1. Inclined Planes
1.1. Examples
1.1.1. slides, ramps, staircase, mountain pass
1.2. Definition
1.2.1. An inclined plane is a flat surface with one end higher than the other. This allows for heavy objects to slide up to a higher point rather than be lifted. It is generally easier to slide something than to lift it.
1.3. Two Variations of Inclined Planes
1.3.1. Screws
1.3.1.1. Examples
1.3.1.1.1. swivel chairs, jar lids, screws
1.3.1.2. Definition
1.3.1.2.1. A screw is a special kind of inclined plane. It's basically an inclined plane wrapped around a pole. Screws can be used to lift things or to hold them together.
1.3.2. Wedges
1.3.2.1. Definition
1.3.2.1.1. If you put two inclined planes back to back, you get a wedge. A wedge is a simple machine used to push two objects apart.
1.3.2.2. Examples
1.3.2.2.1. knives, chisels, axes
2. Wheels and Axels
2.1. Definition
2.1.1. It uses a wheel with a rod attached in the middle as an axle to help it to lift or move loads.
2.2. Examples
2.2.1. bicycle, fishing reel, doorknob, rolling pin
3. Pulleys
3.1. Examples
3.1.1. cranes, flag poles, window blinds
3.2. Definition
3.2.1. It uses a wheel with a groove in it and a rope. The rope fits into the groove and one end of the rope goes around the load. You pull on the other end. The pulley helps you to move the load or change direction of the force.
4. Levers
4.1. Examples
4.1.1. seesaw, pliers, crowbars, tweezers
4.2. Definition
4.2.1. The lever is made up of a straight rigid object like a board or a bar which pivots on a turning point called a fulcrum.