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

The teacher could ask the children to select specific equipment to investigate which battery produces the brightest and dimmest bulb. The teacher should cover up each batteries voltage so that children do not know which is the most powerful.