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05/30/2002
Lightning and Chatting with Ben
The thunderstorm season is upon us and one is predicted for
today here in New Jersey. While the lightning associated with
these storms does us good in that it helps "fix" nitrogen for use in
growing vegetation, it can be scary. I''ve had a couple close calls
myself. One day a few years ago, it was around noon when the
wind started to blow furiously and the sky turned ominously
dark. My wife and I opted to go to our basement and just a few
seconds later, lightning struck a neighbor''s tree some 50 feet
from our house. Fortunately the tree fell away from our house.
There was also the time I was golfing with Brian Trumbore when
lightning struck so close that the foursome ahead of us on the
green felt electricity in their putters! Back in the days before
jets, I was on a prop plane preparing to land at Newark Airport
when there was a "WHUUUMP" and the plane shuddered. The
pilot reassured us, saying, "Don''t worry. That was just static
electricity!" I thought hey, that''s lightning in my book!
These personal experiences with lightning pale when compared
with the significance of what happened just 250 years ago this
June. If you look at the last page of the June/July issue of
American Heritage magazine, you''ll find an item by Frederic D.
Schwarz on possibly the most famous episode in the scientific
study of lightning. I''m talking of course about the time that
Richard Saunders flew his kite. If the name Saunders doesn''t
ring a bell, perhaps you might recall that he wrote articles for a
publication called Poor Richard''s Almanack. Among his entries
in this publication were such well known sayings as "God helps
them that help themselves." or my favorite "He''s a fool that
makes his doctor his heir." As you''ve no doubt surmised,
Richard Saunders was the pen name used by one Benjamin
Franklin.
Now I don''t mean to be a name-dropper but just a couple weeks
ago, back on May 15 to be precise, I was in Philadelphia and
actually had the opportunity to chat with old Ben himself. The
occasion was the party and banquet celebrating the 100th
anniversary of the founding of The Electrochemical Society
(ECS). For me personally, this ECS meeting marked the
culmination of a project that had occupied a major portion of my
time for the past year and a half or so - the writing and editing of
a centennial history of ECS. Each registrant received a copy of
the result of this effort. I was amazed and delighted to see what
Mary, the ECS publication manager, and her staff had turned our
text into, a handsome 200-page illustrated book of which Dennis,
my co-editor, and I can be proud. I didn''t even come close to any
of the publication deadlines that were set by Mary. Yet the
deadline that counted was met and the attendees received their
books.
But I digress. You''re skeptical that I talked with Ben Franklin?
Well, he and three beautifully costumed Mummer music makers
welcomed the celebrants into the Crystal Tea Room of the
Wannamaker Building. After the 800 banqueteers were inside,
Ben and the Mummers led us members of the Centennial
Committee through the cheering crowd to the stage. It was the
closest I''ll ever come to experiencing what it must be like to be
honored in a ticker tape parade. Ben then gave a little speech
and left us to our own devices. I must say that Ben has not aged
much over the centuries, although he did seem a bit more rotund
than in the portraits I''d seen. I also suspect that he dyes his hair,
it being of a somewhat reddish tinge.
Unfortunately, I didn''t have enough time to ask Ben about his
kite flying. I don''t know about you, but I''ve always had this
vision of Ben standing out in the midst of a thunderstorm flying
this silly kite and risking his life in the process. This vision is
certainly promoted by the portrait reproduced in the American
Heritage article. The portrait, by Benjamin West (1816), shows
Franklin standing boldly out in the storm holding his kite string
with key attached. I''m reasonably sure that the cherubs in the
background represent a bit of artistic license. My suspicions
prompted a more thorough search for details of Franklin''s actual
actions back in June of 1752. What follows is a distillation of
material obtained from Web sites such as ushistory.org and
boltlighningprotection.com, as well as my trusty 1962 edition of
The World Book Encyclopedia.
It seems that my friend Ben was not as foolhardy as the portrait
would suggest. He apparently did not stand out in a raging
thunderstorm but was much more circumspect and flew his kite
from inside a shed. He did attach some sort of metal spike or
wire to the end of the kite and tied the key down close to where
he held the string. But he also seems to have knotted a silk cord
to the hemp string attached to the kite. The silk string or cord
was not a good conductor of electricity so in principle this
protected him from being electrocuted. The key was located just
above the knot. By staying in the shed under cover, the silk was
kept dry to ensure that it didn''t get wet and become a conductor.
(Remember not to touch a light switch with wet hands for much
the same reason.)
Franklin also was sensible enough to recognize the danger and
appears to have flown his kite near clouds of an approaching
storm before the lightning had begun to show up. Thus, he did
not actually initiate a lightning bolt as we know it. Instead he
essentially drew some of the charge out of the cloud onto his kite
and onto the key he had attached to the string. He determined
that the key was charged up by drawing a spark to his knuckle
when he placed the knuckle near the key.
Back in 1752, communications were slow and Franklin didn''t
know that, just a month or so before, some French "electricians"
had beaten him to the punch in showing that lightning and
electricity were equivalent. They had put a metal spike on a tall
building and had drawn sparks from a thundercloud, as Franklin
had suggested and later used to form a lightning rod that
protected his own house from damage when struck by lightning.
Today, we know that there are various forms of lightning. The
one type that worries me most is the cloud- to-ground form. The
most common cloud-to-ground lightning involves several steps.
First, the cloud gets charged up by some process not totally
understood. Typically, negative charges build up on the bottom
of the cloud. Then these negative charges form what is known as
a "stepped leader" that branches out from the cloud looking for
an easy path to the ground. As this negatively charged leader
approaches the ground another leader is induced to come up from
the ground and the two join together.
This joining clears the way for a return stroke passing from the
ground to the cloud. During all this, the air along the path gets
heated up really hot and the shock waves set up by the hot air
expanding gives us the thunder. With the channel now open what
is known as a "dart leader" can propagate down the hot channel
and spur another return leader. All this happens in much less
than a second. In fact, it seems now that several leaders and
return strokes can make up what seems to be a single lightning
bolt to our eyes. Lightning is still a subject of intensive study.
Some of you might question whether my Ben Franklin was for
real. Well, I''m no dummy - I broached that very question to him.
Some years ago, on a visit to the Corning Glass museum in
Corning, New York, who should be there but "Ben Franklin"!
My colleague, Al, was with me at the time and took issue with
Ben on a point relating to batteries. Al was a vice president of a
battery company and an authority in the field. In Philadelphia, I
asked Ben if he had ever been in the Corning area. Ben replied
that he had heard that there was an imposter up there in Corning
and, while he wasn''t happy with anyone impersonating him, he
understood that the imposter did a fairly good job.
Consulting my World Book Encyclopedia, I learned that this
relatively magnanimous response was typical Franklin. Back in
the 1700s when he was in his prime, Franklin didn''t patent his
inventions. Rather, he preferred to let them be used for the
improvement of the lives of everyone. In spite of all his
achievements in science, publishing and statesmanship, this
founding father of our country began his will simply "I,
Benjamin Franklin, printer…."
To me, the evidence is certainly stronger that I was chatting with
the real Ben Franklin than it is that Elvis still lives. Just the other
day I heard a news report to the effect that someone had new
proof that Elvis is indeed still with us. I certainly believe that, if
Elvis survives, good old Ben would have found the secret to
extreme longevity long ago.
Allen F. Bortrum
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