Measurements to determine power: parallel connections

What the Activity is for

Making measurements gives a real connection to the quantities involved. The trail from these measurements to the final quoted value is a trail of evidence that should be laid out in such a way that others can see that the case is believable. Inevitably this shouldn't involve too many short cuts.

What to Prepare

• some cells and batteries, 1.5–6 volt
• some electrical wires
• a well-designed ammeter
• a well-designed voltmeter
• a collection of lamps and resistors to match the batteries and meters
• printed copies of the support sheet

What Happens During this Activity

Introduce a number of circuits containing only parallel connections, where the goal is to find the power dissipated in each element of the circuit and therefore the power dissipated in the whole circuit. Students need to choose where to put the ammeter and voltmeter, and then transfer their choice and readings to the calculations templates. As with writing templates, the idea here is to encourage good practice and that students should eventually lay out their calculations by themselves. The templates are there to act as prototypes of clear communication.