Up Electrostatics Current & p.d. I Current & p.d. II Kirchoff's Law Ohm's Law I-V Graphs I-V Graphs II Thermistors LDRs Mains Electricity Fuses & Earth Wire Fuse & Earth Wire II

 

                                                

 

Rogue Physicist.  Free resources for physics education 2006-2016 Dorian Pascoe.  Email: dorian@top-school.co.uk

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Electricity

 

 

 

A Tesla Coil.

 

 

 

 

The electricity module covers work on charges and electrostatics, voltage, resistance, electric current in series and parallel circuits, ohmic and non-ohmic components, and mains electricity.

 

 

Details of the content and teaching order can be seen below.

 

 

 

Lesson

Learning Outcomes

Notes

1 - Electrostatics

  • Know that there are two types of electrical charges

  • Know that negative charges are small and light, and that charges can be transferred by friction.

  • Be able to describe and explain processes involving the transfer and interaction of charges, using correct technical language.

 

2 - Current & p.d. I

  • Know that  current is the rate of flow of electrons

  • Know that voltage is the energy given to these electrons.

  • Be able to select and use the equation I = Q t to solve problems involving the flow of charge in a circuit.

 

3 - Current & p.d. II

 

  • How to connect an ammeter into a circuit to measure electric current.

  • How to connect a voltmeter into a circuit to measure voltage.

  • Be able to build a simple circuit and measure voltage and current.

Students need to know that voltmeters go in parallel, ammeters in series.

4 - Kirchoff's Current Law

   

4 - Resistance

 

  • Understand the relationship between current, voltage and resistance.

  • Select and use the equation:

    Resistance = Voltage current

 

5 and 6

IV graphs

 

  • Use a circuit which includes a variable resistor to investigate how the current changes with voltage for:

  • A resistor

  • A bulb

  • A diode

 

Bulb and resistor can be done using one, two or three cells and plotting a graph with three points (not brilliant, but makes the point well enough). The diode can be done as a demo, or by using an LED with a 100ohm resistor in series. Use a rheostat to vary the voltage from 0-3V. The current is small, but just about readable using the standard grey ammeters.

7 - Kirchoff's Law

 

   

7 and 8

Mains Electricity

 

  • Describe the colours and purpose of Live, Neutral and Earth wires.

  • Understand why insulation is important for mains voltage.

  • Use the equation    Current = Power/Voltage to calculate the correct fuse.

 

Plugs for wiring - work in groups of two. One person takes plug apart, the other rewires it. Check that each plug is correctly wired before it goes back into the bag. Pupils can colour and label diagrams while their partner is working on the plug. Safety - ensure that plugs cannot be plugged in (rivet through earth pin) and turn off room supply.

9 and 10

Fuses and circuit breakers

Extended writing opportunity

 

  • Explain how the earth lead and fuse work together to protect against electric shocks.

  • Compare MCBs and RCDs to fuses.

  • Discuss how ideas about risk and cost are used to decide the mains voltage for a country.

 

Dangerous kettle man demo works on about 7V DC - get pupils to watch fuse wire and ammeter (do it twice) then write their own explanation of what is happening using key idea that the body has a high resistance so the current that flows to earth is too small to blow the fuse, whereas the earth wire provides a low resistance path to earth so the current is high. Mention double insulated - plastic body - needs no earth wire. Extended writing opportunity

 
  • Revision lesson

  • Test

  • Go over test

 

Revision quiz 1

Revision quiz 2

Student checklist