Almost every household appliance that moves uses a motor. This includes computers, microwaves, phones, washing machine, dryer, fans, etc... The microwave has a turntable inside which uses a motor to produce the rotating motion (well, at least my microwave has a motor that can do that :P). We learned that motors use coiled wires and magnets. The current within the coil and the electric field inside the coil determines the speed of the motor. The spinning motion is produced because the coil feels a force created from the magnetic field of the magnet.
Turntables are just one way a motor is shown at work. The speed of the turntable can be adjusted by increasing or decreasing the amount of current that flows through the coils (in the case of the microwave).