4-ELC-02

Outcomes

• Pupils can explain how changing resistance changes current
• Pupils can link voltage, current and resitance

Specification References

• 2.12 describe the qualitative effect of changing resistance on the circuit on the current in a circuit
• 2.15 recall and use the relationship between voltage current and reistance V=IR

Starter

Give pupils white boards ask them to draw a standard test circuit - i.e. a circuit which they can use to test any standard component (e.g. a resistor). Pupils should include a power supply, ammeter (in series), a test component (e.g. a resistor), voltmeter (in parallel around the test component). For bonus marks ask them to identify the positive terminal of their supply

Main Body of Lesson

• Invesitgate three different resistors (10 ohm, 20 ohm and 30 ohm), plot an I-V graph, find the gradient, make conclusions
• Make a 10 ohm resistor - classic. Give pupils a length of wire and ask them to make a 10 ohm resistor - either use trial and error (quick method) or plot graph of resistance against length and read off ideal value. USe the PASCO kit to find the winner. Award prize if you are feeling generous.

Plenary

Look at rearranging the V=IR equation. What happens if we increase...

Additional Information

Resources Required

12x the following:

• 5V power supplies
• 10 ohm resistor
• 20 ohm resistor
• 30 ohm resistor
• simple ammeter
• simple voltmeter
• PASCO I-V sensor
• length of wire for 10 ohm resistor challenge
• wooden block to wind wire on
• 2 x croc clips