Bulb and buzzer in series

What the Activity is for

This activity provides the opportunity for pupils to talk and think about a circuit in which there are two components (bulb and buzzer, for example) of unequal resistance. The pupils are directed to set up the series circuit and to measure the voltage across each component and relate that to the power dissipated by each component. They must then come up with an explanation for their findings.

What to Prepare

• batteries, bulbs, buzzers, voltmeters, connecting leads
• printed copies of the support sheet: Bulb and buzzer

Support sheet

What Happens During this Activity

You might introduce this activity in the following way:

Teacher: OK, so what happened with the circuit with the two bulbs in series. What were the voltage readings?

Zac: The voltage drop across the bulbs was the same.

Teacher: Good! Now in this circuit we have two components in series again, but this time it's a bulb and a buzzer. The plan is for you to set up the circuit, measure the voltage across the different parts and then figure out what's going on.