Inclined Plane, Wedge and Screw

A simple machine is a device with few or no moving parts that is used to make work easier. People have used simple machines for thousands of years. There are six simple machines. They are:

1. Inclined Plane
2. Wedge
3. Wheel and axle
4. Pulley
5. Lever
6. Screw

In this lesson we will look at the inclined plane, wedge and screw.

What is an inclined plane?

An inclined plane is a simple machine with a sloping surface. It is used to move objects to a higher or a lower level. In the picture below you can see a ramp being used by a worker. A ramp is an inclined plane.

It is easier to move an object to a higher level using an inclined plane than to lift it. Examples of inclined planes are ramps, stairs, slides and escalators.

_{The slide in the picture above is an inclined plane. The staircase on the side is also an inclined plane.}

What is a wedge?

A wedge is a simple machine which is made up of two inclined planes. It is thin at one end and thicker at the other. A wedge can be used to split or secure objects. Wedges can be made of materials like metal, wood or stone. The picture below shows a wedge made of metal.

_{Photo of a metal wedge, taken by Shakespeare and used under this creative commons license.}

Wedges are used to split or secure things. Examples of wedges are axes, knives, nails and chisels. Even your front teeth are wedges.

_{The head of an axe is a wedge. It can be used to split pieces of wood.}

_{This type of doorstop is a wedge. It is used to hold a door securely in place. (Photo by Bozembla and used under this creative commons license).}

What is a screw?

A screw is a simple machine that is made up of an inclined plane which is wrapped around a cylinder. Screws can be used to hold things together. Look at the picture of a screw below. This type of screw is used to hold things like pieces of wood together. Many machines such as computers, washing machines and refigerators are held together with many screws. A screw is also used to hold some bottle caps and jar lids in place. Also, some lightbulbs have a screw on the bottom to hold them in place. 

Screws can also be used to lift things. The device seen below is called a screw jack. It is used to lift heavy objects such as a car or even a house.