There are six types of simple machines • Lever • Pulley • Screw • Wheel and Axle • Inclined plane • Wedge
Lever • A lever is a rigid object that pivots or rotates on a fixed point. • The fixed point is called a fulcrum.
First Class Levers • In first class levers the input (the force you put in) is on the opposite end of the output (the work the lever does). • Examples of this are see saws, scissors and pliers
Second Class Levers • Second class levers have the fulcrum on one end with the input (the force you put in) on the other end and the output (the work the machine does) in the middle. • Some examples are wheel barrows, nut crackers and doors.
Third Class Levers • Third class levers have the fulcrum on one end and the output (the work the machine does) on the other end with the input (the force you put in) in the middle. • Examples of third class levers are baseball bats, hockey sticks, shovels and your arm.
Pulleys • Pulleys are made up of a grooved wheel and some sort of rope or cable. • Examples of a pulley are the pulley at the top of a flagpole, a construction crane and the pulleys that make weight machines work.
Three Types of Pulleys Block and Tackle
Screw • A screw is an inclined plane wrapped around a cylinder. • Try this… take out a piece of paper and fold it so it makes a large triangle. Start at the top of your writing utensil and wrap the triangle around it. Notice what you get.
Wheel and Axle • A wheel and axle is a simple machine made from two circular objects fastened (attached) together that rotate.
Inclined Plane • An inclined plane is a simple machine made of a sloped surface. A ramp and stairs are examples of inclined planes.
Wedge • A wedge is actually 2 inclined planes put back to back. A wedge moves and a regular inclined plane does not. Examples of wedges are axes, your teeth, knives etc.