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

Mystery of the Physical World The Mystery of the Physical World The earliest humans surely encountered lightning. They must have wondered about it! What is it? What creates it? Have you ever been caught exposed outdoors during an intense thunderstorm? That’s a frightening experience. Is it any wonder that the early humans ascribed lightning to supernatural forces? But today we understand lightning as an effect of electricity. Mystery of the Physical World Week 1

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. Week 1

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. Week 1

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. /b/ Benjamin Franklin The concept of positive and negative charge was first explained by Benjamin Franklin. {READ} Week 1

Coulomb’s torsion balance Charles Augustin de Coulomb (1736 – 1806) The apparatus used by Coulomb to measure the electrostatic force. His clever idea was to use a fine torsion balance to measure this weak force very accurately. {READ} Week 1

The discovery of the electron (J J Thomson, 1897) Thomson: The cathode ray is a beam of identical particles –- electrons. /d/ J. J. Thomson {READ} The full understanding of electric charge did not exist until 1897, when J J Thomson discovered the electron. He showed that a cathode ray consists of a beam of absolutely identical particles. He named the particle “electron.” Today we control electrons. That is the technology of electronics. Week 1