PURPOSE: To demonstrate the effect of series and parallel connections of two identical light bulbs.

DESCRIPTION: Two light bulbs can be wired in series or in parallel across 110 VAC circuit. Using 75 watt and 150 watt bulbs, ask your students which bulb will be brighter when they are wired in series, or whether they will be the same brightness. Turn on switch to activate light bulbs after setting patch wires.

Use two 25 watt bulbs to show that the brightness of each is less when they are connected in series.

SUGGESTIONS: See Question of the Week #27 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 5F20.50)

EQUIPMENT: Two 25 watt bulbs, 75 watt amd 150 watt light bulbs mounted on box with switch.

SETUP TIME: None.