Hooke’s law Hooke’s interests The balance spring Commentary

Robert Hooke horology

Hooke’s law

• Robert Hooke invented the balance spring for watches
• and formulated the physical principle on which it depends.
• This principle is also known as the law of elasticity.
• The force you apply to compress or extend a spring
• is proportional to the distance you move it.

Hooke’s interests

• Robert Hooke was Surveyor to the City of London,
• and chief assistant to Christopher Wren.
• He was Curator of Experiments for forty years
• for the Royal Society of London
• so was responsible for demonstrating
• and given opportunity for extending
• the ideas of other scientists.
• His interests and expertise ranged widely—
• astronomy, physics, optics, mechanics, horology,
• surveying, architecture, acoustics, geology,
• paleontology, microscopy, biology, and chemistry.
• Hooke created a theory of gravity and planetary motion,
• tried to measure the distance to a star using parallax,
• drew the rings of Saturn and craters on the moon,
• discovered one of the first observed double-star systems,
• wrote about earthquakes and the deformation of rock,
• understood that fossils derived from once-living plants and animals,
• helped design the dome of Saint Paul’s Cathedral,
• discovered nodal patterns of vibrations on glass plates,
• invented the anchor escapement and the balance spring,
• discovered that plants have cells,
• improved the vacuum pump,
• understood that combustion requires a component in air,
• and developed a complete and modern theory of memory.

The balance spring

• Christiaan Huygens reinvented the balance spring
• fifteen years after Hooke.
• Hooke had shelved his work on clocks after finding
• he couldn’t make enough money for it.
• Hooke suggested that Newton look at ellipses
• for the motions of the planets
• but probably didn’t realize, as Newton did,
• the mathematical simplicity of gravity.
• In this age, science was too much a hobby
• of wealthy men.
• Hooke was a working man who could not afford
• to give his ideas away.