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.Lever 2.Inclined Plane 3.Wheel and Axle 4.Screw 5.Wedge 6.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. CompoundPulley
THE PULLEYExamples of Pulleys in every day life: