The electrical charges move altogether(Challenge)



All together, in every part of the circuit

Wrong Track: When the switch is closed, the charges leave the battery and move around the circuit.

Right Lines: When the switch is closed, the charges all around the circuit are set into motion together. When the circuit is completed, the charges start moving in all parts simultaneously. Those charges in the connecting wires, just before the bulb, move through the filament wire. The store in the battery starts to be depleted and the bulb comes on with no apparent delay. It is not a case of waiting for those charges, that have just left the battery to arrive at the bulb before the bulb lights. There is a continuous and steady flow of charges in all parts of the complete circuit.

Encouraging thinking about movement everywhere in the loop

Thinking about the learning

The wrong tracks statement suggests the same incorrect idea from an earlier challenge that the charges all originate in the battery and flow out from the battery to form the electric current.

Thinking about the teaching

When talking to classes about how electric circuits work, it is natural to start with the battery, which is essential to making things happen everywhere in the loop. However, it is important to reinforce the idea that once a circuit is completed, the charges start moving in all parts simultaneously.

So, rather than pointing with one finger to trace the path of the charges as they leaves one side of the battery, it is helpful to gesture with both hands together, showing the charges simultaneously moving in opposite sides of the circuit loop. Don't always place one of the gesturing hands over the battery.





This is a nugget in the TL thread – connect all three threads from any link

Physics Narrative (PN) Teaching & Learning Issues(TL) Teaching Approaches(TA)

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