Benjamin Franklin’s kite experiment is often depicted wrongly – what does that mean for how we teach science?

Benjamin Franklin strode outside one day in 1752, flew his kite in a thunderstorm, and discovered electricity when it got struck by lightning. Right?

Well, no. There are several inaccuracies in that sentence. Franklin performed the experiment while remaining under shelter, there was no lightning strike, and he certainly didn’t discover electricity – he just confirmed the link between lightning and sparks made by other things he and his peers had been tinkering with, like Leyden jars.

But if you held any of those misconceptions, you’re not alone.

In fact, according to Dr Breno Arsioli Moura, an assistant professor at the Federal University of the ABC in Brazil, people have been depicting errors in the kite experiment for nearly 200 years.

He’s recently published a paper on drawings of Franklin, and their many errors, in Science & Education.

“It is amusing to see Franklin flying a kite in the middle of a storm,” Moura tells Cosmos.

But it’s not really true – that would have been both dangerous and pointless.

So what really happened, and why does it matter?

Franklin’s kite experiment

The kite experiment is a simplified version of a previous test Franklin and his peers had done, called the sentry box experiment.

There are two records of the experiment that most people rely on for information. One comes from Franklin’s letter to British botanist Peter Collinson in 1752. The second was published 15 years later, in Joseph Priestley’s The History and Present State of Electricity: an account generally believed to have been read and approved by Franklin before publication.

In Franklin’s version of the story, the experiment is done with someone standing indoors, flying a kite with a wire attached through an open door or window. The kite’s twine is tied to a key, which is then tied to an insulating silk ribbon held by the experimenter.

Benjamin franklin's kite experiment: flying kite outside as lightning strikes it, boy watches on
Alfred Jones’ vignette, produced for the American Bank Note Company, and one of the several images Moura studied – there are a few inaccuracies in it. Via Wikimedia Commons

When a storm approaches, the kite is electrified by just the presence of the clouds, and falling rain makes the kite’s twine wet so that it conducts electricity. The person holding the kite should be protected from the charge, but will be able to get a small spark to leap from the key when they hold their finger near it.

Priestley’s version is more detailed, and emphasises different things: it downplays the fact that the person must be indoors, and includes Franklin’s son in the story – presumably William Franklin, since his other son Francis died in 1736.

It also ambiguously implies that lightning struck the kite, saying “lightning descended by the hempen string”. This wasn’t actually the aim of the experiment – the sparks should have been possible without a lightning strike.

That’s how it was recorded as done – but how has it been illustrated?

Drawing flaws into the kite experiment

Benjamin franklin flying kite outside tied to post with boy looking on, touching key to post
Another of Moura’s studies: Henry G. Hine’s engraving published in John Henry Pepper’s 1860 book ‘The Boy’s Playbook of Science’. Via / Getty Images

Moura went looking for widely-used illustrations of Franklin’s kite experiment. He couldn’t find any from the 18th century (although there are pictures of other similar experiments), but there were several from the 19th century.

Moura chose seven that were readily available, of sufficient quality to analyse, and the sort of thing likely to be used by teachers to illustrate points.

According to Moura, all of these illustrations appear to have been influenced by Priestley’s account, although they could have seen it filtered through other reports.

The pictures carry some clear historical errors – they mostly depict Franklin’s son as a boy, for instance, but he would have been 21 at the time – but there are also plenty of problems with the experiment itself.

Six of the seven illustrations see Franklin and his son standing outside, which would have rendered the experiment pointless: if the silk ribbon got wet, it would stop working as an insulator and let the electricity get grounded.

In fact, most of the pictures miss the point of the silk ribbon entirely, depicting Franklin as holding the string, again wrecking the experiment.

(It wasn’t included in his study, but Moura points out Benjamin West’s famous 1806 painting got the strings right – although the frolicking naked cherubs are presumably artistic license.)

Benjamin franklin surrounded by cherubs producing a spark from a key hanging from a kite
This 1806 oil painting by Benjamin West wasn’t included in Moura’s study, but it does get the key detail right. Via Wikimedia Commons

Perhaps most dramatically, three of the pictures show lightning striking the kite, which in reality would have deadly consequences. This is a particularly dangerous and pervasive myth, which Cosmos itself has reported in the past.

Moura says that he’s not analysed 20th or 21st century depictions, but there are some that are more accurate.

“For instance, in my paper, I mention one made by John Keay. There you can clearly see two different coloured strings. There is also a mural in Benjamin Franklin Institute of Technology in Boston which is very accurate as well, at least in terms of the shelter and the age of Franklin’s son.”

Why does this matter?

Lithograph of benjamin franklin outside flying kite with son
Another of Moura’s studies: Émile Bayard’s 1879 illustration, published in Le Roy C. Cooley’s Natural Philosophy for Common and High Schools. Via / Getty Images

Franklin isn’t the only victim of inaccurate depictions in science – Moura is actually at the beginning of a whole book on iconography in 18th-century electricity.

“I believe these images contribute to an ‘ideal’ or maybe ‘heroic’ version of scientific work. They are easy tools to propagate the idea that science is often made by chance and only by geniuses,” he says.

Pictures are used so frequently as educational tools, there’s a risk that inaccuracies in them can play into this iconography.

“The teacher may say: ‘See? Franklin went there during a thunderstorm, flew a kite and discovered electricity!’. While this might be amusing and fun, it is also distorted and wrong,” says Moura.

“We should teach how science is really done, how scientists are influenced by cultural, social and political contexts (like Franklin was), how scientific discoveries are very often not isolated, how scientific experiments had previous history.

“This is real fun.”

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