Circumference & Diameter - Chain On Cylinder
To show the relationship between the diameter and the circumference of a circle.
Aluminum cylinder and chain on stand, assembled as photographed on request.
A chain, originally wound around a cylinder, is unwound. The diameter of the cylinder can be compared with the length of the chain wound off one turn,so the value of pi may be approximated.
The AAPT Metric Education and SI Practices Committee (Gordon J. Aubrecht, II, Anthony P. French, Mario Iona, and Daniel W. Welch), The Radian - That Troublesome Unit, TPT 31, 84-87 (1993).Robert J. Whitaker, Whence the "Radian"?, TPT 32, 444-445 (1994).