The screw is made from a cylinder and a rounded incline plane to twist and wedge it's way into the point. A screw is used to tighten, hold together, or focus pressure into a single point. The screw is used in almost every kind of machine you use daily or just for fun. Believe it or not the screw is another type of inclined plane. The way that screws are used is the sharp metal edge on the screw is used to penetrate a hole and can alow the board or whatever the materials are to move or slide or to bind and tighten together.

You'd think there are weird machines that are simple. You thought right! A world changing simple machine is the wheel and axle. Wheelbarrows and cars are examples. They are made by artistic value on the maker so they look like something that would make a worldwide phenomenon. They did, and are used mostly to transport people and things.

A Wheel and Axle is a wheel connected to a stiff stick. A Wheel and Axle is made of two disks (wheels) of different sizes that are mounted in a way that allows them to turn together around the same axis. This assembly lets you trade distance for force in a doorknob or force for distance in a bicycle.

Some examples of a Wheel and Axle are the Ferris Wheel, a toy wagon, and washing machine drum.

Wheel and Axles can be used to move objects long distances like a bus or a taxi.
Another use for the Wheel and Axle is that it can be used to open things (doorknob).