facts about the invention
of the Lightning Rod by Benjamin Franklin in 1752.
|Benjamin Franklin was fascinated by
storms; he loved to study them. If he were alive today, we could probably add
"storm-chaser" to his long list of titles.
It was in Boston, Massachusetts, in 1746 that Franklin first stumbled upon
other scientists' electrical experiments. He quickly turned his home into a little
laboratory, using machines made out of items he found around the house. During one
experiment, Ben accidentally shocked himself. Franklin spent the summer of 1747 conducting
a series of groundbreaking experiments with electricity. He wrote down all of his results
and ideas for future experiments in letters to Peter Collinson, a fellow scientist and
friend in London who was interested in publishing his work. By July, Ben used the terms
positive and negative (plus and minus) to describe electricity, instead of the previously
used words "vitreous" and "resinous." Franklin described the concept
of an electrical battery in a letter to Collinson in the spring of 1749, but he wasn't
sure how it could be useful.
|Later the same year, he
explained what he believed were similarities between electricity and lightning, such as
the color of the light, its crooked direction, crackling noise, and other things. There
were other scientists who believed that lightning was electricity, but Franklin was
determined to find a method of proving it.
1750, in addition to wanting to prove that lightning was electricity, Franklin began to
think about protecting people, buildings, and other structures from lightning. This grew
into his idea for the lightning rod. Franklin described an iron rod about 8 or 10 feet
long that was sharpened to a point at the end. He wrote, "the electrical fire would,
I think, be drawn out of a cloud silently, before it could come near enough to
strike..." Two years later, Franklin decided to try his own lightning experiment.
Surprisingly, he never wrote letters about the legendary kite experiment; someone else
wrote the only account 15 years after it took place.
In June of 1752, Franklin was in Philadelphia, waiting for
the steeple on top of Christ Church to be completed for his experiment (the steeple would
act as the "lightning rod"). He grew impatient, and decided that a kite would be
able to get close to the storm clouds just as well. Ben needed to figure out what he would
use to attract an electrical charge; he decided on a metal key, and attached it to the
kite. Then he tied the kite string to an insulating silk ribbon for the knuckles of his
hand. Even though this was a very dangerous experiment, (you can see what our lightning
rod at the top of the page looks like after getting struck), some people believe that Ben
wasn't injured because he didn't conduct his test during the worst part of the storm. At
the first sign of the key receiving an electrical charge from the air, Franklin knew that
lightning was a form of electricity. His 21-year-old son William was the only witness to
Two years before the kite and key experiment, Ben had
observed that a sharp iron needle would conduct electricity away from a charged metal
sphere. He first theorized that lightning might be preventable by using an elevated iron
rod connected to earth to empty static from a cloud.
Franklin began to advocate lightning rods that had sharp
points. His English colleagues favored blunt-tipped lightning rods, reasoning that sharp
ones attracted lightning and increased the risk of strikes; they thought blunt rods were
less likely to be struck. King George III had his palace equipped with a blunt lightning
rod. When it came time to equip the colonies' buildings with lightning rods, the decision
became a political statement. The favored pointed lightning rod expressed support for
Franklin's theories of protecting public buildings and the rejection of theories supported
by the King. The English thought this was just another way for the flourishing colonies to
be disobedient to them.
Franklin's lightning rods could soon be found protecting many
buildings and homes. The lightning rod constructed on the dome of the State House in
Maryland was the largest "Franklin" lightning rod ever attached to a public or
private building in Ben's lifetime. It was built in accord with his recommendations and
has had only one recorded instance of lightning damage. The pointed lightning rod placed
on the State House and other buildings became a symbol of the ingenuity and independence
of a young, thriving nation, as well as the intellect and inventiveness of Benjamin
Benjamin Franklin Biography from The Great
Invention of Bifocal
from The Great Idea
from The Great Idea Finder
ON THE BOOKSHELF:
The Stories of Twenty American Kid Inventors
by Tom Tucker, Richard Loehle / Paperback - 144 pages / Sunburst (1998)
The stories of twenty ingenious young Americans who have filed patents with the
United States Patent Office, including Chester Greenwood who invented ear muffs, Ralph
Samuelson, originator of water-skiing, and Vanessa Hess who created colored car wax.
Crash, Rumble, and Roll
by Franklyn Mansfield Branley, True Kelley / Paperback - 32 pages / (1999) / Harpercollins
Did you know that lightning bolts can be over a mile long? Or that they may come from
clouds that are ten miles high? Storms can be scary, but not if you know what causes them.
All About Lightning
by Martin A. Uman / Paperback - 167 pages (December 1986) / Dover Pubns
The physics of lightning (voltage, current, charge, speed, event sequence, frequency of
occurrence, length/width of channel, temperature, etc).
of Benjamin Franklin
by Benjamin Franklin / Buccaneer Books / 1996
The Ben Franklin Book of Easy and Incredible Experiments
by Lisa Jo Rudy / John Wiley & Sons / 1995
The Big Idea, Ben Franklin?
Jean Fritz / Putnam Publications / 1976
ON THE WEB:
Franklin Institute Science Museum
A wealth of information on Franklin and Science. Check out the online
version of this Philadelphia, Pennsylvania museum.
A list of Benjamin Franklin's inventions reveals a man of many talents and interests. It
was the scientist in Ben that brought out the inventor. His natural curiosity about things
and the way they work made him try to find ways to make them work better.
From the Microsoft Encarta Online Encyclopedia.
Benjamin Franklin: A
The beginnings of a biography on Benjamin Franklin. Lots of links to sources for this
Known today as "The Autobiography of Benjamin Franklin," this classic piece of
Americana was originally written for Franklin's son William, then the Governor of New
Jersey. This reprint is from the original electronic text distributed by Project
Sources in BOLD Type
page revised January, 2005.
Berners-Lee's invention has revolutionized the world like nothing
The invention of the Internet,
should be classed with the greatest events of the 20th Century.
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book, is the perfect desktop reference for both the science novice and the
technologically advanced reader alike.
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