Simple Machines

Simple Machine

A machine that makes tasks easier by changing the size, direction, or speed of a force.

Compound Machine

A machine that combines two or more simple machines to work together, such as a car jack that combines a wedge and a screw.

Purpose of Machines

Machines help make life easier by changing the size of a force, making things speed up, and changing the direction of a force.

Lever

A simple machine made of a long rigid object that pivots around a fulcrum.

1st Class Lever

A lever where the fulcrum is between the load and the effort; examples include seesaw and pliers.

2nd Class Lever

A lever where the load is between the effort and the fulcrum; examples include a wheelbarrow and a bottle opener.

3rd Class Lever

A lever where the effort is between the load and the fulcrum; examples include a broom and fishing rod.

Inclined Plane

A simple machine that allows an object to be moved over a distance by spreading out the force needed to lift it.

Mechanical Advantage

The advantage gained by using a machine to help accomplish a task; can be changed by altering the angle of an inclined plane.

Force Multiplier

A mechanism that increases force; found in 1st and 2nd class levers.

Distance Multiplier

A mechanism that allows the load to move further; characteristic of 3rd class levers.

Newton

The unit used to measure force.

Wedge

A simple machine used to separate two objects or change the direction of force, as seen in knives and door stops.

Pulley

A simple machine that uses a wheel and a rope to lift or lower objects, making tasks faster.

Load

The weight or resistance that is acted upon by a force in a machine.

Effort

The force applied to lift or move a load in a machine.

Fulcrum

The pivot point around which a lever rotates.

Wheel and axel

A simple lifting machine consisting of a rope which unwinds from a wheel on to a cylindrical drum or shaft joined to the wheel to provide mechanical advantage.

Gear

A rotating machine part having cut teeth, which mesh with another toothed part to transmit torque and motion, often changing speed or direction.

Screw

A simple machine that converts rotational motion into linear motion, consisting of a cylinder with a helical ridge.