The wheel and axle are two totally different objects but without each other they would not be able to work correctly. Firstly, the wheel is the object at the bottom, that is round, and it helps objects roll on the ground instead of them dragging. The axle is the object that keeps the wheel(s) in place. A good example of the wheel and axle is a car. Underneath the car, there are the wheels & axles. The wheels help move the car around and decrease friction while the two axles between the front tires and the back tires connect the tires to the car. The second way in which a wheel is used is in a doorknob or a sink faucet. Inside the doorknob there is a fulcrum where the axle is. Like the pulley, it still takes as much effort to pull something around on a wheel & axle but the object does not drag on the ground and this could prevent whatever you are carrying around from getting possibly damaged.