Dear Science,

I've got a question for ya: My boyfriend's roommate had one of those bottles of premixed cocktails stored in the freezer. For months, it languished there in its liquid state. This evening, I decided to help myself to a glass. I took the bottle out, poured some, and closed it. Almost instantly, the contents began to freeze AT ROOM TEMPERATURE. Okay, Science, how is this possible?

A Confused Drunk

Science is utterly thrilled to answer this question, combining his true loves of chemistry, phase changes, and tricks with common household appliances. Water, you must know, is totally amazing—quite possibly the greatest molecule of all time. And, as awe-inspiring as water is, it sometimes needs a place to start freezing.

The premixed cocktail you poured is mostly water. The alcohol, sugar, salt, and flavorings are just pushing around the poor water molecules, getting in the way. Pure water would be glad to freeze at 32 degrees Fahrenheit, but we're going to say 0 degrees Celsius because science seriously hates imperial measurements for temperature—32 to 212 degrees Fahrenheit for water? Boo! Zero to 100, please.

Back to the water in your premixed drink: All of the other stuff gets in the way of the water, dropping the temperature at which it'll freeze below 0 centigrade. But your freezer, at about minus 20 degrees Celsius (okay, okay—about 0 degrees Fahrenheit) is cold enough to freeze even premixed cocktails.

So the liquid, right before you poured your drink, was cold enough to freeze. Why didn't it? The water needed an example of something solid, some place to start freezing on, before it could even conceive of the task; this little starting point is called a nucleation. It can be a scratch on the inside of the bottle, a speck of dust, a little grain of sand, or whatever.

When you opened the bottle—a bottle probably too smooth inside to have good nucleation sites—to pour yourself a drink, a little speck of dust probably drifted in. When it hit the liquid, the water in there, superchilled well below its freezing point, said, "Hey! This solid stuff seems like a nifty idea! Let's try." So, the water stretched out, forming a little ice crystal around the speck of dust. The neighboring water saw this and quickly jumped in on the game. Within a blink of an eye, the whole bottle's worth was frozen solid. Wild! The same basic idea is going on when your mug of microwaved water froths into a mess when you dip in your teabag—it's superheated well above the boiling point and just needed a good nucleation site for the bubbles of water vapor to start forming.

Exemplarily Yours,

Science

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