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One can imagine
people in prehistoric times watching the surface of a puddle during
an evening rainstorm. Drops of water would create splashes,
and sudden flashes of lightning would make the splashes
visible. However, there was no dependable way of looking at
drops and splashes until little over a century ago.
The first systematic study of splashes was
carried out in the early 1890's, by the English physics professor
A. M. Worthington. In 1894, he gave a lecture entitled
"The Splash of a Drop and Allied Phenomena," which
featured drawings of water and mercury
splashes. In the lecture, Worthington described various stages in the life of a mercury drop falling against
glass. He also studied splashes of drops of water mixed with milk. He explained how he
was able to repeatedly create drops of definite sizes, release them
from definite heights, and use lightning-like electrical
discharges to freeze each falling drop long enough to be seen.
Worthington
initially used sketches instead of film to record his
observations. When asked why he didn't start out with
photographs, he
claimed that photographic plates were not sensitive enough to
respond to the very brief exposure times needed to freeze a drop in time, without blur.
Later, with the
help of contemporaries Lord Rayleigh and industrial scientist
C.V. Boys, Worthington used powerful sparks from Leyden jars to
create the necessary brief exposure times. Finally,
Worthington was able to take high-speed photographs of his
splashes.
In 1908,
Worthington published a book entitled, A Study of Splashes.1
There were 199 sketches of drops and splashes in the book. For the first time, the public could see the different stages of
a splash, and could question why splashes evolve in
the ways they do.
Although
Worthington's work in studying splashes was the most
exhaustive of any such work both before and after him, the person
whose name is generally associated with photographs of splashes
is Harold Edgerton. Edgerton, a professor at MIT for 58 years,
made many important developments in the fields of high-speed and
underwater photography and sonar. He probably did more than
anyone to popularize high-speed photography. Many of his
photographs have appeared in National Geographic magazine as
well as several books. Some of his most well-known subjects
include an apple being shot with a bullet, a playing card being
split with a bullet, footballs and golf balls being struck, and
athletes in motion. But splashes of milk drops are perhaps the
most familiar of his images. A collection of his photographs
of drops and splashes as well as many other images is found on
the compact disc, Exploring the Art and Science of Stopping Time,2
published by the MIT Press.
More than a century
has passed since Worthington took his first splash photographs, but we never tire of seeing these beautiful, elegant structures of
nature.
1.
Worthington,
A. M. A Study of Splashes. New York; MacMillan,
1963.
2. Exploring
the Art and Science of Stopping Time, Cambridge, MIT Press,
1999.
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