The Nature of Electricity
Year of Discovery: 1752
What Is It? All forms of electricity are the same.
Who Discovered It? Benjamin Franklin
Why Is This One of the 100 Greatest?
Electricity is one of our greatest energy resources and one of the few natural energy
sources. Franklin’s electricity experiments were the first scientific ventures into the nature
and use of electricity and uncovered its true nature. They set the stage for much of the scientific and engineering development in the nineteenth century and for the explosion of electrical development—batteries, motors, generators, lights, etc.
How Was It Discovered?
All that was known about electricity in the mid-eighteenth century was that there were
two kinds of it: playful static and deadly lightning. Benjamin Franklin was the first scientist
to begin serious electrical experiments (in 1746). He was also the first to suspect that static
and lightning were two forms of the same thing.
Franklin had been experimenting with Leyden jars—large glass jars, partially filled
with water and wrapped with tin foil both inside and out. A rod extended through an insulating cork out the top of the jar to a metal knob. Once a Leyden jar was charged with a hand
crank, anyone who grabbed the knob got a resounding shock.
Franklin found ways to more than double the amount of electricity his Leyden jars carried, and he invented a way to connect them in series so that they could, collectively, carry
an almost deadly punch.
During a 1752 demonstration for friends, Franklin accidentally touched a Leyden jar’s
knob. With a sharp crack, a sizzling blue arc leapt from jar to Franklin’s hand. He shot back
half a dozen feet and crashed to the floor. Franklin realized that that jolt looked exactly like
a mini-lightning bolt.
He decided to prove that static and lightning were the same by designing a Leyden
jar–like electric circuit to let electricity flow from clouds just as it did into a jar.
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