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Simple machines

Simple machines make work easier by changing either the amount of force needed, the direction of force, or reducing friction. The six simple machines are the inclined plane, wedge, screw, lever, wheel and axle, and pulley. An inclined plane is a flat, slanted surface that allows a force to be exerted over a longer distance, making work easier. A wedge is thick on one end and tapers to a thin edge, and is used for cutting or prying by changing the direction of applied force. A screw is essentially an inclined plane wrapped around a cylinder and changes the direction of applied force as it moves up or down.

Education◦
Simple Machines
What is a Machine?  A device that allows you to do work in a way that is easier or more effective.  A machine can do at least one of these 3 things: 1. Change the amount of force 2. Change the direction of the force 3. Cut down the amount of friction
Pulley Wheel & Axle Lever Screw Wedge Inclined Plane Simple Machines
The Inclined Plane  An inclined plane is a flat, slanted surface  It allows you to exert your force over a longer distance
Inclined Plane  Inclined planes make it easier to get things up higher or down lower  You can roll or slide things on a ramp
Types of Inclined Planes Ramps Stairs Roads The steeper the slant…the more work it takes to go up the inclined plane
Inclined Plane
The Wedge  A wedge is a device that is thick at one end and tapers to a thin edge at the other end  In a wedge, instead of an object moving along the inclined plane, the inclined plane itself moves.
Wedge Uses  A wedge is used for cutting, splitting, or prying things apart.  Zippers use wedges to push 2 sides together.
Types of Wedges  Axe  Zipper  Chisel  Razor Blade  A wedge can change the direction of the force. When you use a wedge to pry, not as much force is needed.
The Wedge
The Screw  A screw can be thought of as an inclined plane wrapped around a cylinder.  A screw changes the direction of the force, meaning as you turn it, it goes up or down.
The Screw  A screw is really an inclined plane. The ridges around it are like a road up a mountain.  The ridges on a screw are called threads.
Types of Screws  Jar lid  Water faucet  Car jack  Bolts
The Screw
The Lever  A lever is a rigid bar that is free to pivot or rotate around a fixed point.  The fixed point that the lever pivots around is called the fulcrum.
3 Types of Levers  1st Class Lever - the pivot (fulcrum) is between the effort and the load. Item Number of Class 1 Levers Used see-saw a single class 1 lever hammer’ s claws a single class 1 lever scissors 2 class 1 levers pliers 2 class 1 levers
3 Types of Levers  2nd Class Lever - the load is between the pivot (fulcrum) and the effort. Item Number of Class 2 Levers Used bottle opener a single class 2 lever wheelbarrow a single class 2 lever nail clippers Two class 2 levers nut cracker Two class 2 levers
3 Types of Levers  3rd Class Lever - the effort is between the pivot (fulcrum) and the load. Item Number of Class 3 Levers Used fishing rod a single class 3 lever tweezers Two class 3 levers tongs Two class 3 levers
Examples of Levers  Seesaw  Crowbar  Chopsticks  A lever increases the effect of your input force and changes the direction of your input force.
The Lever
3 classes of levers
The 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.  Sometimes the wheel has a crank or handle on it.
The Wheel and Axle  The wheel and axle, moves objects across distances.  The wheel, the round end, turns the axle, the cylindrical post, causing movement.
Wheel & Axle
The Pulley  Instead of an axle, the wheel could also rotate a rope or cord.  This variation of the wheel and axle is the pulley.  In a pulley, a cord wraps around a wheel. As the wheel rotates, the cord moves in either direction.
Types of Pulley  Now, attach a hook to the cord, and you can use the wheel's rotation to raise and lower objects.  On a flagpole, for example, a rope is attached to a pulley. The cord rotates around the pulley and lowers the hooks where you can attach the flag. Then, rotate the cord and the flag raises high on the pole.  A crane uses a simple machine called a pulley to lift things. Our crane uses a pulley to move the metal beams from the ground to the air.
The Pulley
Mechanical Advantage  MA = Is determined differently for each type of simple machine  Force Measured in Newtons  Distance Measured in Meters Mechanical advantage is the number of times a force exerted on a machine is multiplied by the machine. If this # is greater than 1 the machine is extremely useful There are 2 types of Mechanical Advantage
Output Force Actual Mechanical Advantage = Input Force The actual mechanical advantage (AMA) is the mechanical advantage of a real machine. Actual mechanical advantage takes into consideration real world factors such as energy lost in friction The ideal mechanical advantage (IMA), or theoretical mechanical advantage, is the mechanical advantage of an ideal machine. It is usually calculated using physics principles because there is no ideal machine. Each individual Machine has it’s own formula for calculating Ideal Mechanical Advantage
Mechanical Advantage
Go home and find 3 “real life” examples of each simple machine.  3 Inclined Planes  3 Wedges  3 Screws  Levers 1 1st Class Lever 1 2nd Class Lever 1 3rd Class Lever  3 Wheels and Axels  3 Pulleys
References  http://www.cosi.org/onlineExhibits/simpMa ch/sm2.html  www.Unitedstreaming.com  Microsoft clipart