A look at how three different voltages affect the brightness of a board of light bulbs. First, the light bulbs are lit using a single battery. The current and voltage are too small to light the bulbs. In the second attempt a larger 12V battery is used. The bulbs do light up, but the light is dim. Finally, the switch is connected to 240V from the mains and the bulbs are brightly lit.

This clip is from:
Science Clips, Changing Circuits
First broadcast:
11 October 2007

Could be used as a plenary to a circuit investigation and provide a discussion point as to what is happening in the clip and why it could relate to the pupils' own circuits in the classroom.