History of Electricity - Lecture Notes | TECH 208, Study notes of Biotechnology

Download History of Electricity - Lecture Notes | TECH 208 and more Study notes Biotechnology in PDF only on Docsity! History of Electricity  People are curious.  We want to know what forces act behind natural phenomena o Lightning, Hurricanes, Rain, etc  From observing these people developed theory for magnetism, electricity and electronics. o Magnetism: compass, navigation, world exploration. o Electricity: communications, medicine, electrical home devices, etc, heating, cooling. o Electronics: Stereo, computers, etc. A. Thales of Miletus (640 – 546 BC) o Observed that rubbing amber (yellowish translucent fossil) attracts straw and dust. o Greek: amber = elektron o Did NOT attract metal. o However, lodestone (magnetite) attracted little pieces of iron without rubbing! B. William Gilbert (1540 – 1603) a. Kept studying magnetism (after people were already using the compass for navigation. Chinese 1300). b. Decided that it was NOT the heat given off by rubbing that made amber attract objects, but the friction itself. C. Benjamin Franklin (mid 1700s) a. Concluded that electricity was NOT created, but transferred. b. There were two kinds of “electricity”: positive and negative c. There was an “electrical fluid.” d. Fluid went from one body to another. e. 1752: Famous kite experiment. f. Tied a stiff wire to the tip of the kite when storm was about to break. g. At the other end of the string he tied a metallic key. h. Moistened string conducted electricity! D. Alessandro Volta (1745-1827) a. Voltaic pile b. Stack of zinc and copper disks. c. Leather disks soaked in salt solution of mild acid (vinegar or lemon juice) d. Created voltage! E. Oersted (1820) a. Demonstrated the relationship between magnetism and electricity. b. Brought a compass near a current-conducing wire. c. The compass needle was deflected.