Sunday, September 14, 2008

What is a screw?

What is a screw?

A screw is a kind of inclined plane wrapped around a cylinder. It is a simple machine made out of another simple machine, the inclined plane we learnt about last week. It is actually an inclined plane that winds around itself.
Compare a screw to an inclined plane and you will see the similarities as the thread on a screw goes upward to its head. A screw has ridges and is not smooth like a nail. Some screws are used to lower and raise things. eg a car jack is used to raise the car so you can change a tyre. Screws are also helpful to hold things together. Examples are a jar and a lid, a screw, and a light bulb.

No comments: