1-5.
BENJAMIN FRANKLIN (1750)
In 1750, Benjamin Franklin conducted tests on atmospheric electricity and friction
and concluded that the two phenomena were identical. As a result, he renamed Du
Fay's vitreous charge, a positive charge and resinous charge, a negative charge. (Ben
Franklin mistakenly concluded that positive charges move through a wire towards the
negative.)
1-6.
ALESSANDRO VOLTA (1775)
In 1775, Alessandro Volta invented an electrophorus electrostatic device, a
machine that produced light with static electricity. In 1800, he invented the Voltaic Pile,
the first device to produce continuous electric current, and the forerunner to the modern
wet-cell battery.
1-7.
MICHAEL FARADAY (1831-1833)
Between 1831 and 1833, Michael Faraday developed the Field Concept to
explain electromagnetic induction. He also formulated two basic laws of electrolysis. In
1838, Faraday studied the passage of electricity through gases. In the apparatus that he
used, he called one component the anode and the other the cathode.
1-8.
SIR WILLIAM CROOKES (1877)
a. Cathode Produces Fluorescence. In 1877, Sir William Crookes developed
the Crookes' partial vacuum tube. In 1879, he used the term cathode ray to describe
electrons emitted from the cathode in an evacuated tube. He characterized these rays
as negatively charged particles. (It should be noted that cathode rays are not x-rays.)
Crookes demonstrated that cathode rays produced fluorescence in various salts and
could be deflected (bent) by a magnet. Crookes also showed that a magnet could
deflect the narrow beam visualized by the bombardment of florescent screens.
b. Electrons Accelerated From Cathode. In the Crookes' tube, (figure 1-1),
cathode rays (electrons) were accelerated from the cathode to the anode by high
voltage. Many electrons traveled directly to the opposite end of the tube and there,
x-rays and fluorescent light were produced.
MD0064
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