The spiral is a shape that has fascinated humans since ancient times. The first symbols drawn on the planet were spirals, thought to represent the sun and eternity.
When one thinks of spirals in nature, univalve seashells immediately come to mind. These spirals are logarithmic, the distance between the turns increasing as the shape becomes larger. (Don’t confuse this shape with an archimedean spiral).
Logarithmic spirals were called spira mirabilis ( marvelous spirals) by the scientists who first studied them. Besides seashells, this shape is also found in fiddlehead ferns in spring time, the arrangement of seeds in sunflowers and the scales of pinecones. Not all spirals in nature are static. Galaxies and tornadoes follow this shape, as do hawks in their approach to prey in flight.
The spiral is one of several interesting shapes that are found repeatedly in nature. These shapes often form exquisite patterns and many are building blocks for larger things. Last week I wrote about the meander.
In the Saturdays between now and mid-summer’s eve, I’ll explore a number of other shapes found in nature as a lead-up to a Summer Scavenger Hunt. Details of the hunt to be disclosed June 20th.
For more information on the spiral form in freshwater and sea shells, see the shell section at Drawing Conclusions.