MACHINES

Machines are devices that help people to do tasks. We have to distinguish between simple and complex machines.

A simple machine is a device that helps make work easier; a device that makes it easier to move something. Some simple machines are a wheel, a pulley, a lever, a screw, and an inclined plane. Most machines consist of a number of elements, such as gears and ball bearings, that work together in a complex way. No matter how complex a machine, it is still based on the compounding of six types of simple machines. The six types of machines are the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw.

–A pulley is a simple machine that uses grooved wheels and a rope to raise, lower or move a load.

-A lever is a stiff bar that rests on a support called a fulcrum which lifts or moves loads.

 -A wedge is an object with at least one slanting side ending in a sharp edge, which cuts material apart.

–A wheel with a rod, called an axle, through its center lifts or moves loads.

-An inclined plane is a slanting surface connecting a lower level to a higher level.

-A screw is an inclined plane wrapped around a pole which holds things together or lifts materials.

A Complex Machine  is a system in which simple machines all work together, parts of a complex machine that have just one function are called subsystems and often contain a simple machine.

-Finally, do the following activities. You’ll find them very interesting!

http://www.edheads.org/activities/simple-machines/frame_loader.htm

http://www.mystery-productions.com/hyper/Hypermedia_2003/Muirhead/website/toys.swf