Thursday, September 18, 2014

Pushing Water Uphill

Like much of Seattle, our entire outdoor space is on a slope. We've positioned our cast iron water pump near the top, in the sand pit, which means it doesn't take much effort to get a nice river flowing.

It's one of the main things we do out there, year-round, with the exception of the month or so when there is a genuine risk of pipes freezing. When they're young, they're often just pumping and watching, but as they get older and more experienced it becomes about managing the flow through trail-and-error engineering.

We learn a lot by doing this, of course, and one of the foundational facts every child discovers is that water doesn't easily flow uphill. We know this because we've tried to make it happen.

Yesterday, we got a nice long river flowing that the kids terminated in a single, deep hole at the bottom of the sand pit. After playing with the mud for awhile, some of the guys decided to create an exit stream that ran toward the base of the concrete slide, a direction that is slightly uphill, but not so much that you would notice it without a close study. They dug hard, but the water didn't cooperate. Someone had the idea to incorporate a length of pipe only to discover that the great truth about gravity still held true. 

That is, until a friend figured out that he could dip one end into the deeper water, then lift it in a sort of scooping motion, collecting a bit of water in the pipe, which then, with the pipe tipped, ran "uphill" to where his buddies dug. He did it over and over, creating a fairly steady trickle for them to manage, which they did until he was ready to quit. Getting water uphill can be done, but it uses more energy.

Later, the play moved up near the pump, where the center of attention was a section of vacuum cleaner hose. They were attempting to attach it to the pump's spout in order to get water flowing through it as it lay in a length of gutter. It was flowing away, when one of the guys picked up the downhill end, lifting it higher than the pump's spout. The flow stopped. He looked into the hose to check things out, lowering it just a little so that it was now lower than the spout, but still higher than the center section of the hose. Suddenly, conditions just right, the water began to spurt out. 

"It came up the hose!" he laughed, redirecting the flow away from his face. "Keep pumping!"

And his friend answered, "It came up the pump, then down the hose, then up the hose." They knew what they had done. It took a lot of fiddling then, but they discovered that by raising and lowering the open end, they could use that flexible hose to direct the water to anywhere within reach, a game for the rest of the afternoon.

When I worked for the chamber of commerce one of my boss's favorite expressions was, "It's like trying to push water uphill," meaning, of course, that we were trying to do something that was next to impossible. It usually meant we should just give it up, perhaps a lesson for when efficiency is the goal, but these lessons are not about efficiency. They are about science, and when it comes to science efficiency is the enemy of truth.

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