Electrical Circuit
Electricity and Magnetism

Adding bulbs to the circuit

Classroom Activity for 11-14 Supporting Physics Teaching

What the Activity is for

What happens when bulbs are added?

Through practical activity, the pupils establish that when an extra bulb is added to a simple electric circuit, the current around the circuit decreases in strength and the bulb gets dimmer. They are then encouraged to make sense of their measurements.

What to Prepare

  • batteries
  • bulbs
  • ammeters
  • connecting leads
  • support sheet: Adding bulbs to the circuit (see below)

What Happens During this Activity

The pupils work in pairs to measure the current through the circuit with one, two and possibly three bulbs and observe what happens.

Then pupils are encouraged to talk and think about the electric circuit model and teaching model to account for what they have found with the various electric circuits.

The pupils first of all work in pairs to talk through their ideas to explain why the bulbs are dimmer and the current smaller when a second bulb is added. Pairs then report back during class discussion.


Download the support sheet / student worksheet for this activity.

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