Simple Machines

Six Simple MachinesSimple machines help us do work..Simple machines help to add force to help move something. (It is like having super powers)The six simple machines are: lever, screw, pulley, wheel and axle, inclined plane, and wedge

The Lever A lever, is one of the six simple machines for performing work. It consists of a rigid beam that can pivot on a fixed point. We call the beam the lever arm, and the fixed point is the fulcrum. A force of effort is applied at one end of the lever arm to lift a load placed at the other end. A lever can help lift a weight with less effort. Prying something loose with a crowbar is using a lever. Some machines, such as a catapult, use a lever to hurl objects.

Three Classes of Levers First-class levers the fulcrum is in the middle like a seesaw,crowbar, or balance scale. Second-class levers- the load is in the middle like a wheel barrow, or a nutcracker. Third-class levers the effort is in the middle like a broom or a rake.

First-class Lever

Fulcrum LoadEffort

ScrewA screw is an inclined plane wrapped in a spiral around a shaft. The screw is one of the six simple machines developed in ancient times.

WedgeA wedge is a device that has two or more sloping surfaces that taper either to a sharp edge or to a point. Wedges are used to split or pierce materials, and to adjust the positions of heavy objects. Knives, chisels, axes, pins, needles, and nails are wedges.

Inclined Plane The inclined plane is a device used to raise heavy loads with relatively small forces. For example, pushing a load up a ramp onto a platform requires less force than lifting the load onto the platform.Ramps and steps are forms of inclined planes.

Wheel and Axle The wheel and axle is a mechanical device used in lifting loads. It is one of the six simple machines developed in ancient times and ranks as one of the most important inventions in history. Sometimes teeth or cogs may be placed around the edge of the wheel, as in a cogwheel, or on the sprocket wheel of a bicycle.

PulleysA pulley is a wheel over which a rope or belt is passed for the purpose of transmitting energy and doing work.