Revision as of 04:30, 13 May 2008

Outcomes

• Pupils can plan a Current-Voltage investigation
• Pupils can select the correct equipment and use an appropriate circuit to take valid measurements

Specification References

2.14 recall and use the relationship between voltage, current and resistance: voltage = current × resistance

Starter

Pupils to design a circuit to design a circuit from:

a power supply, a variable resistor, an ammeter, a voltmeter, some sample wire

Pupils to consider how to make the experiment as accurate as possible

Main Body of Lesson

Planning:

• Identify what factors could affect resistance of a wire (length, csa, material, temperature)

• Discuss how to make the experiment fair (control variables) and accurate (several values of V and I)

Observation:

• Pupils to investigate how length affects resistance (use the thickest wire)

• Pupils to investigate how csa affects resistance

• Pupils to record their results on preprtinted table to save time

Plenary

• Pupils to summarise thier findings in two simple tables (length and average resistance, area and average resistance) and discuss their findings in general as a group. This will need to be finsihed prior to the following lesson for data analysis

Homework

• Finish any unfinished tables
• Research the concept of resistivity and find the resistivities of the following:

iron, copper, constantan, nichrome, silver, gold,

• Beware the following page: resistivity on wikipedia

Additional Information

Resources Required

• Class set of power supplies, simple ammeters, simple voltmeters, variable resistors (small value), wire boards, croc clips

Textbook References

Website References

Skills Addressed

Safety/Hazards

• Thin wires can get quite hot

Notes