1. There are six basic types of simple machines: wheel & axle, pulley, lever, inclined plane, wedge and screw. All simple machines either alter the directions of forces applied to them or multiply their effects.
2. Complex machines are made up of a combination of these simple machines.
3. Examples of simple machines are wheels, screw drivers, scissors, knives, nut crackers, and hammers.
4. A wheel and an axle together make a simple machine. Wheels and axles are used to carry loads around easily, for long distances with very less effort.
5. A pulley consists of a wheel with a groove around it. A rope can be passed through the groove. A pulley makes our work easy by changing the direction of the force applied. Instead of pulling the load up you are now pulling the rope downwards. It is always easy to pull down than to pull up.
6. Levers can help lift a heavy weight with much less effort. A lever consists of a rod, which balances on a fixed point. The heavy object that has to be moved or lifted is called the “Load” - the point at which the rod is fixed is called the “Fulcrum”.
7. An inclined plane can be defined as a tool that helps move heavy objects from a high place to low place and low place to high place. Inclined planes also move things quickly.
8. A wedge is basically a moving inclined plane. It is a hunk of strong material thick at one end and thin at the other. Chisels, axes, knives and doorstops are all wedges
9. A screw is a pointed nail with grooves in it. This thread of grooves is actually an inclined plane.
10. Archimedes of Syracuse was an ancient Greek scientist and inventor. Though he did not invent the simple machines, he did much of the early research and development of them.