Do all appliances need the same amount
of energy to work?
How do we measure electricity
use?
• Power – we measure the rate at which an
appliance takes power from the electricity
supply in watts or kilowatts (W or kW).
• 1 kilowatt is the same as 1000 watts.
• Look at the labels on some appliances –
which use the most power?
How long is it on for?
• Energy – we work out how much electrical
energy is used by multiplying the power of
the appliance (kW) by the number of
hours it is used for. This gives the amount
of energy used in kilowatt-hours or kWh.
• One kWh is the energy used when one
kilowatt of power is used for one hour.
Which uses the most energy?
• A 1 kW microwave oven, used for 2 hours?
• A 1 kW vacuum cleaner, used for 1 hour?
• A 3 kW kettle, used for 1 hour?
Microwave oven
1 kW x 2 hours = 2 kWh
Vacuum cleaner
1 kW x 1 hour = 1 kWh
Kettle
3 kW x 1 hour = 3 kWh
It’s the kettle – were you right?
Power and energy
Remember that 1000 watts = 1 kilowatt
If one light bulb uses 20 watts of power…..
How many light bulbs would use 100 watts?
How many light bulbs would use 1000 watts or 1kW?
If all these light bulbs were left on all day from 8 in
the morning to 6 at night, how many kWh of
electricity do they use?
How many light bulbs are in your school?
How does this help us to be
energy wise?
• What have you learnt from this?
• How could you use this information in a
lighting survey?
Where does electricity for
lighting come from?
Watch some of the international films to see how
electricity can be generated in different ways
• Where does the electricity come from?
• How do the families pay for their lighting?
• What environmental costs are there?
• Where does the electricity come from for the
lights in your home and at school?
• How does your family pay for lighting?
• What environmental costs are there?
How can we monitor how much
energy we use?
Watch the UK school films to see how pupils
are monitoring and reducing their energy
use.
Are these pupils doing things that you do
too?
Are they doing things you would like to do?
Discuss with your teacher the good ideas
that you find.