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Course: The Aspen Institute > Unit 2
Lesson 2: Benjamin Franklin- An introduction to Benjamin Franklin
- Benjamin Franklin becomes a writer
- Benjamin Franklin and Poor Richard's Almanac
- Benjamin Franklin the civic leader
- Benjamin Franklin the inventor
- Benjamin Franklin as diplomat
- Takeaways from Benjamin Franklin's life
- Benjamin Franklin
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Benjamin Franklin the inventor
In addition to his work as a politician and author, Benjamin Franklin was a significant scientist of his era. Many of his inventions were practical in nature, including bifocals and the Franklin stove. He is best known, however, for his experiments with electricity, which proved that lightning was electricity that could be stored in a battery. He invented the lightning rod to deter lightning from striking church towers, which earned him international renown in the eighteenth century. In this video, Sal and Aspen Institute President and CEO Walter Isaacson discuss Benjamin Franklin as an inventor. Created by Aspen Institute.
Want to join the conversation?
- ,,He wanted to explore the effects of lightning, which always strikes the highest point in the area" . Is this why churches, more precisely their bell towers were hit disproportionately higher than other buildings (assuming they were the highest buildings in the area)?(15 votes)
- I greatly enjoy your lessons and especially these on Benjamin Franklin, I have to point out a huge error from an offhanded comment in this lesson. Lightening rods are designed to drain off the charges that build up between the clouds and the earth and by doing this they minimize the occurrence of lightening strikes by minimizing the voltage difference. While they can divert the energy of a lightening strike, when one of these lightening rod systems experiences a direct hit there is more that a 50% chance that great damage will be done to the structure, due to heat and side arcs. So the valid explanation is, (whether or not Ben knew this), lightening rods work by preventing a static build up of energy between the clouds and the ground.(13 votes)
- 'Lightening rods are designed to drain off the charges that build up between the clouds and the earth' can You support that theory with some article?
As far as I know lightning rod provide 'safe' passage for lightning, which would occurred regardless if lightning rod is present or not.(1 vote)
- Wouldn't he have been electrocuted?(2 votes)
- Actually, yes. He was very lucky, in that he was not shocked. Modern Franklin fanatics have attempted to re-create his legendary kite experiment, and they have actually died trying.(7 votes)
- Did they remove the church bells when they discovered that they were making the lightning hit more?(2 votes)
- i think once they understood it installing a ligthning rod to give electricity a safe way down was both more effective and easier than remove the bells, after all even without the bells the tower would probably still be the highest point around and keep attracting ligthning just because of that.(3 votes)
- Was there no electricity before Benjamin Franklin invented it?(2 votes)
- Franklin didn't invent electricity he just discovered that lightning is electricity.(2 votes)
- when Benjamin Franklin flew the kite and it got struck by lightning, how did he not get electrocuted?(2 votes)
- As far as I know, the string was still with rope and rope isn't a strong medium for lighting to pass through.(2 votes)
- was his inventions important in the war?(3 votes)
- I have 2 things: BF saw the wright brother exprimenting with balloons and planes what did he say of them; So he was a practical and humourous man who wants to prank his wife?(1 vote)
- What was bf also? (Civic leader,and ambassador) help(1 vote)
- What does voice over mean in the subtitles(0 votes)
- I Think the voice over is the Aspen Institute President and CEO Walter Isaacson(1 vote)
Video transcript
Voiceover: So in the
last couple of videos, we've talked about Benjamin Franklin as a printer, we've talked about him as a successful public leader, as a successful businessman, but we also
know Benjamin Franklin, and we've talked about him
as a successful writer, with Poor Richard's
Almanac, but there's this other side of Benjamin
Franklin which kind of makes him larger than
life, which he was also a significant scientist. Voiceover: Yes, you know,
he would have thought it was strange that you could aspire to be a great citizen and
not care about science. Back then, you should know about science. So he did everything from tried to track the gulf stream, he
discovered ways to use dark fabrics to absorb heat,
he creates the great Franklin stove, a fireplace
that's a wonderful way to be more efficient
in terms of heating a room without getting
it all smoky, and... Voiceover: And also not wasting the heat I think, normally in a
fireplace all the heat goes straight up, and out. Voiceover: Right, and it
sort of had a nice little top to it, a little plate,
that got very hot, and so he was a very practical inventor. Even things like bifocals,
he's riding along the road one day, and he keeps wanting to read, but then look up
into the distance, and he says, "Well, why
don't I have two pieces "of glass melded together, one that's good "for reading, and one
that's good for looking out in the distance." So, it wasn't like he
was a research scientist, he was just a practical inventor. What makes him into a
great research scientist is when finally, in the
1740s and early 1750s, he starts doing the
electricity experiments. Voiceover: And this is
important, this is actually something I learned
when I read your book on Benjamin Franklin, is that, I mean this was real, as you mentioned, this was real research. This was something that, understanding the nature of elecricity,
the nature of lightning, and how to manipulate it. Voiceover: Yeah, we think
of him as a doddering old dude flying a kite in
the rain, but in fact, those electricity
