1. Electrical
Energy in the Home

2. Drawing circuit diagrams
You must have
Straight lines
Sharp corners
Use the correct symbols

3. Circuit symbols
Light bulb

4. Can you remember….?
Component
Symbol
Battery
Wire
Bulb
Buzzer

5. Which light bulbs will light?A B D

6. A complete circuit
For electricity to flow in a circuit it must be able to flow from one end of the battery to the other end

7. Electricity does not only flow inside wires!
Lots of materials let electricity flow through them.
An electrical conductor allows electricity to flow through it.
An electrical insulator does not allow electricity to flow through it.

8. Set up the circuit shown….
Testing to see if a material is an electrical conductor or an insulator
Set up the circuit shown and place different materials in the gap in the circuit. Record which materials let electricity through (the bulb lights if electricity flows).
Set up the circuit shown….
What do we call a material that lets electricity flow through it?
CONDUCTOR
What do we call a material that does not let electricity flow through it?
INSULATOR

9. Electron Flow

10. Electron flow
Electricity in wires is a flow of electrons along the wire from the negative end of the battery to the positive end
What do we call this flow of electrons?
Electrical current

11. Voltage
The v_____ is a measure of how big a push the e_______ are given as they leave the b_____. The bigger the voltage, the bigger the p___.
oltage
lectrons
attery
ush
lamps

12. Measuring voltage
The unit of measure for voltage is the volt, symbol V.
Voltage is measured using an voltmeter. . V

13. Current ircuit lectrons ore
In an electric c____, current is the flow of e_______ carrying electrical energy. The bigger the current, the m___ electrons are flowing around the circuit.
lectrons
ore
Current is a measure of how much electrical energy is flowing in a circuit.
lamps

14. Measuring current
The unit of measure for current is the amp, symbol A.
Current is measured using an ammeter. A

15. Set up the two circuits shown:A.
BRIGHTER B.
DIMMER
In which circuit are the bulbs the brightest?
What do we call circuit B?
What happens if you unscrew a bulb in circuit B?
What do we call circuit A?
What happens if you unscrew one bulb in Circuit A?
The other bulb stays lit.
The other bulb goes out.
Series Circuit
Parallel Circuit
In circuit A the bulbs are the brightest.

16. A series circuit
All bulbs will glow dimmer!

17. Old Christmas tree lights
If one bulb breaks the circuit is broken - all bulbs go out!

18. A Parallel circuit
The bulbs all glow brightly!

19. Example:In new christmas tree lights
If one bulb is broken the other bulbs can still light

20. Think How do you think lights on a xmas tree are set up?
What about street lamps?
Lights in a car?
Lights in your house – between rooms?

21. Series circuit – 1 bulb
Series circuit – 1 bulb

22. Series circuit – 2 bulbs
Series circuit – 2 bulbs

23. Parallel Circuit
Parallel circuit

24. Resistance The symbol = R Measured in Ohms .using an Ohmmeter.
Resistance is how much a material tries to stop electricity passing through it!!!
The symbol = R
Measured in Ohms .using an Ohmmeter.

25. Experiment: How are current and voltage related as electricity flows through resistor?

26. Current-voltage graph for a resistor
The graph of current against voltage is a straight line
The two quantities current and voltage are directly proportional. x x x x
Current / A x x x x
Voltage/ A
Ohm’s Law
The voltage and the current in a circuit are directly proportional to each other when resistance and temperature are constant

27. Resistance
Resistance
Calculating resistance

28.   x V VR I = I Ohms law triangle
Whatever you are trying to find cover it up and it will leave you with the calculation that you need.
So if you are trying to find current (I)...
…which gives the formula… V  
I = VR
…cover up I… I R x

30. A bulb has a current of 20 A and a voltage of 100 V
What is the resistance?
R = V I
= 100 V
20 A
= 5 

32. The everyday uses of electricity

33. 1. The heating effect of an electric current
Applications: irons, kettles etc

34. The magnetic effect of an electrical current
Application : electric motor.

35. The chemical effect of an electrical current
An electrical current can cause chemical reactions to happen!
Application: when electricity is passed through water it breaks up into oxygen and hydrogen gas!

36. Hydrogen gas can then be used as a fuel

37. A complete circuit is required for electric current to flow
Simple Circuits
A complete circuit is required for electric current to flow
Circuits can be drawn using circuit diagrams with correct symbols
Components can be arranged in series or parallel
Simple circuits

38. Circuit Symbols
Circuit symbols

39. Switches – series circuit

40. Switches - parallel circuit

41. Drag & Drop Circuit
Drag & Drop circuit