(Freshwater, England, 1635 - London, 1703) English astronomer and physicist. Although it is mainly known for his studies on elasticity, were notable also his astronomical discoveries and contributions to biology.
Formed at the University of Oxford, Robert Hooke worked in the bosom of this institution with the British chemist Robert Boyle in the construction of a pump of air (1655). Five years later he formulated the law of elasticity which bears his name, that establishes the relationship of direct proportionality between stretching undergone by a solid body and the applied force to produce this stretch.
Hooke formulated this law as a result of their experiences, that placing weights in the bottom of metal springs and measuring up to where the docks stretching as reaction. He observed that the length in which the spring is stretched was always proportional to the weight which placed him; i.e. If for example doubling the weight, it also doubled the length. Study of elasticity of materials is based on this law.
Hooke applied his studies to the construction of watch components: developed the leak of Looper control of pendulum clocks (1666), and created the universal joint allowing to transmit the motion between two shafts angled among themselves, without having to mount helical gears in them. In 1662 was named head of experimentation of the Royal Society of London, being elected member of the society the following year.
In 1664, with a telescope of homebuilt Gregory, Robert Hooke discovered the fifth star of the trapezium, in the constellation of Orion; It was also the first to suggest that Jupiter rotates around its axis. His detailed descriptions of Mars were used in the 19th century to determine its rotation speed. A year later he was appointed Professor of geometry at Gresham College.
That same year published Robert Hooke Micrographia (1665) work, which described in detail the structures of different insects, fossils and plants on the basis of a series of microscopic observations. After examining the porous structure of Cork, Hooke coined the term "cell" to designate the tiny polyhedral cells he saw; already in the 19th century, modern cytology would adopt this term to designate the basic structural unit of the tissues.
Micrographia also included studies and illustrations of the Crystallographic structure of snowflakes and discussions on the possibility to manufacture artificial fibers through a process similar to that follow the silk worms. Hooke studies on microscopic fossils led him to be one of the first pioneers of the theory of the evolution of species.
In 1666 he suggested that gravity could be determined by the movement of a pendulum, and tried to demonstrate the elliptical path which describes the earth around the Sun; their ideas anticipated the law of universal gravitation Isaac Newton, but it did not develop them mathematically. In 1672 he discovered the phenomenon of light diffraction; to explain this phenomenon, Hooke was the first to attribute to light a wave-like behavior.