What the activity is for
Here you will want to concentrate on what is happening in the resistive elements of the circuit when bulbs are added to the circuits.
- Less current passes through the elements.
- The energy of each chunk of current is decreased.
What to prepare
- set of batteries, bulbs and wires, suitable for building the circuits of your choice
What happens during this activity(You might want to assume that doubling the number of bulbs in the circuit halves these quantities, as a first approximation.)
Other changes follow from this, and you may want to use the energy and charge flow descriptions as well, although these should not be central at this point. The whole circuit is important here, so we suggest building one or two simple ones, showing how the labels might be used and then providing a few challenges to construct with the class as a way of fixing the behaviour of the circuit elements in their minds.
For selected circuits, we suggest that you use a mixture of current and potential difference labels, and consider the necessary changes to these labels as the number of bulbs is increased.
Alternatively, you might seek to reinforce knowledge about the behaviour of charge flow by, for example, setting a question similar to the following:
Teacher: How can you picture the flow of charge in all of these circuits to give a fair comparison?