Robert Hooke

Robert Hooke

Robert Hooke lived during what some people call the scientific revolution. This

was the era of Galileo, Newton, Decartes and Halley just to name a few. During this

age, Physics as we know it was still in its infancy. At this time scientists were not as

specialized as today. They often worked in many different areas, making small but

important contributions to all of their specialities. Hooke was no exception. His interests

spanned biology, anatomy, chemistry, astronomy, architecture, navel technology,

paleontology and of course physics.

Hooke was born on the Isle of Wight, July 18, 1635 and he died in 1703 at the

age of 68 in London England. As a child he survived smallpox, but was scarred

physically and emotionally for life. When Hooke was thirteen years old, his father, John

Hooke, a clergyman hung himself. Young Robert had much emotional pain in his youth.

Receiving a 100 pound inheritance from his father, Robert Hooke became an orphan of

sorts, being sent off to London.

As a boy, Robert Hooke had shown considerable interest and skill in mechanical

things, and this, along with Hooke's intelligence, did not escape the notice of Richard

Busby. Busby had a reputation for "flogging sense into them," but there was no threat

here for Robert Hooke. Busby saw great genius in Hooke, and got involved to the

extent of taking the boy into his own home.

Hooke was then educated at the University of Oxford. He served as assistant to

the English physicist Robert Boyle and assisted him in the construction of the air pump.

In 1662 Hooke was appointed curator of experiments of the Royal Society and served

in this position until his death. He was elected a fellow of the Royal Society in 1663 and

was appointed Gresham Professor of Geometry at Oxford in 1665. After the Great Fire

of London in 1666, he was appointed surveyor of London, and he designed many

buildings, including Montague House and Bethlehem Hospital.

Hooke anticipated some of the most important discoveries and inventions of his

time but failed to carry many of them through to completion. He formulated the theory of

planetary motion as a problem in mechanics, and grasped, but did not develop

mathematically, the fundamental theory on which the English physicist Sir Isaac

Newton formulated the law of gravitation. Hooke's most important contributions include

the correct formulation of the theory of elasticity,(known as Hooke's law) which states

that an elastic body stretches in proportion to the force that acts upon it; and analysis of

the nature of combustion. He was the first to use the balance spring for the regulation

of watches, and devised improvements in pendulum clocks. Hooke was also a pioneer

in microscopic research and published his observations, which included the discovery

of plant cells.

One of the first men to build a Gregorian reflecting telescope, Hooke discovered

the fifth star in trapezium, an asterism in the constellation Orion, in 1664 and first

suggested that Jupiter rotates on it's axis. His detailed sketches of mars were used in

the 19th century to determine that planet's rate on rotation. In Micrographia (1665;

"small drawings") he included his studies and illustrations of the crystal structure of

snowflakes, discussed the possibility of manufacturing artificial fibers by a process

similar to the spinning of a silkworm, and first used the word cell to name the

microscopic honeycomb cavities in a cork. His studies of microscopic fossils led him to

become one of the first sponsors to the theory of evolution.

He suggested that the force of gravity could be measured by utilizing the motion

of a pendulum (1666) and attempted to show that the earth and the moon follow an

egg-shaped path around the sun. In 1672 he discovered the phenomenon of diffraction

(the bending of light rays around corners); to explain it, he offered the wave theory of

light. He started the inverse square law to describe planetary motions in 1678, a law

that Newton Later used in modified form. Hooke complained that he was not given

sufficient credit for the law and became involved in bitter controversy with Newton.

Hooke was the first man to state in general that all matter expands when heated and

that air is made up of particles separated from each other by relatively large spaces.

Hooke's major contribution to physics came from an apparatus he designed to

measure an object's weight, the spring scale. He was able to show that the amount of

force applied to a spring was directly proportional to its overall change in length. This is

the relationship known as Hooke's Law. It is ironic that he is best remembered for this

apparatus, which was designed to conduct a different experiment and was never

intended to be the focus of interest.

Hooke also tried to develop a law of gravity. While his efforts were restricted to

celestial bodies, it was an important precursor to Newton's universal law of gravitation.

Like Da Vinci, Hooke designed at least forty flying machines, though none were ever

built. Finally he added to our knowledge of astronomy. He is credited with the discovery

of Jupiter's Red Spot and measuring its period.

Bibliography

1) "Hooke, Robert," Microsoft® Encarta® 98 Encyclopedia. © 1993-1997 Microsoft

Corporation. All rights reserved.

2) http://earthspace.net/~kmiles/spec/hooks.html

3) A&E;, Biographies, "Newton", 1996

4) Hall R., "The Revolution in Science 1500 ~ 1750", 1983

5) Eves H., "An Introduction to the History of Mathematics", 1983

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