Title: Gears: the Long and Short Versions
Course: Open PRO125-Process Tech 1-Equipment 2 > Section: Module 7: Mechanical Power Transmission and Lubrication

This first video is a great 10 minutes segment for the basics. The second one is excellent and at nearly 40 minutes it's very in-depth but you may find it worth your while.

http://youtu.be/odpsm3ybPsAThis video resource is designed to provide a basic introduction to gears suitable for grades 4 to 9. Gear rotation, gear ratio, rates of rotation, mechanical advantage and examples of use are included. A second video, " Time, Clocks and Gears" explains how gears are used in mechanical clocks to control the hands on an analog clock.

http://youtu.be/9VUdF3iC42I