Pure water, sitting in a perfectly smooth, sterile beaker, can actually stay liquid down to -40 degrees. That’s the same temperature on both scales, by the way, which is the universe’s way of saying “this is getting weird.” We call this supercooling, and it’s nature’s version of a teenager refusing to go to bed.
You can shake that bottled water from your fridge all you want. It’s just biding its time, waiting for the perfect moment to slam into a slushy solid. It’s like a polite guest who suddenly decides to throw a chair through a window.
Why Your Ice Cubes Are Lying to You
Tap water freezes at a slightly lower temperature than 32°F because of all the dissolved minerals and chlorine. It’s like the water has a tiny, grumpy entourage that delays the party. Meanwhile, salt water from the ocean needs to get down to about 28.4°F before it gives up—and even then, only the fresh water freezes out, leaving the salt behind.
This is why icebergs are made of drinkable fresh water. The ocean basically sweats out ice cubes for your future cocktail. Show off that fact at your next party. You’ll be a hero, or at least the weirdest person there.
