The Fraction Wheel Pulley Machine
This interactive application uses pulleys to create an animated fraction wheel. Students connect different size pulleys and turn a crank to produce multicolored fraction wheel sections. The possible fractions include all fractions with denominators less than or equal to 12. For each fraction the fraction wheel displays all the fractions in the family of the fraction, e.g. for 1/12, the fractions with denominator 2, 3, 4, or 6.
The value of this application is that it gives students both a visual and a mechanical model of fractions and relates the concept of fraction to the important concept of ratio. In this regard the web page includes notes that explain how the mechanism used to operate the fraction wheel is essentially the same as that used in bicycle gears. Though the page can be run without an internet connection it includes links to two YouTube videos that demonstrate the use of bicycle gears and how they work. Thus this application makes an excellent introduction to a laboratory in which students experiment and observe for themselves how the concept of ratio applies in practice. This also can also be used in a science unit on simple machines.