Resistance of a wire at a constant temperature
I can describe how to investigate the resistance of a wire at a constant temperature and make scientific conclusions.
Resistance of a wire at a constant temperature
I can describe how to investigate the resistance of a wire at a constant temperature and make scientific conclusions.
Lesson details
Key learning points
- A wire heats up when a current flows and its temperature will vary over time.
- A water bath helps to keep the temperature of a wire constant.
- Turning a circuit on for a very short time reduces the heating effect in a wire.
- In electricity investigations, it is often easy to take lots of readings rather than a few, repeated readings.
- The resistance of a wire is directly proportional to its length, at a constant temperature.
Common misconception
Pupils may not realise that the resistance of a wire varies with temperature.
Ensure pupils are aware that the temperature of a metal wire does affect resistance and that precautions should be taken to avoid a temperature change.
Keywords
Independent variable - the variable that the person doing the experiment changes
Dependent variable - the variable that is measured; it changes as a result of varying the independent variable
Control variable - a variable that needs to be kept the same to allow a fair test to be carried out
Random error - a type of error that affects results in an unpredictable way
Directly proportional - describes the relationship between two variables if both increase in the same proportion as each other
Equipment
Nichrome wire, crocodile clips, electrical leads, metre ruler, voltmeter and ammeter.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
V
Ω
A
a variable that needs to be kept the same in a fair test
the variable that is measured to get a set of results
the variable that the experimenter selects values for
$$y$$-axis
does not appear on the graph
$$x$$-axis
Exit quiz
6 Questions
