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The line between the float and the ball tightened, but instead of be-
ing jerked o¤ the hole, the ball lifted up a quarter of an inch and then
snapped back down. As the water flowed into the reservoir, the ball
continued to bounce up and down, letting a little bit of water out with
each bounce. All of a sudden, memories of my UCLA physics classes
came back to me, and the problem became clear. What I had here was
a perfect illustration of Bernoulli's principle, where high velocity cre-
ates low pressure—the same principle that allows airplanes to fly. When
the water rushed out below the ball, it created low pressure, which
promptly pulled the ball back down. As soon as I realized my idea would
never work—unless, that is, I could repeal the laws of physics—I junked
it and began work on another.
My new plan was to create an automatic siphon. The beauty of this
design was that it had no moving parts— other than a supply of water.
I built a small-scale model out of an old bucket. Using heat, I bent a
piece of PVC pipe into a U shape, with one side of the U much longer
than the other. Drilling a hole near the top of the bucket's wall, I in-
stalled and sealed the U-shaped pipe so that the short arm was just o¤
the bottom of the bucket and the long arm extended well below the
bucket on the outside. I started filling the bucket, and as it filled, the
short end of the pipe also filled. As soon as the water reached the top
of the pipe, it started spilling over into the long side. This rapidly falling
water carried the air out with it, until quickly the entire pipe was full
of water. At that point the pipe became a siphon and the bucket emp-
tied with a rush. Once it was empty, the siphon stopped and the process
started over again. It was so simple!
Now came the scary part: scaling it up in size for the six-hundred-
gallon tide pool exhibit. This was going to cost the aquarium a lot of
bucks, and I was still not one hundred percent sure it was going to work.
First, a two-hundred-gallon fiberglass reservoir was mounted on a steel
platform bolted to the wall fifteen feet above the tide pool. Then a
twenty-foot-long piece of six-inch-diameter PVC pipe was heated in
a giant oven and curved into a big, lopsided U shape. It was installed
through the side of the reservoir as in my mock-up, with the end of the
long arm just penetrating the water surface in the tide pool below.
I was very nervous when the pump was turned on to begin filling
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