By Don Lincoln, Ph.D., University of Notre Dame
There is a famous story about lightning: Benjamin Franklin flew a kite into a thunderstorm and collected lightning in a jar. This could be true in a magical world but not in the world of science. Another common misconception is that passing through a thunderstorm in a car is safe because the rubber tires do not let the electric charge get the people. In a world of science, is that really the case?
Lightning has fascinated people since the beginning of life. There are numerous myths about it, and some are even made in modern times. Not knowing the reality behind these myths can lead to serious injuries and sometimes even death, as in the case of Georg Wilhelm Richmann, who got struck by lightning and died. There are two popular stories about lightning and thunderstorms, both of which are wrong to some extent.
Learn more about What the World Gets Wrong about Science.
Franklin’s Kite
Benjamin Franklin was a scientist of the 1750s, who is known as the discoverer of electricity. In June of 1752, he experimented with a kite and a thunderstorm. The story has it that he got two light strips of cedarwood, big enough to cover a large silken handkerchief. He chose silk because the paper would be subject to getting wet and tearing in a rainstorm. This kite was then tied to a hemp string, and the hemp string was tied to a key. Finally, a silk ribbon was tied to the string.
To attract electricity, Franklin put a metal rod on the kite that extended from the top. This was the first lightning rod, and the reason many houses got lightning rods later to stay safe from lightning electricity.
This is a transcript from the video series Understanding the Misconceptions of Science. Watch it now, on Wondrium.
Franklin took his silk kite into a rainstorm before the rain started, stood fully under shelter to keep himself and the silk ribbon dry to stay safe from the lightning electricity passing through the wet ribbon and his hand. He flew the kite into a thundercloud, and before the rain began, put his hand close to the key and felt a spark. Up to here, the story can be true.
The peak of the story is when a flash of lightning struck the kite, ran down the string, and jumped off the key. Thus, the lightning was trapped in a glass and metal contraption called a Leyden jar, which was used at the time to ‘store’ electricity. This is where science steps in.
The Scientific Explanation of Franklin’s Kite
Assuming a kite that small can even fly, and assuming that it did fly into a raincloud and that the lightning bolt ran down the string, keeping the lightning away from Franklin was impossible. Staying dry can by no means keep 100-million-volt lightning from striking the person holding the string. A Baltic-German physicist called Georg Wilhelm Richmann died performing the same experiment.
Franklin did advance the lighting rod technology, but the kite story cannot be scientifically true under any circumstance.
Learn more about From the Sky Down: How Falling Works.
Passing a Lightning Storm in a Car
Another misconception is that it is safe to drive through a lightning storm since the rubber tires are good insulators and prevent the lighting’s electric charge from entering the car. The theory is scientifically true in the face of reasonable voltages – for example, 120 volts coming out of an outlet in the wall. However, lightning carries almost 10,000 amperes of current, 100 million volts, and generates temperatures in the several thousands of degrees Fahrenheit. Can rubber insulate this?
The Scientific Explanation of Passing a Lightning Storm in a Car
The rubber tires cannot withstand 100 million volts. However, driving a metal car is really the safest way to pass through a storm. Firstly, metal is an excellent conductor. So, if lightning strikes the car, the metal tends to conduct the electricity down into the ground.
The second reason refers to the Faraday cage. Faraday cage explains that when an electric charge is put on a metal shape, it moves around the shape to end up at the outer part of the shape. The same thing happens in the car.
Learn more about Myths of Orbital Motion.
Common Questions about Lightning
The general answer is yes, but lightning does not necessarily kill everyone that it hits. There is definite harm, but the seriousness varies depending on the strength of the lightning, the situation, and how it strikes a person.
Nothing really attracts lightning to a person, not even wearing metal jewelry. However, the possibility is high on open and vast areas like golf courses. Shelters, especially metal ones, can keep people safe from a lightning strike.
A car is an extremely safe shelter from lightning. Going through a thunderstorm with massive flashes in a car is the safest way to pass it, as the electric flow hits the car and stays there for two reasons: the metal around is a much stronger conductor than the people inside, and the charge tends to move to the outmost layers. Thus, rubber tires play no role at all.
Lightning is an electric current and the result of tiny frozen raindrops collision. When the small pieces of ice bump into each other as they move around in the air, the collisions create an electric charge. Slowly, the whole cloud is full of electric charges, and lightning occurs.
