Great Scientists and their Inventions
Robert Hooke: (Lived 1635 – 1703)
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Robert Hooke was a Renaissance Man – a jack of all trades, and a master of many.
He wrote one of the most significant scientific books ever written, Micrographia, and made contributions to human knowledge spanning Architecture, Astronomy, Biology, Chemistry, Physics, Surveying & Map Making, and the design and construction of scientific instruments.
The Measurement of Time
In about 1657, Hooke greatly improved the pendulum clock by inventing the anchor escapement. This was a cog which gave a small push to every swing a pendulum took, preventing it running down, while also moving the hands of the clock forward.
In about 1660, Hooke invented the balance spring, vital for accurate timekeeping in pocket watches, one of which he made for his own use. A pendulum cannot be used in a pocket watch, so another way of marking the passage of time is needed.
Hooke’s balance spring was attached to a balance wheel and produced a regular oscillation; this oscillation allowed time to be kept accurately. Christiaan Huygens invented the balance spring independently of Hooke over a decade later.
In 1660 Hooke discovered Hooke’s Law, which states that the tension force in a spring increases in direct proportion to the length it is stretched to.
Micrographia and Microscopy
In 1665, when he was aged 30, Hooke published the first ever scientific bestseller: Micrographia.
The book was a showcase for Hooke’s particular talents – his understanding of nature and light, his highly developed skills in designing and constructing scientific instruments, and his skills as an artist.
Hooke had built a compound microscope with a new, screw-operated focusing mechanism he had designed. Previously, people needed to move the specimen to get it in focus.
He further improved the microscope with lighting. He placed a water-lens beside the microscope to focus light from an oil-lamp on to his specimens to illuminate them brightly.
Hooke used his microscope to observe the smallest, previously hidden details of the natural world. His book Micrographia revealed and described his discoveries.
Some people disputed his diagrams because they refused to believe what they showed. The world Hooke had discovered was too alien for them!
The Importance of Hooke’s Micrographia
Micrographia was one of the most important scientific books ever written, because it revealed a new world that people had never imagined could exist. Our knowledge of microbiology, quantum physics and nanotechnology can all be traced back to Hooke’s Micrographia and the path some scientists were inspired to follow after seeing the world Hooke had revealed.
Hooke’s Discovery of Microscopic Fungi
Hooke discovered the first known microorganisms, in the form of microscopic fungi, in 1665. This preceded Antonie van Leeuwenhoek’s discovery of single-celled life by nine years.
Hooke’s Discovery of Plant Cells
Hooke looked at the bark of a cork tree and observed its microscopic structure. In doing so, he discovered and named the cell – the building block of life. He thought the objects he had discovered looked like the individual rooms in a monastery, which were known as cells. Hooke did not discover the true biological function of cells.
Micrographia and Paleontology
Hooke used his microscope to study the ancient cells in fossilized wood. He concluded that fossils had once been living creatures whose cells had become mineralized. He also concluded that some species that had once existed must have become extinct. Although this is now accepted by almost everyone his proposal was controversial when he made it.
The Force of Gravity
In a lecture in 1670, Hooke correctly said that gravity applied to all celestial bodies and that the force of gravity between bodies decreases with the distance between them. If the force were to be removed, the celestial bodies would move in straight lines.
Hooke the Architect
While working as a scientist, Hooke developed a sideline career as an architect. People liked his designs for buildings, and he was appointed to be Surveyor to the City of London. In fact, he made much more money as an architect than as a scientist, because he designed many of the buildings which replaced those destroyed by the Great Fire of London in 1666.
Robert Hooke died aged 67, on March 3, 1703, in London. He had suffered ill-health for some years, but the precise cause of his death was not recorded. Thanks mainly to his work as an architect, he died a very wealthy man.
The last words come from Hooke himself, from Micrographia.
By the help of microscopes, there is nothing so small, as to escape our inquiry; hence there is new visible world discovered to the understanding.