Untitled Document

02 August 2002

Shawn's NPR Interview

AIR DATE: June 28, 2002 Friday

SHOW: Talk of the Nation/Science Friday (2:00 PM ET) - NPR
HEADLINE: Shawn Carlson discusses Ben Franklin's many scientific achievements
ANCHORS: IRA FLATOW
IRA FLATOW, host:
You're listening to TALK OF THE NATION/SCIENCE FRIDAY. I'm Ira Flatow.
And for the rest of the hour, we're going to take you back to a grade school history lesson, Ben Franklin's famous kite experiment, because it's the anniversary of that, 250th year. Well, we'll find out exactly when and maybe--we don't know where--when it exactly happened. But, you know, Ben Franklin gave us such quotable quotes as "An ounce of prevention is worth a pound of cure," he worked as a printer, storekeeper, publisher, he owned the Philadelphia Gazette, he published Poor Richard's Almanac, he was a statesman, helping to draft the Declaration of Independence, he was an inventor--you've heard of the Franklin stove, of course--as well as he invented swim fins and bifocal glasses, among all kinds of inventions that are too numerous to get into. But my next guest says that despite all these accomplishments, Ben Franklin considered himself first and foremost to be a scientist. He made many contributions to our understanding of electricity, including his famous kite experiment done 250 years ago, and that captured electric fire from a storm cloud and stored it in a jar, proving that lightning was a form of electricity, just like from other sources on Earth. It's that experiment, Ben Franklin's other scientific achievements that we'll be talking about the rest of the hour. Give us a call. Our number is 1 (800) 989-8255; 1 (800) 989-TALK.
Let me introduce my guest. Shawn Carlson is the founder and executive director of the Society for Amateur Scientists in East Greenwich, Rhode Island. He joins me today from the American Philosophical Society in Philadelphia, the organization founded by Ben Franklin.
Welcome back to the program.
Mr. SHAWN CARLSON (Founder and Executive Director, Society for Amateur Scientists): Thanks, Ira. Good to be here.
FLATOW: Do we know the exact date of that kite-flying experiment?
Mr. CARLSON: No, we don't. We only know that it was sometime in June of 1752. Franklin never reported the date.
FLATOW: In fact, we only know about--how do we even know about the experiment?
Mr. CARLSON: Well, there was a published report in a newspaper that was sometime after the experiment, and then 15 years later, Joseph Priestley did an extensive scientific discussion on the subject, which Franklin knew about and he certainly got all the first-hand information from Franklin. So we have Priestley's account as the most complete.
FLATOW: Take us back to that colonial period. What was all this excitement about lightning and electricity and things like that?
Mr. CARLSON: Well, when Franklin got involved in the study of electricity, the subject was nothing more than a collection of clever parlor tricks. I mean, what, for instance, people--you know, traveling showmen would charge up a Leyden jar and then have everybody in the audience hold hands and then discharge the Leyden jar through the audience, thereby electrifying the audience. That's, in fact, where the phrase comes from. So they did all of, you know, these traveling hucksters and shows and stuff. And Benjamin Franklin was the first person to take all of these very different phenomena that had been known about since the time of the Greeks and unify them into a single description that actually had predictive power. So Benjamin Franklin laid the foundation of our modern understanding of electricity and magnetism.
FLATOW: So he did not discover electricity or invent electricity as we've--people...
Mr. CARLSON: Certainly not. It had been known from the time of the Greeks that if you rub amber, it would attract small--you know, hair and small pieces of parchment. But Franklin was the first person who laid a theoretical framework down, and it's still basically the foundation of our modern understanding. Now Isaac Newton had tried to solve the same problem and had never succeeded at it. So when Franklin came up and, through his brilliant theories of systematic experiments that he did over several years, you know, quietly in his home in Philadelphia, when he was able to unify all of this and come up with a coherent explanation that bested the most esteemed scientists in Europe, you know, his career just absolutely skyrocketed. And when he invented the lightning rod and when his people conducted the experiment that he suggested to draw down electrical fire from the clouds and, thereby, conclusively proving that lightning was just a form of electricity, Franklin became one of the most well-known scientists in the world and certainly amongst the most esteemed scientists in the world of that time.
FLATOW: In fact, the French did his experiment before he did, right?