experiments were the most important experiments of that era. Not only for the practical use of them, but for the theory. Up until then, people had
created static electricity, you know, when you rub
your sweater against a piece of glass, and lots of
sparks come out, and they thought that electricity
was two different fluids, and they had two different
names for the fluids. Franklin realizes it's
a single fluid, and he creates the idea of positive and negative, plus and minus, those
type of things, so that it's a flow of electricity,
and he does that with his electricity
experiments that really begin in the 1740s, partly as
a parlor trick, 'cause he loves it, but then he
realizes, no, let's study this stuff - electricity. Voiceover: And it was a
real issue, I mean people were dying because of lightning. I remember in the book,
there was a particularly funny, I forgot the exact
quote, where he said, "Churches get to be, tend to be hit "disproportionately, so it seems like God "is not favoring them." (laughing) Voiceover: Right, well you
know what they used to do, was they would sanctify
the church bells, so that it would ward off the
lightning, and they would even sometimes store gunpowder inside churches with sanctified bells. But the lightning kept
hitting the steeples of the churches, and people in
Germany, Italy, and then the United States, there
were these huge explosions, lightning was the great
scourge of the times. Voiceover: So to ward off lightning, they would sanctify a metal bell, and put it at the top of the tower. Voiceover: Bingo! (laughing) It did not work! And Franklin has a wonderful
line in one of his letters which is, "You'd think
we would try something different, and see if
that worked." (chuckling) And so Franklin looks at
sparks, that he's been looking at from his
electricity experiments, and he's been creating these little sparks with the static
electricity, but then using wire to make it into
a flow of electricity, and put it into a battery. He gives us the name "battery" 'cause he puts it together a lot of Leyden jars, which is the way they
used to store electricity. And so he's looking at
the similarity between sparks and lightning. And in his notebook, he
makes a little chart. He said, well sparks have these qualities, they're fast, they jump,
there's a sulfurous smell, they make a little
crack, and lightning has the same qualities. And he does a wonderful
notation at the bottom of that notebook page,
very scientist-like, he says, "Let the experiments be made." And that's how you get
the lightning experiments. Voiceover: He literally,
it's a little bit of a legend now, but he
literally did go out into a rainstorm and tie a
kite with a silk thread, to a kind of a key
attached to a Leyden jar? Voiceover: Well, what he did was as clouds were passing over, he and his son William went out into a field,
and as the rain started, they flew the kite, and
they tried to draw the electricity down from
the clouds, 'cause it was his theory that a
lightning strike was just a spark coming out of a cloud. And at first it didn't
work, but as the cloud got nearer, he could see
the little fibers on the silk get raised, and
there was a key at the end of it, and that's where the electricity, the charge collected, and then he was able to put it into a Leyden jar, or a battery. Voiceover: So really what
he was doing, is he was connecting, because the
clouds are getting a, they're kind of at a different electric potential up here, by
kind of connecting it with his conducting
silk thread that's wet, he was able kind of to get the Leyden jar to save potential. It wasn't like the lightning
struck like Back to the Future. Voiceover: No, it wasn't like lightning striking him,
he was drawing some of the charge down from
the cloud, but that showed him that what
lightning was, was a discharge from the cloud of its electric potential. Voiceover: Right, and that's significant, 'cause when he figured
that out, that you could manipulate electric, that
lighting was electricity, that he could kind of
solve the church problem. Voiceover: The big, big
problem, and you look at that kite you've drawn, what
does that show you? It says, I get it, if we put
something up there like that, like a lightning rod,
and he knew that pointed metal objects were very
good at drawing the flow of electricity, so he
said, why don't we put up a lightning rod, and he
described exactly how to do it. They ended up testing it
in France, first, 'cause he published the lightning
rod way of doing it, but later on he replicates the experiments in the United States,
and it makes him the most famous person probably, other than maybe the King of France, and
the King of England, the most famous person
in the world because he has solved this
astonishingly big problem of how do we ward off lightning from striking our building. Voiceover: Especially tall buildings like church and castle towers, and this is where he saves lives, this is a... Voiceover: Oh saves hundreds of lives, by far the most important
invention of the time, and of course, we still
use lightning rods, we still ground, have
grounded points on top of buildings to make sure... Voiceover: It's a very
simple idea, that you give kind of this pointed conductor point, that's really high up,
the lightning will want to strike that, and then
you construct a path for the lightning, so
it can go to the ground, and not have to go through the building. Voiceover: And what he does in his house in Philadelphia, especially
'cause he's about to go to England again at the time, he puts up a lightning rod, he
grounds it, but he puts a tiny little bell, so
that when the electricity's coming down from the storm is approaching, and it's drawing the electrical charge from the clouds, a tiny
little bell will sort of bounce back and forth, being jolted by the charges coming there, and
it drove Deborah Read, his wife, absolutely to distraction, so there's a wonderful
letter he writes home from England, telling her how to dismantle the bell, and it will still be safe. Voiceover: Fascinating.