The train departs from Station 4 leaving you standing alone on the platform. It accelerates into the distance with the whine of its motor getting higher and higher as it speeds up. You wait for the next train.
To make the electric motor of the train go faster and faster, the driver must be causing more electricity to flow through the circuit to the motor.
How can the amount of electricity to the motor be controlled?
Introductory activity: Controlling electricity
Activity 1: Fuses
Activity 2: Light dimmer