Sunday, July 18, 2010

The Six Million Dollar Turkey?

A few days ago, Jacqueline and I were walking along a road in Vineyard Haven, on Martha’s Vineyard, Massachusetts. We had heard that wild turkeys roamed around, so we were not surprised to see one. It was about 50 feet away, under a tree.

To appreciate what the turkey did next, you need to know the 1970s television show The Six Million Dollar Man. In it, a man is retrofitted with “bionic” technology that gives him superhuman abilities. When he does a standing jump, he starts with a normal jumping motion, yet he keeps going up. It looks wrong because it violates what we know humans can do.

Since Jacqueline and I thought turkeys don’t fly, we had a Six Million Dollar Turkey moment when the one we saw launched itself straight up to a branch fifteen feet above, wings flapping. It’s a testament to the power of mental models that our initial thought was, “How did the turkey do that?

And only after, “I guess turkeys can fly.”

Subsequent research showed that wild turkeys can fly, not particularly far or high, but they can fly. The idea that turkeys are flightless comes from domesticated turkeys, the larger versions of which cannot fly.

Sunday, July 11, 2010

The Wisdom of Water Towers

Why do water towers exist? You pump water up into the tower, only to have it come back down before it goes to its destination. Why not save the up-down circuit and just pump straight to the destination?

This question arose a week ago on my family’s annual summer visit to a small town amid the Illinois cornfields. Out there all the towns have water towers. Here is why.

Towns have pumping stations that can pump water directly to homes and businesses. However, demand for water is not constant. Overnight water use is low, but demand peaks in the morning when people are showering and starting their days. Building a pumping station to handle the peak demand is inefficient because the pumping station would only use a small fraction of its capacity most of the day.

Enter the water tower. It allows a town to build a pumping station that handles only the average daily demand, using the water tower as a cache. When demand is low, such as overnight, the pumping station fills the tower. When peak demand occurs in the morning, the tower releases water. Gravity acts as a virtual pump, allowing the tower to augment the actual pumping station. (The water tower can also be a temporary substitute for the pumping station in case of maintenance or a power failure.)

Water towers are prominent features of midwest towns because the geography is flat. The only way to elevate the water to the necessary height is to use a tower. In more varied terrain, the equivalent of a water tower is a big tank on a hill. In an urban downtown with skyscrapers, tanks may be on the roofs.

Whatever the location, an elevated cache of water is a simple, effective idea.