ANDY-D&T

Monday, April 28, 2008 ♠

For a toy to work, there must be a reason behind it.
Toys work under the theory of different simple machines working together.
The more complicated a toy is, the more number of simple machines will be used.

Simple machines are types of machines that do work with one movement.

There are a few main simple machines;

INCLINED PLANE
An inclined plane is a slanted surface used to raise an object. A ramp is an inclined plane. When an object is moved up an inclined plane, less effort is needed than if you were to lift it straight up, but, you must move the object over a greater distance.

SCREW
A screw, is another form of an inclined plane. A screw is an inclined plane wrapped around a cylinder to form a spiral.

LEVER
Levers are simple machines used to lift weights.
1st class lever
An example of this type is a seesaw. The load is the person that goes up, and the effort applied is the weight of the person that goes down. The fulcrum is in the center in between them.
2nd class lever
An example of a Second Class Lever is a can opener. The difference from the first class lever is that the fulcrum is on the end, instead of in the middle.
3rd class lever
An example the Third Class Lever is a fishing rod. The load is the fish; the handle end is the fulcrum.

PULLEY
A pulley is a chain, belt or rope wrapped around a wheel. The mechanical advantage of a pulley system is approximately equal to the amount of supporting ropes or strands.

WHEEL AND AXLE
A wheel and axle is a lever that rotates in a circle around a center point or fulcrum. The larger wheel (or outside) rotates around the smaller wheel (axle). Bicycle wheels, ferris wheels and gears are all examples of a wheel and axle. Wheels can also have a solid shaft with the center core as the axle such as a screwdriver or drill bit

Information from : http://library.thinkquest.org/J002079F/lever.htm
http://www.usoe.k12.ut.us/CURR/Science/sciber00/8th/machines/sciber/intro.htm

Posted @ 10:20 PM