Why are there spikes growing out of my ice tray?

Question

This is sooo weird. As is my habit, I filled my ice trays with cold tap water and let them settle on the counter for 15 minutes or so. Then I put them in the freezer. A few hours later I opened the freezer and found that the ice had these nail-like projections. The longest was maybe 3 inches long. They weren't touching anything. What the heck happened? Notice the baby dude in the first picture? WTF?

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score 41 · Accepted Answer · edited Sep 24 '13 at 04:17

41

They're often called ice spikes. Ten years ago these things were pretty mysterious, but now Wikipedia even has a video of them growing out of ice cube trays in a freezer.

Basically, the ice surface freezes first, which slightly pressurizes the water underneath. That water breaks through the crust, and continues to flow, and freeze to equalize pressure within the cooling cube. Temperature conditions have to be just right for it to happen, so you don't see them all the time.

edited Sep 24 '13 at 04:17

Cascabel

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answered Sep 23 '13 at 13:59

Wayfaring Stranger

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So I guess the big question now is, "Are they safe to drink?" – Jolenealaska Sep 24 '13 at 14:48
@Jolenealaska Should be. The contaminants in freezing water tend to get concentrated into the last bit that freezes, via the process of freezing point depression. Since the spike can't be the last bit to freeze, it should be reasonably pure water. – Wayfaring Stranger Sep 24 '13 at 17:53
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The question was actually intended to be a small joke. – Jolenealaska Sep 25 '13 at 04:03
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Well, you could poke an eye out if you're not careful with em. – Wayfaring Stranger Sep 25 '13 at 05:24

Why are there spikes growing out of my ice tray?

1 Answers1