I made some ice recently and was surprised to see “stalagmites” that had grown from the surface of the cubes.
I’d never seen/heard of such a thing, but online I found that it is not uncommon.
The short explanation is this: as the ice freezes fast under supercooled conditions, the surface can get covered except for a small hole. Water expands when it freezes. As freezing continues, the expanding ice under the surface forces the remaining water up through the hole and it freezes around the edge forming a hollow spike. Eventually, the whole thing freezes and the spike is left.
Why have I never seen this phenomenon before?
Pure distilled water, on the other hand, more regularly yielded ice spikes, though still unpredictably, Libbrecht says.
We recently improved our home water filtration, and the more pure the water, the more likely spikes will form.
Anyone else ever see these??
I get those on my hot tub cover during the winter months. Some have been over 2 inches long.
I’ve seen nubs in our cubs but ISTR the Science Channel program “Outrageous Acts of Science” showing really extreme spikes. Might have been some other show under Discovery’s umbrella.
I’ve started getting these on my ice cubes since we got a new refrigerator a couple of weeks ago. I’m using filtered but not distilled water. I never saw them with my old refrigerator using the same water source; maybe the new fridge is colder, or has different air circulation in the freezer. They are pretty interesting.
I’ve seen it frequently in our freezer. I could’ve sworn that Jearl Walker’s Flying Circus of Physics had a section devoted to the phenomenon, but I can’t find it.
When I posted the OP, (2 years ago, almost) I showed them to my gf and explained the phenomenon. She’s not very science oriented, but she has told friends about this and why it occurs. It has become her one science thing she really knows.