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!