1. Circuits

2. The Cell
The cell stores chemical potential energy and transfers it to electrical energy when a circuit is connected.

3. When two or more cells are connected together we call this a battery.
The cells chemical energy is used up when the terminals are dissolved.

4. Electric Current
An electric current is a flow of microscopic particles called electrons flowing through wires and components.
Christmas lights-one stops, all stop A
In which direction does a current flow?

5. Simple Circuits
Here is a simple circuit. It has a cell, a lamp and a switch.

6. When the switch is closed, the lamp lights up
When the switch is closed, the lamp lights up. This is because there is a continuous path of metal for the electrons to flow around.
If there were any breaks in the circuit:
the electrons would stop flowing.

7. Would this work?

8. Would this work?

9. Would this work?

11. Speaker

12. Electric Circuits
Series Circuit
Parallel Circuit 

13. Series circuit
Christmas lights-one stops, all stop

14. Series Circuit
The components are connected end-to-end, one after the other. They make a simple loop for the current to flow around.
If one bulb 'blows':
they all 'blow'!

15. Parallel Circuit  
Bathroom lights: One stops, the rest work

16. Parallel Circuits
The components are connected side by side. The current has a choice of routes.
then the others do not 'blow'.
If one bulb 'blows':

17. Measuring Current
Electric current is measured in amperes using an ammeter in series in the circuit.

20. Measuring Voltage
The 'electrical push' which the cell gives to the current is called voltage. It is measured in volts on a voltmeter.
Different cells produce different voltages. The greater the voltage supplied by cell, the greater the current.

21. Unlike an ammeter a voltmeter
is connected across the components.
Scientists usually use the term potential difference when they talk about voltage.

25. Electric Power Watts = Volts X Amperes Energy = Power X Time
Calculating:
Power =Voltage X Current
Watts = Volts X Amperes
Energy = Power X Time