Benjamin Franklin was a leading author, political activist, publisher, scientist, diplomat and much more. He was one of the Founding Fathers of the United States. Here, in this post, we will talk about his seminal contributions to electricity.
Photo Courtesy: Wikipedia
Benjamin Franklin was born on 17th January 1706 in Boston Massachusetts. Due to financial constraints he could not graduate from Boston Latin School. However, he was a voracious reader and this compensated for formal education. His love for electricity started in 1743 after attending a lecture by Dr. Archibald Spencer. Dr. Spencer was famous for showing tricks using electricity.
Conservation of Electricity
Benjamin Franklin was the first person to coin and use the terms positive and negative charge. He discovered, through experiments, that electricity is not generated by rubbing two objects, but is rather transferred from one object to the other. Franklin also discovered that positive and negative charge is always balanced in all objects in nature. This balance is achieved by transfer of positive charge from a higher charged to a lower charged body. This is called Principle of Conservation of Electricity. Ben Franklin was the first person to use the terms charging and discharging while describing transfer of electricity. (Read more on battery Charging and Discharging)
Ben Franklin built an electric battery using glass window panes and thin lead plates. Using his “electric battery,” a term he coined himself, he showed how electricity could be stored in the glass and passed through it. Shouldn’t we call it the great-grand-dad of electric batteries?
Leyden Jar Experiments
During Bejamin Franklin’s time, Leyden Jars were used to store and transfer electricity. These jars were made of glass, covered with metal foil on the inner and outer surfaces and filled with water. Franklin did extensive experiments with Leyden Jars and discovered that the electricity was stored in the jar rather than water, as was believed. He found that jars could be made of any material. However, the amount of electricity stored would depend on the type of material used.
One of the most famous experiments done by Benjamin Franklin was the Kite Experiment. He attached a long wire to a kite made of silk. He used it to draw electricity from storm clouds and charge a Leyden Jar. Through his experiments, he proved that storm clouds carried electricity and lightning was nothing but a heavily charged spark of electricity. This was a path breaking discovery of his times because in those days thunder storms and lightning strikes caused widespread damage to wooden structures.
Franklin built a setup called Franklin Bells which served as a warning for approaching thunder clouds. He also used the setup to collect charge and use it for other experiments.
Photo Courtesy: www.rmcybernetics.com
The Lightning Rod
Franklin discovered that when a pointed object is held towards a charged object, it draws electricity from the object. After the Kite Experiment, he wondered if a metal rod could be used to draw electricity from the thunder clouds. That was the birth of lightning rod!! He constructed the first lightning rod to be installed at tops of buildings. These rods transferred the sudden burst of electricity discharge and passed it to the ground through a wire without causing any damage. It is still used in buildings today. (You can make your own mini-lightning following these instructions).
You should remember that all the electricity and electric charge we are talking about is static. i.e. there is no flow of electric current. That came only with the invention of voltaic pile by Alessandro Volta. Benjamin Franklin died on 17th April 1790, leaving a legacy of inventions to be used and refined upon by others. A few of his inventions, other than those mentioned above, include bifocals, street lights, Franklin stove, glass armonica, and the carriage odometer.