Lesson Plan - Get It!
When electricity was first discovered, the feeling must have been electrifying!
While this energizing discovery caused great excitement as it changed the world, it also brought confusion and misunderstanding.
- When did this zapping story about electricity begin?
- Who were the people behind it?
Let's find out!
- Have you ever flown a kite?
Scientist Benjamin Franklin is often shown flying a kite.
- What does this have to do with electricity?
Many people associate the image of Franklin flying a kite with the invention of electricity. However, Franklin did not actually invent electricity. He simply discovered it!
Electricity has always existed. Studies have shown that, even as early as 600 B.C., people were intrigued by this unknown phenomenon. In ancient Greece, they would rub fur on amber to observe what we now know is static electricity!
Amber is a fossilized resin from wood. Resin is a sticky substance in which insects or plant debris can easily get entangled, and eventually trapped, as it dries out. When rubbed with fur, they become attracted to each other. This was the first recorded history of electricity!
Benjamin Franklin: Shock and Awe
When people talk about electricity, they always mention Benjamin Franklin and the iconic image of him flying a kite as lightning strikes in the background.
One June afternoon in 1752, as the skies began to darken over Philadelphia, Franklin supposedly conducted an experiment to prove that lightning is electrical in nature. He tied a metal key to a kite and let it fly during a thunderstorm!
Many of the stories mention that the key was struck by lightning. If that were true, Franklin would have been electrocuted.
- So, how did he prepare for this death-defying experiment?
He made a simple kite and attached a wire to its top as a lightning rod. At the bottom of the kite, he attached a hemp string and then a silk string, which was the part attached to the door of his shed. He used silk string because it remains dry. The last step was attaching the metal key to the hemp string.
Later, he noticed that the loose threads of the hemp string started standing erect. He then placed his finger close to the key and...voila! There was a spark!
He was in awe of, and had a literal shock from, this promising appearance!
Franklin then used a Leyden jar to collect the "electric fire" from the key. A Leyden jar can trap high-voltage electricity so that it can be held and discharged at a later time.
Image by James Edward Henry Gordon, via Wikimedia Commons, is in the public domain.
The Thread-Rising Experience
Franklin's experiment only increased his interest in electricity.
In fact, he turned his home on Market Street in Philadelphia into a laboratory where he designed instruments using available household items. He even used a wire leading from an iron rod attached to his chimney to carry electricity inside his home.
This rod and the key in a lightning storm may sound unsafe, but the truth is much calmer than the lightning bolts of electricity retold in the stories.
No lightning actually hit Franklin's iron rod or metal key. Instead, there was a buildup within clouds of electrical charges that were on the verge of being discharged to the ground in the form of lightning.
Some of these charges were encountered by the kite and rod. This was evidenced by the spark produced by the metal key and the loose hemp thread rising in the kite experiment.
When Franklin used the Leyden jar to collect these charges, he also proved that electricity as we know it can be collected, stored, and distributed later.
To learn more about this electrifying story, you can read The Electric Ben Franklin, from Independence Hall Association, or watch Franklin's Discoveries, from Bobblehead George:
The Century of Enlightenment
About 15 years later, a British chemist named Joseph Priestley published an account of Benjamin Franklin's experiment along with other "discoveries" of electricity in The History and Present Stare of Electricity, With Original Experiments.
During the 18th century, many scientists struggled to understand electricity's natural properties, such as attraction and repulsion. Benjamin Franklin coined the following terms that we know today:
- plus (positively)
- minus (negatively)
Benjamin Franklin went on to design the lightning rod, an iron rod attached to the top of a building and connected to a wire. The wire-transported lightning strikes harmlessly to the ground. Before this, buildings struck by lightning often caught on fire.
This was a remarkable discovery, and many tall structures and skyscrapers in the United States and Europe still use lightning rods.
Clearly, Franklin didn't discover electricity. However, he was the first to create a hypothesis about lightning and electricity, and then he conducted successful experiments to prove it!
When you are ready, keep going with the Got It? section!