In 2013, The Nature Museum is offering an interesting and diverse lecture series on water. Lots of thoughts come to mind, but none is more important than the fact that we humans are 70% water (by weight). Water is the primary physiological challenge for any terrestrial organism. Plant or animal, we are all at risk of drying out.  

Back here in the well-watered East, we wonder what the fuss is about. But in the American West, it's all about water. They are in a major, long-term drought and the stakes are high. As a kid growing up in western Montana, I knew that the local "ditch walker" was the most important guy in town. He settled disputes between irrigation ditch users, who constantly cheated on one another by using more water than their "water rights" allowed. If you wanted to farm, or even ranch, it wasn't about land; it was about those all-important water rights. They were deeded, and they were gold.

This century may well be remembered as the century of water. The highly volatile struggle in the Middle East is as much about water as it is about land. (Read anything by Tom Friedman these days to learn more.) Australia is drying up. There is an historic line there that delineates where water is somewhat predictable, and where it is not. Almost no one lives north and west of that line. Because of profligate and unwise water use, many parts of the world are now turning into vegetative deserts of salt-laden soil.  

Here in the U.S., besides the drought in the West, we are rapidly depleting the ice-age Ogallala aquifer that provides water for the Midwest, Oklahoma, and west Texas. The Colorado River is dry by the time it gets to its famous, but now historic, estuary in Mexico. Because of greed, the deluded notion of energy independence, and political shortsightedness, we may harm groundwater above the gas-bearing shales of several Mid-Atlantic States. Groundwater is poorly understood, slowly recharged, and nearly impossible to cleanse. What do you want in your water well?

What makes water life-giving is its very odd behavior. It's a simple, tiny molecule that should be a gas at room (or body) temperature. It's not a gas because its two hydrogen and one oxygen atoms make the molecule "sticky." So water molecules stick to one another, via weak bonds, forming a liquid at the temperatures we care about. As a result, we can have water droplets in a gentle rain, a pond full of spring peepers, and blood in our veins.

Water boils at a ridiculously high temperature for a molecule its size because we have to break all those bonds. It does, however, slowly evaporate at lower temperatures. We benefit from that because we can cool our bodies as the sweat that appears on our skin is torn into individual molecules that leave as gas. Your elevated skin temperature provided the energy to make that happen and so your heat is dissipated.