Simple Machines

Simple machine- a device that does work with only one movement. -Machines make work easier by changing the force you exert in size, direction or both. -Simple machines try to move something that resists being moved. (Ex: friction or gravity)

There are 6 types of simple machines There are 6 types of simple machines. All are variations of lever or inclined plane. Lever Inclined plane 1. Lever 4. Inclined plane 2. Pulley 5. Screw 3. Wheel and 6. Wedge axle

Lever- a bar that is free to pivot or turn about a fixed point. - Fulcrum- fixed point of a lever Effort arm- part of the lever where the effort force is applied Resistance arm- part of the lever where there is resistance

There are different types of levers. -1st class Effort ▲ Resist Ex: seesaw scissors pliers

-2nd class Effort Resist ▲ Ex: Stapler Wheelbarrow Nail clippers

-3rd class Resist Effort ▲ Ex: Tweezers Swinging a bat Fishing rod

2. Pulley- a grooved wheel with rope running along the groove. There are 3 types of pulleys Fixed- the pulley is stationary Movable- the pulley can move Block and tackle- Fixed and movable put together

-Fixed -Movable -Block & Pulley Pulley Tackle Pulley

3. Wheel and axle- 2 wheels of different sizes that rotate together. Always travel in a circle. Effort force is applied to the larger wheel while the smaller wheel (axle) exerts the resistance force.

Example of a wheel and axle

4. Inclined plane- a sloping surface used to raise objects. Ex: a ramp. Using a ramp, you cover more distance but exerts less force.

Screw- an inclined plane wrapped in a spiral.

6. Wedge- an inclined plane with 1 or 2 sloping sides. -Wedges are moving inclined planes. Ex: Knife or ax blade.