Robert Hooke

Formed at the University of Oxford, Robert Hooke collaborated in the heart of this institution with the British chemist Robert Boyle in the construction of an air pump (1655). Five years later he formulated the law of elasticity that bears his name (Hooke’s law), which establishes the direct proportional relationship between the stretch suffered by a solid body and the force applied to produce that stretch.

Hooke formulated this law as a result of his experiences, in which he placed weights on the bottom of metal springs and measured how far the springs were stretched in reaction. He observed that the length in which the spring was stretched was always proportional to the weight placed on it; that is, if for example the weight was doubled, the length was also doubled. The study of the elasticity of materials is based on this law.

Hooke applied his studies to the construction of watch components: he developed the escapement of anchor for the control of pendulum clocks (1666), and created the universal joint that allowed to transmit the movement between two axes inclined to each other, without the need to mount them in gear wheels. In 1662 he was made responsible for the experimentation of the Royal Society of London, being elected a member of that society the following year.

In 1664, with a Gregory telescope of its own construction, Robert Hooke discovered the fifth star of the Trapeze, in the constellation of Orion; He was also the first to suggest that Jupiter revolves around its axis. His detailed descriptions of the planet Mars were used in the nineteenth century to determine it´s rotation speed. A year later he was appointed professor of geometry at Gresham College.

That same year Robert Hooke published his work Micrographia (1665), in which he described in detail the structures of various insects, fossils and plants based on a series of microscopic observations. After examining the porous structure of the cork, Hooke coined the term “cells” to designate the tiny polyhedral cells he saw; as early as the nineteenth century, modern cytology, a branch of biology centered on the study of the cell, would adopt this term to designate the basic structural unit of tissues.

The Micrographia also included studies and illustrations on the crystallographic structure of snowflakes and discussions about the possibility of manufacturing artificial fibers through a process similar to that followed by silkworms. Hooke’s studies on microscopic fossils led him to be one of the first precursors of the theory of the evolution of species.

In 1666 he suggested that the force of gravity could be determined by the movement of a pendulum, and tried to demonstrate the elliptical trajectory that the Earth describes around the Sun. His ideas anticipated the law of universal gravitation, but Hooke did not develop them mathematically; It was the founder of classical physics, Isaac Newton, who derived the law of gravity from its three fundamental principles on motion or Newton’s laws. In 1672 he discovered the phenomenon of luminous diffraction; To explain this phenomenon, Hooke was the first to attribute a wave behavior to light.

Source: Biografías y Vidas