1. What is it and where does it come from?
Electricity
What is it and where does it come from?

2. Be safe around electricity
Electricity can be very dangerous. You should never put anything into electric sockets, except plugs.
Never touch appliances, wires or electrical switches with wet hands or feet.

3. The movement of electric charges from one place to another is called an electric current.
When electric current flows without a controlled pathway it can be very dangerous!!
When electric current flows through a light bulb or a t.v. in our homes it is passing through a controlled pathway called an electric circuit

4. Electric circuits are used to convert electrical energy into other forms of energy that we need. Any device that converts electrical energy into another form is called a load.
Load: Converts Electrical Energy into:
Light bulb  light energy
Radio  sound energy
Stove  thermal (heat) energy

5. Make a list of the materials (parts) needed to make a light bulb light and control it:

7. Sources of electricity
There are many sources of electricity such as:
Fossil fuels: coal, oil and wood.

8. What is electricity and how is it made?
Electricity is a kind of energy.
Electrical energy is the energy provided by the flow of electrons in an electric circuit
It is made in power stations.
Electricity is also made in batteries.
How do you think electricity is connected to our homes?

9. Your Work
p. 508 #4,5
p. 510 #2, 3, 6
Tomorrow we will look at different types of renew able energy.

10. Making and Using Energy
Assess the pros and cons associated with the production of energy from both renewable and non-renewable resources.

11. How mains electricity works
The electricity produced in power stations is carried through wires into buildings.
This is called mains electricity
and we can connect to it by using a plug.

12. How batteries work
Inside a battery are two different chemicals. When you put a battery into an appliance a circuit is made.
The two chemicals begin to change into new chemicals. As they change an electrical current flows along the circuit making the appliance work.

13. Why do we need electricity?
In the modern world we rely on electricity for nearly everything.
We need it for important things like:
lighting
refrigerators
heating
What type of electricity do these appliances use?

14. What is an electric current?
An electric current is a flow of microscopic particles called electrons flowing through wires and components. - +
In which direction does the current flow?
from the Negative terminal to the Positive terminal of a cell.

15. There are two types of current electricity:
Direct Current: Current flows in one direction around the circuit. Cells (batteries) provide direct current (DC) – 1 direction
Alternating Current: Current alternates directions. Electrical generating stations that provide alternating current (AC) – Switch directions

16. 9I Energy and electricity
Power stations

17. Our electrical energy is generated in power stations.
9I Energy sources
Our electrical energy is generated in power stations.
To generate electricity we need a supply of energy – an energy source.
These devices all generate electricity. Where does their energy come from?
energy source:
gravitational potential energy from water stored high up
kinetic energy from the wheel turning
chemical energy in coal
light energy from the Sun
kinetic energy in moving air

18. What happens at a coal-fired power station?
9I What happens in a power station?
What happens at a coal-fired power station?
Click on the numbers to build up an energy chain.

19. 9I Wasted energy
The coal at a power station has stored chemical energy. But not all this energy leaves as electrical energy.
LATEST ENERGY NEWS
Energy cannot be created or destroyed – but it can be transferred.
Some energy is wasted along the way, as heat or sound energy. Does this mean the energy disappears?
The wasted energy does not disappear. It spreads out or dissipates through the surroundings. We cannot collect it and use it once it has been dissipated.

20. 9I Wasted energy
How much energy is wasted at each energy transfer in the power station?
kinetic energy  electrical energy 8%
chemical energy  heat and kinetic energy
45%
kinetic energy  kinetic energy
12%
boiler
generator
turbine 3%
electrical energy transferred
steam

21. Coal is burned to form steam, which turns the turbines.
9I Wasted energy
Coal is burned to form steam, which turns the turbines.
The steam is collected and sent to the cooling towers. Here it condenses to water again. This water will be heated to form steam again, and so on….
How much energy do you think is wasted here?

22. Generating Current Electricity
Research Project