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Results from the imbalance of charges on or in an object Discharges in the form of Shock Spark Lightning bolt Charges in continuous motion in a circuit

Before 500 BC, Thales noted that a piece of amber rubbed on silk attracted straw. He called the force of attraction between the amber and the straw electricity: since it was a force from an electron (the Greek for amber). Thus Thales discovered electrification by friction. 4

In the 1600 Gilbert discovered that many other objects can be electrified by friction. The understanding of electrification led to the classification of materials into insulators (capable of accumulating charges) and conductors (capable of transmitting charges). Electrical Shows. 5

DuFay later discovered that all materials can be charged by friction (conductor must be insulated). Early 1700s, He inferred the existence of two different types of electricity and bodies repel each other if they are charged by the same type.

Later in the same year, Pietra Musschenbroek developed the leyden jar: a device capable of storing electricity.

Franklin clearly explained the observations and results of the many experiments conducted in electricity and demonstrated that lightning is an electrical discharge.

In 1785, Coulomb established his law relating the electrical force and the distance between two charged objects.

Electrical charges and Matter 14

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Three main types of electrification By friction By contact By induction

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End of Chapter