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Physics for Kids

Simple Machines

Simple Machines are basic mechanical devices for applying a force and doing work. More complex machines are made up of a bunch of simple machines.

There are 6 basic types of simple machines:


The lever is made up of a straight rigid object like a board or a bar which pivots on a turning point called a fulcrum. Levers make work easier by using leverage which multiplies the force. When you use a lever, you move a smaller force a longer distance in order to lift a load a short distance. Examples of levers include a seesaw, pliers, crowbars, and tweezers.

The lever is a simple machine used to multiply force

See the above pictures for examples of how a lever is used in a wheelbarrow and construction equipment.

Wheel and axle

The wheel and axle is another simple machine. It uses a wheel with a rod attached in the middle as an axle to help it to lift or move loads. In some cases this machine works like a lever to multiply force (like with a doorknob or a fishing reel). In other cases it is used to move objects easier such as with wheels on a bicycle.


A pulley is a type of simple machine that uses a wheel with a groove in it and a rope. The rope fits into the groove and one end of the rope goes around the load. You pull on the other end. The pulley helps you to move the load or change direction of the force.

Some examples of pulleys include cranes, flag poles, and window blinds. When multiple pulleys are used together it's called a block and tackle. Another use of the pulley is with a flat wheel and belts. These kinds of pulleys are often used in cars.

Inclined plane

An inclined plane is a flat surface with one end higher than the other. This allows for heavy objects to slide up to a higher point rather than be lifted. It is generally easier to slide something than to lift it.

Examples of inclined planes include slides and ramps.


If you put two inclined planes back to back, you get a wedge. A wedge is a simple machine used to push two objects apart.

Examples of the wedge include knives, chisels, and axes.


A screw is a special kind of inclined plane. It's basically an inclined plane wrapped around a pole. Screws can be used to lift things or to hold them together.

Examples of the screw simple machine include swivel chairs, jar lids, and, of course, screws.

Fun Facts about Simple Machines

More Physics Subjects on Motion, Work, and Energy

Scalars and Vectors
Vector Math
Mass and Weight
Speed and Velocity
Laws of Motion
Simple Machines
Glossary of Motion Terms
Work and Energy
Kinetic Energy
Potential Energy
Momentum and Collisions

Science >> Physics for Kids

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