Six Simple Machines have many uses. 

 

      There are six simple machines:

 

1.  Lever

2.  Wheel and Axle

3.  Pulley

4.  Inclined Plane

5.  Wedge

6.  Screw

 

       Simple Machines- Six machines from which all other machines are based.

 

LEVER

 

      A solid bar that rotates, or turns, around a fixed point.

      That fixed point is called a fulcrum. 

      Multiplies the input force.

      Can change direction of the  input force.  

      If you apply a force downward on one end of the lever, the other end can lift a load. 

 

 There are three classes of levers.

1. First-Class Lever- The fulcrum is between the input and output forces.

 EXAMPLE: CROWBAR

 

2. Second-Class Lever- The output force is in between the input force and the fulcrum.

 EXAMPLE: WHEELBARROW

 

3. Third-Class Lever- The input force is located between the output force and the fulcrum.

 EXAMPLE: TWEEZERS

 

 WHEEL AND AXLE

      Made of a wheel attached to a shaft, or axle.

      Wheels of bikes and cars are attached to axles.

      The axle acts like a fulcrum.

      EXAMPLES: SCREWDRIVERS,STEERING WHEELS, DOORKNOBS 

      You apply a force to turn the axle or wheel.

      Your input force is transferred.

      Since the axle is smaller, the output force acts over a shorter distance than the input force.

 

PULLEY

      A wheel with a grooved rim and a rope or cable that rides in the groove.  

      As you pull the rope, the wheel turns.                                               

      A fixed pulley is attached to something that holds it steady.  

            -Changes the direction of the force.

            -Does not reduce the force needed to lift the load.

            -distance pulled = distance lifted

      A movable pulley setup is when the rope is fixed at one end but the wheel can move.

      A block and tackle system is a combination of both.  Used on very heavy objects.

 

INCLINED PLANE

      A simple machine that is a sloping surface.

      The less steep the inclined plane, the less force you need to push an object on an inclined plane. 

      This is because the steeper the plane, the less the plane supports the weight of the object.

 

WEDGE

      Simple machine with a thick end and a thin end.

      Used to cut, split, or pierce objects, or to hold objects together.

      EXAMPLES: DOORSTOPS, CHISELS, ICE SCRAPERS, AXE BLADES

      A chisel breaks things apart,while a doorstop holds things

       together

 

SCREW

      An inclined plane wrapped around a cylinder or cone to form a spiral. 

      Can be used to raise and lower weights as well as to fasten objects. 

      As the screw is turned, the threads act like wedges, exerting an output force on the wood.

 

SUMMARY

 

      SIX SIMPLE MACHINES HAVE MANY USES

      SIX SIMPLE MACHINES ARE: LEVER, WHEEL AND AXLE, PULLEY, INCLINED PLANE, WEDGE, SCREW

      THREE CLASSES OF LEVERS (1ST, 2ND, 3RD CLASS)

 

CHECK OUT:

 http://www.cosi.org/files/Flash/simpMach/sm1.swf

 FOR ANIMATIONS OF THE 6 SIMPLE MACHINES!