There's a direction to the electrical current. The light bulb doesn't notice this, and you have to observe carefully to realize that the motor cares, but there are many electrical devices whose function requires having the current go the right way. We stop to look at these to reinforce this part of the analogy between electrical flow and fluid flow, and also because it introduces some new devices that are fun to play with.

Materials needed for this section

• batteries *
• battery holders *
• wires with clip ends *
• light bulb and socket *
• buzzer *

Another page you might find interesting:
Why study direction of current?

Next section:Sources of electrical energy