Simple Machines Simple Machines Simple machines are simple

Simple Machines

Simple Machines Simple machines are "simple" because most have only one moving part. n Machines do not reduce the amount of work for us, but they can make it easier. n When simple machines are put together they create complex machines n Machines have a mechanical advantage, the amount of output should be greater than the amount of input effort. n

Six types of Simple Machines Inclined Plane n Lever n Wheel & Axle n Pulley n Screw n Wedge n

Lever n n n LEVER: A stiff bar that rests on a support called a fulcrum. How it works: Lifts or moves loads. Examples: There are three types of levers. ¨ A first class lever is like a teeter-totter or see-saw. One end will lift an object up just as far as the other end is pushed down. ¨ A second class lever, the load arm lies between the fulcrum and the force arm. A good example of this type of lever is the wheelbarrow. ¨ A third class lever has the effort between the load and the fulcrum. Both the effort and load are in the same direction. Note that the length of the load arm goes all the way to the fulcrum and is always greater than the length of the effort arm. Tweezers are an example.

Parts of a Lever A typical lever consists of a solid board or rod that can pivot about a point or fulcrum. A force or effort is applied, resulting in moving or applying force to a load. The distance from the applied force or effort force to the fulcrum is called the effort arm and the distance from the load to the fulcrum is called the load arm.

Classes of Levers Class 1 Class 2 Class 3

Inclined Plane n n INCLINED PLANE : An inclined plane is a straight slanted surface connecting a lower level to a higher level at an angle. How it works: The inclined plane is simply a flat surface raised at an angle, like a ramp. It is a way of lifting a load that would be too heavy to lift straight up. The angle (the steepness of the inclined plane) determines how much effort is needed to raise the weight. The steeper the ramp, the more effort is required. Example: Ramp, slide, stairs, escalator

Wheel & Axle n n WHEEL AND AXLE : A wheel and axle is a modification of a pulley. A wheel is fixed to a shaft. The wheel and shaft must move together to be a simple machine. How it works: Lifts and moves loads of material. Examples: bicycle, doorknobs, pencil sharpener.

Pulley n n PULLEY: A pulley is a simple machine made with a rope, belt, or chain wrapped around a grooved wheel. How it works: A pulley works two ways. It can change the direction of a force or it can change the amount of force. ¨ A fixed pulley changes the direction of the applied force. ( Ex. Raising the flag ) ¨ A movable pulley is attached to the object you are moving. ¨ Examples: Curtain rod, tow truck, flagpole, crane

Wedge n n n WEDGE: A wedge is a modification of two inclined plane that move. How it works: A wedge is made of two inclined planes put together. Instead of the resistance being moved up an inclined plane, the inclined plane moves the resistance. Examples: Axe blade, car tire wedge, chisel, nail

Screw n n n SCREW: A screw is a simple machine that is like an inclined plane. It is an inclined plane that wraps around a shaft. How it works: A screw works by turning it into an object or flat surface. Then the threads (incline plane) that are around the shaft crush through the object. Examples: Screw, nuts, bolts, jar lip, light bulb end

Summary Simple machines are "simple" because most have only one moving part. n Machines do not reduce the amount of work for us, but they can make it easier. n "Work" is only done when something is moved. n Work is the product of effort and distance. n

ORGANIZER SIMPLE MACHINES WHAT IT IS HOW IT WORKS EXAMPLES LEVER A stiff bar that rests on a support called a fulcrum. Lifts or moves loads 1 st- Teeter totter 2 nd- Wheel barrow 3 rd- Tweezers INCLINED PLANE A slanting surface connecting a lower level to a higher level. Things move up or down it Slide, stairs, ramp, escalator WHEEL AND AXLE A wheel with a rod, called an axel, through its center: both parts move together. Lifts or moves loads Doorknob, pencil sharpener, bike

ORGANIZER SIMPLE MACHINES WHAT IT IS HOW IT WORKS EXAMPLES PULLEY A grooved wheel with a rope or cable around it. Moves things up, down, or across Curtain rod, tow truck, flag pole, crane WEDGE A type of inclined plane with a sharp edge. The wedge moves, the inclined plane stays still. Pushes things apart Axe blade, nail, car tire wedge SCREW An inclined plane Raises weights, wrapped around a presses or fastens cylinder. objects Screws, nuts

Name/period: _______________ SIMPLE MACHINES LEVER INCLINED PLANE WHEEL AND AXLE WHAT IT IS HOW IT WORKS EXAMPLES

SIMPLE MACHINES PULLEY WEDGE SCREW WHAT IT IS HOW IT WORKS EXAMPLES