Ratchet (Screw)

This program activity and tutorial demonstrates the concept of a screw. A screw is a close relative of the inclined plane. If you take a piece of paper cut to the shape of an inclined plane and wind it around a cylinder, you will get the form of a screw. This is similar to taking an inclined plane, in the form of a road or railroad tracks, and winding it around a mountain.

A wood screw is turned by a screwdriver or ratchet and the threads advance the screw into the wood at the same time. The amount of distance the screw goes into the wood for each turn of the screw is called the pitch. Two examples are given below and in the program.

	The screw with steeper thread (higher pitch) will take more force and less turns to be turned into the wood.
	The screw with less steep thread (lower pitch) will take less force and more turns to be turned into the wood.

The amount of work done to turn the screw into the wood is the same in both cases. The simple machine screw changes the way in which the work is done: the higher pitch requires more effort and less screw turns, while the lower pitch requires less effort and more screw turns.

Ratchet (Screw)

A wood screw is turned by a screwdriver or ratchet and the threads advance the screw into the wood at the same time. The amount of distance the screw goes into the wood for each turn of the screw is called the pitch. Two examples are given below and in the program.

The screw with steeper thread (higher pitch) will take more force and less turns to be turned into the wood.

The screw with less steep thread (lower pitch) will take less force and more turns to be turned into the wood.