Simple and Compound Machines

Simple Machines

A fundamental mechanical tool that alters the amount or direction of a force to help perform work more easily.

Compound Machine

A machine made by combining two or more simple machines to perform more complex tasks efficiently

Efficiency

A measure of how well a machine converts input energy or work into useful output work without loss. More of this means less wasted energy.

Force

A push or pull that can initiate movement, bring an object to a halt, or alter its direction.

Work

Occurs when energy is transferred as a force and causes an object to move in the same direction as the applied force.

Mechanical Advantage

The ratio comparing the output force produced by a machine to the force you apply, showing how much the machine amplifies your effort.

Input Work

The work or energy applied to a machine by the user.

Output Work

The useful work or energy produced by a machine to perform a task.

Wheel & axle, lever, wedge, screw, inclined plane, pulley

6 Simple machines

Fulcrum

This is the fixed pivot point around which a lever balances, turns, or rotates.

Effort

The pushing or pulling force you apply to the lever

Load

The object or resistance you are trying to lift, move, or overcome.

Lever

A rigid bar that pivots on a fixed point called a fulcrum. It multiplies the applied force to lift heavy loads.

Inclined Plane

A sloped surface or ramp that makes it easier to raise or lower heavy objects across heights by spreading the work over a longer distance.

Wedge

Formed by two inclined planes placed back-to-back. It is used to cut, split apart, or hold objects in place (e.g., axes, knives, doorstops).

Screw

An inclined plane wrapped spirally around a central cylinder or shaft. It holds things tightly together or lifts materials (e.g., jar lids, wood screws, bottle caps).

Wheel and Axle

A wheel connected to a central shaft (axle) so that both rotate together, reducing friction and multiplying force or speed (e.g., doorknobs, bicycle wheels, steering wheels).

Pulley

A grooved wheel with a rope or cable passing over it, used to change the direction of a pulling force to easily lift heavy items upwards (e.g., flagpoles, cranes, window blinds).