Appearance in Nature

Abstract

Many spirals and vortices appear in nature both in the inanimate and the living world. As examples of the non-living nature some spirals and vortices of various sizes are selected: spiral galaxies, hurricanes and tornadoes, aerodynamic turbulence, crystal growth on surfaces and carbon nanotubes. In the realm of living structures, we consider rigid spiral forms (for example, seashells and snails), as well as flexible ones like the tail of a chameleon or a sea horse. Beyond fauna we find in flora many flowers and leaves that are arranged in spiral form. A general spiral tendency in vegetation is discussed, following ideas proposed by J.W. Goethe. The Fibonacci numbers, which are closely related to the positioning of leaves, are introduced. Other interesting topics are Leonardo’s flying spiral, insect eyes and fish vortices.