Advantages of Simple Machines

• Describe how simple machines change the amount of force needed to do work.

• Explain how machines can decrease force by increasing the distance over which it's applied.

• Define what efficiency means for machines and the work that they perform.

• Explain the difference between simple machines and more complex compound machines.

Key Vocabulary

Simple Machine

A mechanical device that changes a force's direction or magnitude to make work easier.

Efficiency

Efficiency is how well a machine uses the energy you put in compared to the useful work it gives out.

Force

A push or a pull on an object which causes it to move or change its direction.

Compound Machine

A device that is formed when two or more simple machines are combined for greater efficiency.

How Do Machines Make Work Easier?

• A simple machine is a device that helps make any work easier.

• It changes the direction or amount of force that you must apply.

• You apply force to the machine, and it applies force to the object.

• This means you use less force to get the same job done.

Trading Force for Distance

• Simple machines let you use less force over a greater distance.

• An inclined plane helps move heavy objects upward with less effort.

• A screw is an inclined plane wrapped around a cylinder.

• This trade-off makes screws excellent for holding things together tightly.

What Are Compound Machines?

• Two or more simple machines combined form a compound machine.

• Their main purpose is to make completing work much more efficient.

• They combine simple machines to handle more complicated tasks.

• Many of the complex tools we use every day are compound machines.

• Simple machines reduce the force needed or change a force's direction to make work easier.

• Some machines trade more distance for less force, like inclined planes and screws.

• A pulley is a machine that is used to change the direction of a force.

• Compound machines are combinations of simple machines that increase efficiency.