Electrostatics

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Week 1 Electrostatics
A brief history of the science of electric forces

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Mystery of the Physical World
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Thales of Miletus (624 546 BC)
..considered the first philosopher in the history
of Western Civilization.
Thales observed that when amber is rubbed with
animal fur, it exerts weak forces, e.g.,
attracts small bits of straw or feathers.
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William Gilbert (1544 1603)
Scientist and physician (Queen Elizabeth was one
of his patients) Gilbert showed that many other
material besides amber acquire the ability to
exert forces when rubbed with another
material. He coined the word electricity from
the greek word for amber (hlektron) for this
phenomenon.
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Benjamin Franklin (1706 1790)
Franklin began as an amateur in electricity, but
became a famous scientist. His important
theoretical idea the one-fluid model that
electricity is carried by a single fluid and an
object can be positive (excess of fluid) or
negative (deficit of fluid). ? Conservation of
charge His famous kite experiment showed that
lightning is an electric discharge.
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Coulombs torsion balance
Charles Augustin de Coulomb (1736 1806)
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The discovery of the electron (J J Thomson, 1897)
Thomson The cathode ray is a beam of identical
particles - electrons.