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WHAT ARE SIMPLE MACHINES?

• A simple machine is a device that makes work easier. They often change the direction or magnitude of a force and offer mechanical advantage.

• Simple machines are seen as the building blocks of more complex machines.

• Simple machines allow an applied force to work against a load force.

HOW DID WE FIGURE ALL OF THIS OUT?

• The group of devices were defined by renaissance scientists and are widely used to this day! • Archimedes first theorized the simple machine, but mainly studied the lever, pulley and screw. These three are known as the “Archimedean” simple machines. What a guy!• Also, our old favorite Galileo Galilei was the first to discover that the machines did not create energy they just transformed it. He wrote about this in his publication: “Le Meccaniche” (on mechanics)

HOW MANY SIMPLE MACHINES ARE THERE?There are a total of 6 simple

machines:1.Lever2.Inclined Plane3.Wheel and Axle4.Screw 5.Wedge6.Pulley

THE LEVER

• The lever is made by constructing some type of beam (long straight piece of material) and attach it to a fulcrum.

• This design allows the input force to be magnified for a greater output force.

THE LEVER (CONTINUED)

• There are 3 classes of levers and they all depend on where the fulcrum is:

1. Class one- fulcrum is in the middle (see-saw or scissors)

2. Class two- Fulcrum is on opposite side of where the force is being applied (wheel barrow or nut cracker)

3. Class three- Force in middle, fulcrum on one side and resistance on the other (tweezers)

THE INCLINED PLANE

• An inclined plane is a flat surface (ramp) at an angle to the ground making lifting or lowering easier.

• Incline planes reduce force required to move objects by changing the ratio of the distance the objects travels vs. the height it was lifted/lowered.

THE WHEEL AND AXLE

• This is a wheel connected to an axle (straight bar) that rotate together. •A hinge or bearing typically supports the wheel. • This is a cousin of the lever, as the hinge acts as the fulcrum.

THE SCREW• The screw is a machine that changes

rotational (round) motion into linear (straight) motion.

• A screw is typically a cylinder with threads wrapped around it. The screw moves into another object with or without threads that match.

• Screws amplify force. The larger the distance between the threads on the screw, the more magnified the force.

THE WEDGE

• The wedge is a triangular shaped tool that is essentially a small, transportable inclined plane.

• The wedge is typically used to separate two objects, lift an object, or hold an object in place.

• Force is applied to the blunt end and then the force is translated into a perpendicular force to the plane.

• The longer the wedge the more the mechanical advantage (although it takes longer).

THE PULLEY

• A pulley is a type of wheel and axle that has a cable/belt/rope/chain running along it’s circumference in a designated groove.

• There are three main types of pulley systems:

1. Fixed Pulley 2. Moveable Pulley 3. Compound Pulley

THE PULLEY

Examples of Pulleys in every day life: