Motors allow us to add movement to our devices. By controlling the flow of power to them we can adjust how they move (the speed, direction and a bunch of other things).
There are three main types of motor and they each work a little differently.
DC Motors (bottom left): Spin continuously. The only component of movement that you can control is the speed. We use PWM to adjust the speed of movement and wire to a PWM pin
Servos (upper left): Servos motors can be positioned exactly. We can tell the servo where we want it to move to. Typically we use a Library to hide all the complexity of these operations, and the library will let you choose a range in angles to set the position of the servo. This is normally from 0 to 180 degrees
Steppers (upper right): Steppers are moved in increments. Fluctuations the power sends a signal to the motor to move a tiny amount. You can’t position it exactly (i.e. move to 173 degrees) but unlike servos you can continuously rotate a stepper (go around and around). Some steppers can move backwards and forwards too.
Motors come in various shapes and sizes. Some motors will require higher power but they can do more - they have more torque (or can apply more force) to lift heavy objects etc. When using motors be sure to check the power requirements.
In your kits
You’ll find a few different motors:
A servo - small servo that works well with 3v power supplies is included.
A DC hobby motor - a small low power motor
A vibration motor - a small weighted motor to create vibrations