The Motor module contains a small electric motor that operates between 7V and 12V. It will operate in both directions. The direction of the motor depends on the direction of the current. Adjusting the power to the motor will adjust the speed at which it spins. However, there is not much room for down adjustment in most cases since the motor requires nearly all of the power our 9V power source can produce.
Contents and Images credit: Circuit Scribe Website