General Information about GearsGears is one of the oldest pieces of gear known to mankind. They date back to the south-pointing Chinese chariot in the 27th century BC, created by Ma Jun, a mechanical engineer. The first explanation of gears was that "the direction of rotation is reversed when one cogwheel drives another cogwheel" - Aristotle in the 4th century. Just as Greek engineers used gears in clocks and waterwheels. (2010 Ronson Gears) The first gears were made from wood, they were used in wind to decrease and increase rotational speed. Gear manufacturing and design developed rapidly during the 19th century. (2014 eFunda, Inc.) Gears are considered wheels with teeth, sometimes called a cog. When the gears fit together, they are able to make things turn. You must have at least two cogs to do any work with a gear. The equipment comes in many different sizes, which helps them do their job. The purpose of gears is to be able to move from one moving object to another. Gears are used for many reasons, such as to increase or increase rotational speed, to move rotational motion to a different axis, or to keep two axes moving at the same time. There are many different types of gears used for different things, for example spur gears, helical gears, worm gears, internal gears, etc. Spur gears are one of the most commonly used gears because they have been around the longest. Spur gears have teeth that extend vertically relative to the gear face. Helical gears are actually similar to spur gears, the difference between them is that the teeth are not perpendicular to the face of the gear and tend to run smoother due to the greater number of teeth it has. (Gears and stuff, 2006) Worm gears are u...... middle of paper ...... bicycles and heavy industrial machines all rely on common gears, and without different types of gears, we would not be able to live in today's modern society. We know how they helped us build a modern civilization; it will be exciting to see what they help us accomplish in the future. Works Cited http://www.gearsandstuff.com/types_of_gears.htm http://bowlesphysics.com/images/Robotics_-_Gears_and_Gear_Ratios.pdf http://science.howstuffworks.com/transport/engines-equipment/gear5.htm http ://www.ronsongears.com.au/a-brief-history-of-gears.php http://www.efunda.com/designstandards/gears /gears_history.cfm http://www.odec.ca/projects /2006/seef6s2/everyday.htm http://www.wikihow.com/Determine-Gear-Ratio http://www.federalgear.com/blog/ the importance-of-gears-in-products-and -everyday-process http://www.ehow.com/how-does_5002084_clock-gears-work.html