3-ELE-10
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Contents
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