Electrical resistance
I can compare the electrical resistance of different components using measurements of current.
Electrical resistance
I can compare the electrical resistance of different components using measurements of current.
Lesson details
Key learning points
- An ammeter measures current in amps (A).
- Resistance is a measure of how difficult it is for a current to flow.
- Resistance is measured in ohms (Ω).
- In a fair test, only the independent variable is changed so that no other variables affect the results.
- The variables that are deliberately kept the same are called control variables.
Common misconception
Current is used up (consumed) by electrical components.
Use the rope–loop model to model how the battery (hands) force current (rope) around the circuit against the resistance of components (hands squeezing the rope).
Keywords
Resistance - Resistance is a measure of how difficult it is for a current to flow through a component or a circuit.
Ohm (Ω) - The unit of resistance is the ohm (Ω).
Ammeter - An ammeter is a device that measures the current flowing through a circuit.
Amp (A) - The unit of current is the amp (A), which is short for amperes.
Control variable - A control variable is one that must be kept the same when other variables are being tested to ensure that the test is fair.
Equipment
A collection of components with suitable resistances, resistors, 1.5 V and 6.5 V bulbs, pencils with both ends sharpened, leads, crocodile clips, 1.5 V cells and ammeters.
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).
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