The first lab was to set up a motor running off it's own power with a TIP120 transistor. The potentiometer controls the motors speed by having the microcontroller pulse the transistor. The 9v battery is plugged into a 5v voltage regulator, which powers the motor. The arduino is powered by the USB.
The second lab involved setting up an H-bridge IC with the motor. The switch toggles between running the motor fowards and backwards.