Levers and PulleysNot so simple machines!

Just think…. Could you lift your science

teacher in the air?

Keep Thinking…..(This means you don’t have to write this!!)

Building a house

Lifting a car

Building the pyramids

Handicap ramps

Paper cutters

Wheels on a car What do all of these have in common?

They are use simple machines!

Important DefinitionsMachine- device for doing work

Complex machines have motors, simple machines do not

Effort- the amount of force applied to a machine Effort is measured in Newtons (N)

Types of Simple MachinesLever

Pulley

Wheel and axle

Inclined plane

Wedge

Screw

Just Read…Simple machines have been used for thousands of years. They were even used to help build the pyramids!

LeversThe most simple and most common simple machine.

3 Parts of a lever

Class 1 Levers

Class 1 LeversThe fulcrum is located somewhere between the

effort and the load

Examples include: The claw of a hammer crowbar

Double Class 1 LeversTwo levers working together form a double

lever

Examples Include: Scissors Tin snips

Class 2 Levers

Class 2 LeversHas a fulcrum at one end of the lever arm

Examples include: Paper cutter Wheelbarrow

Class 3 Levers

Class 3 Levers In a class 3 lever, the fulcrum is at one end,

and the effort is applies between the fulcrum and the load

Examples include: Baseball bat Fishing pole Catapult

Wheel and Axle

Wheel and Axle

Wheel and AxleCan be an actual wheel and axle OR a bar that

rotates around an axis

Examples include: Steering wheel A wrench turning a bolt (see levers and pulleys

book page 7) Windlass (crank used to raise a bucket, see page

8) Handle of a faucet (page 8)

The Inclined Plane

The Inclined Plane

The Inclined PlaneA sloped, flat surface, or ramp

One-part simple machine that does not move

Pulleys

PulleysA pulley is a wheel that is free to turn on an

axle The wheel is called a sheave A pulley is considered to be a variation of the lever Pulleys can be fixed or movable