Mr. CARLSON: That's true. The French did a variation of the experiment. Now Franklin published a description of an experiment that's now called the sentry in a box(ph), where he said, take a long conductor, put it alongside a church and then have somebody draw sparks off of the bottom of the conductor in an enclosed area, a little alcove, so that when a--normally you can't do that unless an electrified cloud comes over, so that would electrify the air, the pointed conductor would take up some of that electricity and transfer it to the sentry who was monitoring the box. That was the experiment that proved conclusively that thunderclouds did electrify the air, and that was the one that was done by the French in May of 1752.
Now word traveled slowly in those days, so Franklin did not know that he was already becoming famous in Europe. In June, when he realized that he could do the experiment in a much more simple way, mainly by flying a kite up to the cloud, have a conducting wire at the top--he knew that when the rain came down and wetted the cord, that then the kite string itself would become conducting, and then that carried the electricity to a kite that he had tied off at the bottom of the string, and then he was able to draw sparks from his knuckle and thereby establish again the connection between electricity and lightning.
FLATOW: And, of course, when the French did it beforehand and showed that Franklin was right, he became a celebrity in France, didn't he?
Mr. CARLSON: Overnight. He became one of the most famous men in France. As a matter of fact, when he was lobbying for the French support in the Revolutionary War some years later, he was so famous in France that people started putting his portraits on everything, and there was a time when it's possible that there were more portraits of Benjamin Franklin in Paris than there were of the king of France.
FLATOW: Wow.
Mr. CARLSON: And so he was just extraordinarily--I mean, no diplomat or scientist has ever been able to match that kind of a claim in a foreign country.
FLATOW: You know, Isaac Asimov wrote a little book once called the "Kite That Won the Revolution." Do you think that would be fair, that because of that experiment he was able to get in to see the king of France and get support for the Revolution?
Mr. CARLSON: Well, Franklin had been--I mean, Franklin was the son of an English candlemaker, so he was very much part of the working class and the trades class, and he had spent years doing, you know, civic works, trying to work his way up the political ladder. But he never managed to break through until people started giving him honorary degrees and, you know, screaming his praises all through Europe. Then suddenly the political elite in colonial America recognized what an asset they had, and only then was he elevated to the level of statesman and did we get to see him--you know, did he get a chance to apply his extraordinary political and statesman skills.
FLATOW: Wasn't there one scientist--Was it a Russian scientist?--who didn't ground his--or grounded his experiment and was electrocuted by it, if I remember correctly, reading?
Mr. CARLSON: Well, there are--well, first off, I gotta tell you that the kite experiment never killed anybody, so far as I know.
FLATOW: So lightning never struck the kite, right?
Mr. CARLSON: Lightning never struck the kite. Franklin made sure to fly the kite well in advance of the clouds that were actually delivering lightning. He knew that it took an awful lot of charge to break down the atmosphere and deliver a strike, so he hoped that one cloud over, there would still be electrical charge, that that cloud would still be electrifying the atmosphere, just not enough to kill you, OK? So no one got killed doing that experiment, because whenever the, you know, cloud came, you know, and lightning struck too close, you released the kite. But it is true that there was one scientist who was in a sentry box, and lightning actually struck the conductor at the time that he was in it and he was killed.
FLATOW: 1 (800) 989-8255 is our number. Let's go and see if we can get a call or two. Paul in Spring Arbor, Michigan. Hi, Paul.
PAUL (Caller): Hi. How are you?
FLATOW: Hi. Go ahead.
PAUL: It's good to talk to you.
FLATOW: Thank you.
PAUL: I'm reading "The First American" now, and what an amazing story, this guy.
Mr. CARLSON: Great book.
PAUL: Yeah, it is. It is. It's just fascinating. In the book, and in your discussion today, you talk about the lightning bottles and in the book they talk about getting them fully charged in order to do these parlor tricks. And I don't understand how they get charged.
Mr. CARLSON: Well, they knew that you could bleed off a small amount of charge by friction, and so they had a rotating glass drum which was usually cranked by hand. Matter of fact, one of Franklin's innovations was to add a clutch which allowed you to go faster and faster and faster without destroying your arm. And so typically you would then rub it with your hand and then you would touch one side of the jar with a metal conductor and it would transfer the charge, you know, from the rotating drum to the Leyden jar. That was typically how it was done.
PAUL: Wow.
FLATOW: And the jar basically had--What?--foil on the inside, then there was a glass for the jar, and then foil on the outside or something?
Mr. CARLSON: Yeah, basically it had foil--essentially it was just a glass jar with foil on the inside and the outside filled with, usually, water. And so you would dump the--there was a conductor that went into the water, and so the charge flowed in, flowed out to the foil on the inside, an opposite charge appeared on the outside, which was grounded, and then that was how you stored the energy.
