energy and electricity

1. 11/22/14
EEnneerrggyy aanndd EElleeccttrriicciittyy
W Richards
The Weald School

2. TThhee 99 ttyyppeess ooff eenneerrggyy 11/22/14
Type 3 example sources
Heat
Kinetic (movement)
Nuclear
Sound
Light
Chemical
Electrical
Gravitational potential
Elastic potential

3. EEnneerrggyy cchhaannggeess 11/22/14
To describe an energy change for a
light bulb we need to do 3 steps:
1) Write down the
starting energy:
3) Write down
what energy types
2) Draw an arrow are given out:
Electricity Light + heat
What are the energy changes for the following…?
1) An electric fire
2) A rock about to drop
3) An arrow about to be fired

4. EElleeccttrriiccaall EEnneerrggyy 11/22/14
Consider a simple circuit:
The job of the battery is
to convert ______ energy
into _________ energy…
The job of the bulb is to
convert the _________
energy it receives from
the battery into ______
energy.
Words – electrical (x2), light, chemical

5. EElleeccttrriiccaall EEnneerrggyy 11/22/14
Energy
Hi. I’m Ernie Electron
and I’m going to show
you how I get energy
around a circuit.

6. EElleeccttrriiccaall EEnneerrggyy 11/22/14
Energy
Hi. I’m Ernie Electron
and I’m going to show
you how I get energy
around a circuit.

7. EElleeccttrriiccaall EEnneerrggyy 11/22/14 Hi. I’m Ernie Electron
and I’m going to show
you how I get energy
around a circuit.
Energy

8. FFuueellss 11/22/14
A “fuel” is something that can be burned to release heat and
light energy. The main examples are:
Coal, oil and gas are called “fossil fuels”. In
other words, they were made from fossils.

9. WWiinndd PPoowweerr 11/22/14

10. TTiiddaall PPoowweerr 11/22/14

11. WWaavvee PPoowweerr 11/22/14

12. 11/HHyyddrrooeelleeccttrriicc PPoowweerr 22/14

13. GGeeootthheerrmmaall EEnneerrggyy 11/22/14

14. SSoollaarr PPoowweerr 11/22/14

15. PPoowweerr ssttaattiioonnss 11/22/14

16. WWhhaatt ddooeess eeaacchh ppaarrtt ddoo?? 11/22/14
The boiler is where the
fuel is burnt to boil water
The steam from the boiler is
used to turn a turbine
The turbine is connected to the generator,
which acts like a dynamo – it generates
electricity out of movement
The steam is cooled down and turned
back into water in the cooling tower

17. 11/EEnneerrggyy TTrraannssffeerr ddiiaaggrraammss 22/14
Consider a light bulb. Let’s say that the bulb runs on 100
watts (100 joules per second) and transfers 20 joules per
second into light and the rest into heat. Draw this as a
diagram:
“Input” energy “Output” energy
100 J/s
electrical
energy
20 J/s
light energy
80 J/s heat
energy (given to
the surroundings)

18. EExxaammppllee qquueessttiioonnss 11/22/14
Consider a kettle:
Sound
energy
1) Work out each energy value.
2) What is the kettle’s
efficiency?
Wasted
heat
Heat to
water
2000 J/s
electrical
energy
Consider a computer:
150 J/s
electrical
energy
10 J/s
wasted
sound
20 J/s
wasted
heat
Useful
light and
sound
1) How much energy is converted
into useful energy?
2) What is the computer’s
efficiency?