# Students often consider the behaviour of a circuit in terms of current and much less often in terms of potential difference

Electricity and Magnetism

Misconception

• Voltage - an activity (11-14)

Source - SPT / El03TA01

This practical activity has students taking measurements of voltage using a voltmeter at various points around a series circuit. This can help develop an understanding of how varying the voltage affects the circuit behaviour.

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• Predicting and Measuring Voltages

This practical activity, aimed at slightly older classes, encourages students to predict voltage measurements and associated circuit behaviour before they take measurements using a voltmeter. This can facilitate an improved understanding of the role of voltage in electric circuits.

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• Starting to understand potential difference (11-14)

Source - SPT / El03PN14

The voltmeter is connected across the circuit component (battery or bulb) in order to measure the energy shifted for each coulomb of charge passing through the component. It measures the energy shifted each time one unit of charge passes through the component.

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• Potential difference (14-16)

Source - SPT / Ee01PN07

Energy is shifted wherever there is a potential difference, so identifying these differences is useful. Measure the potential difference from a chosen zero (usually the negative terminal of the battery or cell in simple circuits).

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• Hill diagram as a model for potential difference  (11-16)

Source - Practical physics / Electric circuits and fields/ Guidance/ ...

Scientists often speak of a coulomb ‘falling through’ so many volts and transferring so much electrical energy. That is rather like a 1 kilogram rock falling through so many metres.

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## References

The following studies have documented this misconception:

• Dupin, J. J. and Johsua, S. () Conceptions of French pupils concerning electric circuits: Structure and evolution. Journal of Research in Science Teaching, 24 (9),

791-806.

• Engelhardt, P. V. and Beichner, R. J. () Students’ understanding of direct current resistive electrical circuits. American Journal of Physics 72 (1),

98-115.

• Koumaras, P.; Kariotoglou, P. and Psillos, D. () Causal structures and counter‐intuitive experiments in electricity. International Journal of Science Education, 19 (6),

617-630.

• Guth, J. () An in-depth study of two individual students' understanding of electric and magnetic fields. Research in Science Education, 25 (4),

479-490.