I've always wondered how come liquor doesn't freeze in the freezer, how come?
- Drunk and confused in Santee
I'm only eight, but I've noticed that ice cubes have little peaks in them. They're not flat like a hockey rink.
-- Bobby, El Cajon
How does the crisper in my refrigerator work? Magic?
-- Jay, out there
This week at the Alice household was our semi-annual Get Rid of the Fuzzy Stuff festival, which involves Grandma and various conscripts crawling through the fridge, sorting the edible from the throwable. Pa Alice always volunteers to do the freezer and takes a fifth of tequila with him. It's probably never occurred to him that tequila will freeze. Any alcohol will, but not at the temps generated by your average Kenmore side-by-side with in-door water dispenser.
Booze, aluminum, neon, practically anything you have hanging around your house will freeze if the temp gets low enough. Basically, reducing the temperature slows molecular motion in the substance, and depending on the structure and binding forces of the molecules, you'll eventually get some kind of looser or tighter bond between them. Water is a pushover. It's a simple substance made of hydrogen and oxygen atoms all sailing around at speeds determined in part by their temperature, slower if they're cold. At some temp below 32 degrees F. the molecular motion is slow enough to allow the attractive forces between one molecule's positively charged hydrogen atom to catch the eye of another molecule's negatively charged oxygen atoms and they stick together in the form of a predictable latticework solid. Once most or all of the atoms are stuck together, the unmated electrons clinging cozily to the oxygen, you have ice.
You might get peaky ice in an ice tray because water is one of only a few substances that can expand in volume when it freezes. The lattice ice structure created by the hydrogen bonds has slightly more space in it than do the same number of water molecules on the loose. Since water in an ice tray will freeze from the edge to the center, the "extra" ice commonly forms a lump there.
But what about Pa's tequila? It will freeze at some temperature higher than pure ethanol (the drinking form of alcohol). Ethanol will freeze -202 degrees F. Alcohol resists what water falls for so easily in part because of the carbon content of alcohol. There is an oxygen-hydrogen component in alcohols, but they also have various forms of carbon molecules, and O and H have little or no interest in sticking to them. Alcohol is more volatile and contains more energy than water, making it hard to slow it down and get its attention long enough to get it to solidify. Alcohol doesn't have many built-in atomic attractants like water's ionized hydrogen and oxygen.
Grandma's least favorite clean-up is the vegetable crisper drawers. The elves have found them to be the perfect place to curl up for an afternoon nap when it's just too hot outside. You might think of your magic crisper in these terms. Once upon a time, it was too cold outside, so man built a house. Then it was too hot in the house to store his food, so he invented the refrigerator. Then he realized the air in the refrigerator was too dry to store his green vegetables, so he invented the crisper. I'm sure you've noticed that bread, cheese, and unprotected veggies turn crusty or limp if left on a regular fridge shelf. Crisper drawers protect foods from the constantly circulating dry, cold air in the fridge. Crispers aren't much magic, but because they're slightly damp, they're a particularly good place to find those fuzzy to near liquefied throw-outables.