The Mysterious Life of Ice

by Ned Rozell

Then, the unthinkable happens. Instead of sinking in its birth liquid, as would most any other solid, the iceberg pops to the surface like a breaching whale.

Ice floats, and it shouldn’t. In short, ice is baffling, enough that scientists have studied it for decades without tiring of its mysteries.

One of those scientists compared water molecules nearing the freezing point to a group of soldiers milling about on a parade ground, waiting for an officer’s review. At a magic moment when the temperature drops to 32 degrees Fahrenheit, the soldier molecules stand in orderly rows, stiff-arming one another. The stiff-arms of hydrogen bonds limit the contraction that happens within almost every other solid when it freezes, making ice less dense than water.

Ice allows skaters to glide at 20 below, when the cold, hard surface should be about as slippery as concrete. A group of scientists curious about ice recently used an atomic microscope and find a thin, wet, quasi-fluid layer of water on the surface of an ice crystal. No matter how far the Berkeley team lowered the temperature of the ice, the layer remained. That persistent film of water, they argue, is the lubricant that makes ice slippery.

Alaska’s great reservoir of ice is returning to its wetter self in a hurry. Almost every glacier here is shrinking—fast. The amount of meltwater from Alaska’s glaciers that have emptied into the ocean since the 1950s would cover the state of Texas

with 15 feet of water. Since that time Alaska's melting glaciers have raised the global sea level by a quarter inch.

Computer models predict that sea ice will no longer abut the northern coast of Alaska in the next century, instead withering to a smallish disc surrounding the North Pole. More mysterious are the massive ice reserves in Antarctica, which may be growing as northern ice shrinks.

Earth has cycled through epochs of great ice sheets that locked up much of the world’s water and warmer periods that have drowned land bridges with salt water. Change seems the only real constant, but there is another: Ice, one of nature’s most mysterious compounds.

Alaska’s great reservoir of ice is returning to its wetter self in a hurry. Almost every glacier here is shrinking—fast. The amount of meltwater from Alaska’s glaciers that have emptied into the ocean since the 1950s would cover the state of Texas with 15 feet of water. Since that time Alaska's melting glaciers have raised the global sea level by a quarter inch.

Computer models predict that sea ice will no longer abut the northern coast of Alaska in the next century, instead withering to a smallish disc surrounding the North Pole. More mysterious are the massive ice reserves in Antarctica, which may be growing as northern ice shrinks.

Earth has cycled through epochs of great ice sheets that locked up much of the world’s water and warmer periods that have drowned land bridges with salt water. Change seems the only real constant, but there is another: Ice, one of nature’s most mysterious compounds.