We usually undervalue the commonplace. Clouds are less appreciated than rainbows, while rainbows are deservedly less exalted than the super-vivid circumzenithal arc, which dramatically appears overhead a few times a year like a spectral smiley-face. Yet it’s hard not to appreciate water, despite it being the most common compound in the cosmos.
Usually it manifests as ice or gas. For example, the rings of Saturn are countless ice chunks, and comet tails are mostly water vapor. It’s all around us, yet we nonetheless often regard it as beautiful.
Here on Earth, it mostly assumes its rarest-by-far form: liquid. Gaseous water is totally invisible. Clouds are not vapor, but countless tiny droplets. And that two-inch transparent gap between a teapot’s spout and the white “steam” – that’s the actual vapor. The white stuff popularly called “steam” really isn’t. Steam is invisible. The white cloud forming near the teapot spout is merely where tiny drops are condensing. The water phase only exists in an extremely narrow temperature range, and even that is not enough; the H2O must also sit under pressure, supplied on this planet by the atmosphere’s weight. Only then do you get its transparent liquidy magic.
Next time you hold a glass of water, consider: Two-thirds of its contents are pure hydrogen atoms, which also compose most of the cosmos. Hydrogen, normally incapable of holding our attention for more than a few mandatory moments in Chemistry lab, has managed to make us wide-eyed only a few times in our lives. When the Hindenburg and later the Challenger exploded, the fascinating and horrible spectacles were demonstrations of the simplest possible chemistry. Here was hydrogen releasing itself from a human cage to find its way to its favorite companion: oxygen. Their eternal offspring is water, so that during the explosions, the white billowing “smoke” surrounding both dying airships was simply…cloud. Sunlight is a direct manifestation of hydrogen’s creativity, and yet we rarely think of it either.
That drinking glass’s other component, oxygen, is so much heavier than hydrogen – atom by atom, oxygen is 16 times more massive – that even though there are twice as many hydrogen as oxygen atoms in water, seven-eighths of the water’s weight are oxygen. Since your body is mostly water, two-thirds of your own weight are pure oxygen too.
Around here, unlike in Nevada, nature’s canvases are dominated by watery brushstrokes. A curling wisp of cloud drifts above, its arabesque patterns mutating like the letters of an alien language. A line of blue-white icicles hangs menacingly from a roof eave. Still, it’s the flowing liquid of our still-unfrozen brooks that roils in water’s endless liquid designs.
Water’s strangest and least-appreciated characteristic is this: The two hydrogen atoms chemically bonded to one oxygen atom that comprise water are not linked in a straight line (180 degrees) but at an angle of 105 degrees. This fact alone has made life on Earth possible, and perhaps on endless other worlds as well.
The angle of 105 degrees gives the water molecule a kind of polarity where the oxygen portion has a more negative and the hydrogen portion a more positive attraction. This results in water molecules aligning themselves. The oxygen of one bonds to the hydrogen of the next in a network of weak connections. So instead of being a loose mixture of individual molecules, water is a latticework that behaves like a much bigger structure.
This little feature has tremendous significance. Without such unusual electrical bonding, water would be like all the other molecules of its size and weight: a gas at room temperature. This odd hydrogen bonding is why your veins and brains are filled with fluid instead of vapor.
It’s critical, almost magical – and worth a moment of our notice.
Want to know more? To read Bob Berman’s previous “Night Sky” columns, visit our Almanac Weekly website at www.HudsonValleyAlmanacWeekly.com.