Simple machines use energy to make work easier. These six simple tools--the lever, inclined plane, wheel and axle, screw, wedge, and pulley--have no moving parts. When combined, simple machines are the basis of all compound machines.

Inclined Plane

Science author Sally Walker defines an inclined plan as a flat surface that is raised at one end. Lifting heavy objects is made easier by sliding objects up or down this simple machine. A ramp is a common inclined plane.

Wedge

The smooth, pointed edges of the inclined plane create a second simple machine called the wedge. Elementary science texts teach that the wedge, a type of inclined plane, is used to push things apart. The blade of an axe is a common wedge.

Screw

The inclined plane is the basis of a third simple machine, the screw. Sally Walker uses a hands-on classroom lesson to demonstrate this to children. A triangular shaped piece of paper is outlined in black and then wound around a pencil to represent the grooves on a screw clearly showing how the inclined plane is found on the screw. The screw wedges into wood or metal to attach one material to another.

Lever

The lever makes it easier to pull or pry objects. Digging weeds with a hand shovel, pulling a nail out of a board with the claw end of a hammer or opening a bottle of soda are possible because of the lever. All levers have an "arm" that pivots or turns against a "fulcrum" or point, prying objects loose.

Wheel and Axle

The wheel and axle is another type of lever. The wheel is the round end and the axle is the cylindrical post on which the wheel rotates. As wheels rotate, objects can travel distances more easily. Bicycles, cars, wagon and merry-go-rounds are examples of the wheel and axle.

Pulley

The wheel and axle is the basis of the sixth simple machine, the pulley. A cord is wrapped around a wheel and attached to the object to be lifted when making a pulley. Pulling on the cord either raises or lowers the object while demanding less human energy. Flagpoles and buckets that are used to hoist water from a well are two examples.

Source:

Simple Machines

Simple Machines Learning Site

Resource:

Simple Machines Children's Book Series