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Year 9 - Science

Electrical resistance

Resistance and parallel circuits

Unit Summary

This unit covers electrical circuits, compares appliance power ratings, and understands domestic fuel use and costs. It explores electric current, potential difference, resistance, and the differences between conductors and insulators, focusing on calculations and applications in circuits.

Lesson Summary

You will learn to compare the electrical resistance of different components using measurements of current.

Key Notes

  • 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.

Vocabulary To Learn

  • 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.

Common Mistakes To Avoid

  • Current is used up (consumed) by electrical components.

3 Quick Questions (With Answers)

1. Explain the scientific idea in this lesson using two key points.

An ammeter measures current in amps (A). Resistance is a measure of how difficult it is for a current to flow.

2. Define this scientific word and use it in context. 'resistance'

Resistance is a measure of how difficult it is for a current to flow through a component or a circuit. Include the word in a full scientific explanation, not as a single label.

3. Correct this common scientific misunderstanding.

Mistake: Current is used up (consumed) by electrical components. Correction: 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).

More Lessons In This Unit

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