Spikecicles?

Factual Questions
1

Hey SDMB’ers

I’ve read all the articles on ice, warm water freezing faster than cold water, etc. and haven’t found any articles relating to my latest observations.

Spikes on top of ice-cubes. I am using a standard ice tray, purified water (via reverse osmosis), and a defrost free freezer. The spikes appear on one to three cubes and are about 1/4 to 3/4 of an inch tall and an 1/8th of an inch thick.

I was able to get some pictures, but can’t post them. I’m working on getting them up on a web site. Maybe someone could respond and I’ll send them to that person and that person could post them somewhere. Just to make things complicated. :slight_smile:

One wild theory is that it is some sort of reverse sublimation during the defrost cycle of the freezer. Another wild ass guess is that the purified water is compressed in the middle, then breaks through the ice and instantly freezes due to a drop in pressure. What do you guys think? (in this case guys means girls too)

Thanks in advance for your help,
-Andrew Kay

2

A few questions:

(1) Do these spike appear fairly sharp and conical, like stalagmites in a cave or are they more like a buckling that appears distributed across the top of the cube? (perhaps that was what you meant by 1/8 inch thick? girth?)

(2) Are they fairly smooth and regular or are they jagged and ‘fuzzy’ like a crystaline growth?

(3) Is this a one-time phenomenon or do you see these spikes regularly on most batches of ice? Also, do the spikes tend to appear in the same general location in the tray?

3

http://boards.straightdope.com/sdmb/showthread.php?threadid=27434

4

Hey All,

Well it looks like I’m not the only one this happens to. (deep sigh of relief, freezer is not haunted) It also looks like that there was already a thread on this, and the thread has comments that support the first theory that it has something to do with the defrost cycle, warm air, and reverse sublimation.

I agree with ZenBeam on the previous thread. Spurting water suddenly freezing would have more water near the end of the icicle than at the base. All my icicle’s are thicker at the base than at the top.

I will freeze a tray of ice cubes in an envelope so no air currents can affect the ice and see what happens. I will also freeze a tray and check it every 10 minutes to see what happens.

You can look at links of the post above to see pictures.

To answer JoeyBlades Questions

  1. The spikes are fairly sharp and conical. 1/8 in diameter, thicker at the bottom, thinner at the top.
  2. Smooth.
  3. It happens 90% of the time.

Thanks Sigene
-SandWriter

5

I seriously doubt the reverse sublimation theory. This would not explain the shapes. Reverse sublimation, if it’s even possible with water vapor, would tend to be more evenly distributed so that even if you did detect peaks, they would tend to be humps - not cones, rods, or wedges.

Here’s my working theory, and it’s based on an observation I saw in a friends’ freezer a couple of years back:

The defrost cycle (if not optimized) continually creates a pattern of thawing, condensation, and refreezing. Depending on conditions, this can create stalatites (icicles) and/or stalagmites (spikecicles). Either way, these formations will have ample opportunity to grow. They may tend to congregate in areas of higher water vapor (i.e. over the top of an ice tray).

If they grow from the top down, eventually, during one of the defrost cycles they may grow heavy enough to lose their grip and fall. If they land on an ice cube, the small amount of liquid water on the surface can instantly freeze - sticking the icicle in a mostly upright position (similar principle to sticking a cold ice cube to your tongue). In fact, I have seen such tiny icicles growing over the ice trays in my aforementioned friend’s freezer. BTW, once the icicle falls, depending on a lot of different factors, it can reflow into a number of different shapes or develop a slant, etc… Another factor in support of this theory are the wedge-like formations in some of the pictures. These look remarkably like fallen “ice curtains”. The only problem that I see with this theory is that you would expect to find a few fallen icicles laying on their sides and some still hanging from above the ice trays. These phenomena have not been described (which doesn’t necessarily mean it’s not occuring).

Alternatively, if the defrost cycle is just slightly warmer, the condensation might fall and the small water droplets would refreeze fairly instantly forming stalagmite like structures. These might tend to be mostly vertical, but defrost cycles and air currents from blowers might make them tend to lean once they reach a certain height. Come to think of it, a leaning structure, under the right conditions might take on the shape of the wedges depicted. One way to check out this theory would be to look for smooth bumps directly above the ice trays. This would be indicative of condensation droplets freezing and thawing.

I’m sure there are a lot of holes in this theory, but I haven’t seen anything in either thread to necessarily contradict it…

6

Is the following possible? As water freezes it expands, as it expands it should start to form a kind of ‘bubble’ on top due to survace tension. (like when you pour water over the top of a glass it domes. This happens with your ice cube trays, but once it gets to be a certain height it will actually touch the tray above it and freeze like that. A picture I am trying to explain with touching is when you touch your finger to the top of a glass of water and it kinda sucks up a column to your finger. I used to know all of these neat chemistry terms, but now I have changed my career focus to a computer one, so please excuse the simple descriptions.