Some Shapes
 Echinus (detail) Jean Baptiste Lamarck. Tableau Encyclopédique et Méthodique des Trois Regnes de la Nature, Paris 1791-1798. Photograph by D Dunlop.

A particle described by its wavelength $\lambda$ and orbital radius $\, R$ may be classified by shape.

 Shape Definition a point $R = \lambda = 0$ a line segment $\lambda > R = 0$ a plane section $R > \lambda = 0$ a plate $R \gg \lambda > 0$ a rod $\lambda \gg R > 0$ a cylinder $\lambda \sim R > 0$
 Next step: displacement.
page revision: 131, last edited: 06 Mar 2016 19:47