1. History of Electricity

3. Thales of Miletus Greek philosopher, mathematician, and scientist
600 B.C. - amber becomes charged by rubbing
The Greek word for amber is elektron.
Amber attracted objects when rubbed
Believed amber contained a psyche (soul)

4. Jerome Cardan ( )
amber attracts lightweight objects (such as straw, cotton fibers, etc.)
he mineral magnetite attracts only iron.

5. William Gilbert (1540-1603) Queen Elizabeth I's doctor
named electricity for the Greek word elektron for amber
if two non-metal rods were rubbed briskly, they behaved similarly to amber
called those materials electrics (materials that we call insulators today)
Believed some type of fluid was responsible for this action (FLUID MODEL)

6. Fluid model of electricity
one-fluid model of electricity
a physical transfer of the single fluid occurred when an object became electrically charged, leaving one surface with 'negative' charge and one with 'positive' charge

7. Otto von Guericke ( )
von Guericke invented a another machine for producing static electricity.
It consisted of a ball of sulfur that was hand-rotated by a crank.
A piece of wood held against this sphere would produce a large spark.
Eventually evolved into:
Van de Graaf generator

8. Charles DuFay (1730's)
charged pieces of glass repelled other glass-like materials, but attracted substances similar to amber.
two kinds of electricity must exist. He called these vitreous ("glassy") and resinous (amber-like).
DuFay had discovered negative and positive electric charge, although he thought they were actually two types of electric "fluid." (TWO FLUID MODEL)

9. two-fluid model of electricity
Two fluids exist
like fluids repelled, unlike attracted

10. Pieter van Musschenbroek
invented the Leyden Jar, which stores electric charge

11. Benjamin Franklin ( )
The theory in Franklin's time was that electricity was some kind of fluid
objects had too much fluid, they would repel each other
but they would attract objects with too little fluid
object with an excess of fluid touched an object with too little fluid, then the fluid would be shared.

12. Benjamin Franklin ( )
Franklin used the term positive for what he thought was an excess of electric fluid
negative for a deficiency of fluid.

13. Models change over Time
Science is an ever changing discipline
With each new bit of information new models have to be introduced to explain the new phenomenon