FLATOW: OK, Paul?
PAUL: This is not static electricity.
Mr. CARLSON: Static electricity, right.
PAUL: It is? Oh, OK. So that's how the glass tubes that they used worked. They were just static electricity, just rubbing the tube against your clothes or something.
Mr. CARLSON: Exactly like rubbing your feet on a carpet and going over and touching a doorknob.
FLATOW: And let me just jump in here and say I'm Ira Flatow, and this is TALK OF THE NATION/SCIENCE FRIDAY from NPR News.
And the breakthrough that Franklin made was showing that that same static electricity you got on the carpet there was what was coming down from the sky also, right?
Mr. CARLSON: And as a matter of fact, it was more than that, because what Franklin was able to do was he was able to show that if you put a large, tall conductor that was pointed at the top against your barn, what it would do is bleed off charge from the ground--now when a cloud goes over that's highly charged, a mirror charge shows up in the ground beneath it, and when the potential between those two gets large enough, that's when the lightning happens. So what happens is the large conductor being grounded, the tall conductor that's pointed, draws charge up and slowly bleeds it off into the atmosphere and sort of, like, deflates the electrical balloon. And as a result, it makes lightning strikes much less likely. Most people think that lightning rods are designed to attract electricity. That's not what they're designed to do. They're designed to prevent lightning strikes in the first place.
FLATOW: And he also discovered that the lightning travels from the ground to the cloud as opposed to what we normally think, that big bolt.
Mr. CARLSON: Well, he found out that you could get strikes in both directions...
FLATOW: I see.
Mr. CARLSON: ...that it could go from the cloud to the ground or from the ground to the cloud.
FLATOW: Dudley Herschbach, who is a Nobel Prize-winning chemist--I've spoken with him many times over the years--he says that Einstein was--Enstein--confusing the two--that Franklin was the greatest American scientist we ever had. Would you agree with that?
Mr. CARLSON: I would say that Franklin is in the short company, he's on the short list of the greatest scientists we ever had. If you look at the scope of Franklin's achievements, it wasn't just his extraordinary work that he did in electricity. He was also the first person, for instance, to understand that weather just didn't happen locally, that a storm that you experience today might be a hundred miles over tomorrow, and he was the first person, using his position as postmaster general, to track a hurricane going up through the colonies. He was the first person to study the sociology of insects. He was the first person to analyze the teeth of a mastodon and figure out that the climate in Siberia, where the mastodon had been found, must have changed, so that meant that climate was not something that could be relied on as being constant all over the world. So even Franklin and, of course, Thomas Jefferson and others in that time were concerned about those issues even back then.
FLATOW: We've got about 20 seconds left. I know you have a conference going on.
Mr. CARLSON: Yeah, that's right. Since we did so--for the 250th anniversary I decided we would take some of the greatest amateur scientists' minds from around the country and bring them here to Philadelphia to celebrate. And if I can, tomorrow, we actually have a free lecture for any of your readers. If you're within driving distance of Philadelphia, Jerry McDonald, one of the greatest citizen scientists of all time, is going to be talking about his extraordinary discoveries in paleontology tomorrow at noon in Logan Hall here on the University of Pennsylvania campus.
FLATOW: Of course, Franklin was the ultimate amateur scientist, wasn't he?
Mr. CARLSON: He is the icon, he is the image upon which we all aspire.
FLATOW: Shawn Carlson, thank you very much.
Mr. CARLSON: It was a real pleasure, Ira. Thank you.
FLATOW: And have a good conference.
Mr. CARLSON: Thank you.
FLATOW: Founder and executive director of the Society for Amateur Scientists in East Greenwich, Rhode Island. Earlier we spoke with Inder Verma, the American Cancer Society professor of molecular biology and co-director of the Laboratory of Genetics, Salk Institute for Biological Studies in La Jolla, and Michael Oppenheimer of Princeton University.
(Credits)
FLATOW: If you'd like to write us, you can surf over to the Web and leave us e-mail at sciencefriday.com. If you missed any of the links or you want more information about what we talked about this hour or you want to listen to archival versions of SCIENCE FRIDAY, you can surf over to our Web site and find out where those things are located on the Web site and click over to those links. Or you can send us e-mail to TALK OF THE NATION/SCIENCE FRIDAY; by snail mail, of course, 1 Centre Street, New York, New York 10007. Have a great weekend. I'm Ira Flatow in New York.

Copyright 2002 National Public Radio (R). All rights reserved.