Few students use the Voltage-Resistance-Current (VRI) model of a series circuit
Misconception
Few students use a model of a series circuit as a system in which an agent (whose strength is measured in volts) causes an electric current around the circuit, the size of which is also determined by the resistance of the circuit (the VRI model).
Diagnostic Resources
The following worksheets may help to identify whether students hold this particular misconception.
For more information, see the University of York EPSE website.
This very open-ended question may be useful for probing whether pupils really appreciate that current is a dependent variable, whose value depends on what is connected in the rest of the circuit.
EPSE Voltage, Resistance and Current Q25The following group of questions explore pupils' ideas about what happens when the resistance of a circuit is altered by adding components in series.
EPSE Voltage, Resistance and Current Q26This question is a more open-response item probing ideas similar to those probed by the previous group of question: that current gets less when resistance is increased by adding a second (or third) component in series with the first.
EPSE Voltage, Resistance and Current Q33This open-response question probes whether pupils can use their understanding of voltage, resistance and current to explain a familiar phenomenon: that two bulbs in series are dimmer than one alone, but two in parallel are almost as bright as one alone.
EPSE Voltage in Parallel and Series Q37Resources to Address This
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Relationship between Current and Voltage and Resistance (11-14)
Source - SPT / El03PN02
This resource offers teacher some guidance on how to successfully disentangle the concepts of electric current, voltage and resistance for students.
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Simple measurements and calculations (14-16)
Source - SPT - Ee01YA05
Introduce a number of circuits where the goal is to find the effective resistance of the circuit. Students need to choose where to put the ammeter and voltmeter, and then transfer their choice and readings to the calculations templates.
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Measuring resistance with a voltmeter and an ammeter (11-16)
Source - Practical physics/ Electric circuits and fields/ Ohm's Law and resistance/ ...
This series of experiments should give students practice in taking a pair of current and potential difference readings for various components so that the resistance of the component can be calculated from V/I = R.
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Episode 108: Resistance (16-19)
Source - TAP / Electricity / Electrical resistance / ...
The idea of resistance should be familiar (although perhaps not secure) from pre-16 science course, so there is no point pretending that this is an entirely new concept. A better approach is to draw out what they know. The aim of this first episode is to provide a quantitative definition for resistance
( R = V / I) which reinforces the qualitative notion that more resistance means less current. In addition, we will look at Ohm’s law, which is not the same thing as the definition of resistance.
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References
The following studies have documented this misconception:
- Liégeois, L.; Chasseigne, G.; Papin, S. and Mullet, E. () Improving high school students' understanding of potential difference in simple electric circuits. International Journal of Science Education, 25 (9)
1129-1145.
- Millar, R. and King, T. () Students’ understanding of voltage in simple series electric circuits. International Journal of Science Education, 15 (3),
339-349.
- 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.