A Drop of Water
Nature Bulletin No. 407-A Fe4braury 20, 1971
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
A DROP OF WATER
You may be acquainted with Smokey, the dressed-up bear who begs us
to prevent forest fires, but did you ever hear of Willie Willing Water?
He comes to us, first, as a raindrop from the sky but his ancestors came
from the ocean. Until recently, most people believed that he arrived as a
"teardrop" shape which has been imitated in automobiles, airplanes and
other objects streamlined for lessening resistance to their swift travel
through the air. High-speed pictures have revealed that, as he falls, this
is flattened into a saucer-like disk.
As a matter of fact, gravity is a dominant force through most of Willie's
life. It brings him down from the sky where he was born. Upon landing,
unless he falls into a pond or lake, he will continue downward as long
as there i9 an opening through which he can move. Sometimes there is
none, so he must travel over a sloping surface.
Generally, Willie can run faster on a steep slope than he can on a gentle
one. Of course, if the slope is covered with trees, shrubs, thick grass or
even weeds, that slows him up. On bare ground, he and his brothers
push aside or carry along any crumbs of soil in their path and, in their
hurry to get back to the ocean, carve a channel which eventually may
become an ugly gully.
Underground, too, the gradients (or slopes) of the openings or channels
available to him are important, and his rate of progress also depends a
lot upon the obstacles he meets in soil or rock materials. Unless he
happens to find a subterranean stream, his travel is apt to be very, very
Willie, like a small boy with candy, absorbs some of most anything with
which he comes in contact. As he falls to earth he may pick up fine
particles of dust carried by winds; or such gases as sulfur dioxide and
carbon dioxide in the fog and smoke that hang above so many of our
cities. If he travels over the surface of the ground, or falls into a
polluted stream or lake, he picks up other impurities. If he travels
underground, he picks up minerals.
All common minerals are soluble in water to some extent but some --
like salt, potash, gypsum and limestone -- are far more soluble than
most. Having absorbed them, Willie is like a small boy in another
respect: there may come a time when he "upchucks " and leaves behind
some of these minerals. We see deposits of them around springs, or in
the form of stalactites and stalagmites in caves. We also see them in
such places as the alkali deserts of the Southwest and around the Great
Salt Lake in Utah -- minerals deposited by the evaporation of water.
The sun is another dominant force in Willie's life. If it can get at him, he
is evaporated and pulled up into the sky to form clouds. Below ground,
he may be pulled to the surface by capillary -- or blotting -- action and
then evaporated; or he may be sucked up by plant roots to the leaves
and returned to the atmosphere as vapor -- moisture so fine we cannot
see it. Either way, he leaves behind any minerals and impurities he may
If he does manage to reach a stream and return to Old Father Ocean,
sooner or later Willie is apt to be evaporated again, wafted away by
wind, and eventually returned to earth where he has another series of
adventures. That is known as the "water cycle" and it makes this
country a good place to live in.
Wee Willie Willing Water: what would we do without him?
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Update: June 2012