PURPOSE: To generate thought about how a motor works.

DESCRIPTION: A 1.5 volt motor and 1.5 volt light bulb are wired in series such that a 1.5 volt battery can be connected across either of them individually or across both in series. An mpeg video shows what happens when each is connected to the battery individually. What will happen when both are connected in series? Will (a) only the light bulb operate, (b) only the motor operate, (c) both operate, or (d) neither operate? A second mpeg video reveals the solution.

SUGGESTIONS: Ask your students to think about this before you do the experiment.

See Question of the Week #37 for information on using this demonstration to enhance class involvement. See also Question of the Week #120 and Question #196.

REFERENCES: (PIRA unknown.)

EQUIPMENT: Pre-assembled circuit as photographed.

SETUP TIME: None.