The first day of summer is nearly here, and the calendar is already dotted with stormy days from all over North America. The next lightning storm that passes through your area may give you a moment to reflect on a legendary tale of American ingenuity -- Benjamin Franklin’s kite and lightning experiment of June 10, 1752.
Not So Fast
Many of us heard simplified versions of this tale as children. Benjamin Franklin tied a key to a kite and flew it during a thunderstorm, discovering electricity when the kite was ultimately struck by lightning. But that version is inaccurate in many ways, not the least of which is that a direct lightning strike would almost certainly have killed Franklin, who lived to tell the tale.
Some historians maintain doubts about whether Franklin conducted the experiment at all, but even if he did, he wasn’t the first to experiment with lightning’s electrical effects. Scientists in Paris documented their efforts to harness lightning with a metal rod just weeks before Franklin’s famous kite flight.
The Famous Experiment
Franklin doubted his ability to extend a metal rod high enough to harness electricity from the ground, but felt he might be able to do so by flying a kite. When a storm descended upon Philadelphia on June 10, Franklin and his son, William, launched a silk kite into the stormy skies.
The kite had two strings -- one made of silk, and a dampened string made of hemp. William steered the kite from inside a shelter by holding the dry silk line, which was intended to shield him from electrical shock. The dampened hemp line was attached to a metal key, and further down the line, to a Leyden jar -- the closest thing to a battery to exist in the 1750s.
While the kite itself was never struck by lightning, Franklin deduced that it did collect electrical energy from floating around amid an electrical storm. He reported that the frayed ends of the fibers in the string repelled each other, and as he reached toward the key, it produced a visible electric spark.
While the popularized version of this story may inaccurately recognize Franklin as the man who “discovered” electricity, the Founding Father did contribute significantly to electrical science. Most importantly, Franklin invented the lightning rod three years before his kite experiment and improved upon the design throughout the rest of his life.
Prior to the spread of lightning rods, fires caused by lightning strikes were common in taller structures. But with a lightning rod properly installed, there was a chance the rod would intercept a lightning strike and direct the current safely to the ground, protecting the structure.
In writing about his experiments, Franklin also contributed to electrical science by coining several of the terms we use to talk about electricity today, including “battery”, “conductor”, “charge” and “armature”.
We’ve come a long way since Franklin’s pre-Revolution experiments, but considering his contributions to the field, we all owe him a debt of gratitude every time we flick the switch and the lights come on. If your home electrical system isn’t doing Mr. Franklin’s memory justice, reach out to your licensed, local electricians for help.