All 6 simple machines:
1. Lever - a rigid bar, straight or curved, that is free to turn about a fixed point called the fulcrum. Ex. wheelbarrows, pliers, scissors, etc.
The lever has three parts:
- resistance force, or load - what is being moved or lifted
- effort force - the force that the lever exerts, or the work done on the lever
- fulcrum - the fixed pivot point
2. The Wheel and Axle - a machine where a large wheel is connected to a smaller whell or shaft called an axle. Ex. automobile steering wheels, doorknobs, gear wheels of the bicycle, screwdrivers, eggbeaters, meat grinders, pencil sharpeners, etc.
Facts:
- When either the wheel or the axle turns, the other part also turns.
- One complete turn of the wheel produces one complete turn of the axle.
- If the wheel turns but the axle doesn't, it is not a wheel-and-axle machine.
3. Pulley - A pulley is a wheel that turns around an axle. Usually, there is a groove in the rim of the pulley so that the rope around the pulley will not slip off. Ex. flagpole, etc.
- A pulley may be fixed, movable or a combination of both called block and tackle.
- The pulley is a modified lever.
4. Inclined Plane - a surface that is raised at one end. Ex. plank, the sloping floor of a theater or auditorium, a zigzag road up a mountain, stairway, etc.
- It is a simple machine that gives us a gain in force. Less force is used in getting an object up to the higher end of an inclined plane than if the object is to be lifted directly from the lower level up to the raised end. The gain in force means a longer distance for the object to travel up an inclined plane.
- The longer the inclined plane, the more gradual the slope becomes, and less force will be needed to move the object up the incline.
- The shorter the inclined plane, the steeper the slope becomes, and more force will be needed to move the object up the incline.
5. Wedge - a form of inclined plane that tapers to a sharp edge.Ex. ax, knife blade, scissors blade, chisel, pin, nail, plow, etc.
- It can be a sloping surface (a single inclined plane) or two sloping surfaces (a double inclined plane).
- The wedge gives us a gain in force and also changes the direction of the force.
- The longer or thinner the wedge, the greater the gain in force.
6. Screw - an inclined plane wrapped in a spiral around a cylinder post.
A screw is composed of the body (the cylinder post) and the thread, which is the spiral ridge of the screw. The threads form a tiny ramp that runs around the screw from the tip to near the top. One complete turn of the screw moves it into the object a distance from one thread to another. The distance between two consecutive threads is called the pitch of the screw. The screw gives us a gain in force, but at the expense of distance.
Ex.
- nuts and bolts used to fasten things
- drill bits used to make holes
- jackscrews used to lift heavy objects
- airplane propellers, helicopter blades and blades that screw through the air
- propellers on boats that screw through the water
- caps of jars
- base of the electric light bulb
- monkey wrench
- clamp
- vise
- and etc.
Whew...hope that helped! ^_^ ♥