The light in the evening with the time change has given a perception of a longer day. The sun peered in my bedroom window into the dinner hour. I was contemplating during my bedroom into a dining room.
The temperature outside, though, is cold, especially since the sun went down. The sun disappeared behind the mountain when I was in the gym, and my light hooded jacket that I wore into the gym did not do the trick. The freezing had begun.
After getting out of my car, I once again looked at the unusual phenomenon that had perplexed me since yesterday.
Every second Tuesday in my part of the world, the city collects the garbage. (Yes, it is only every two weeks!) Since I leave early and since I have very curious dogs in my neighbourhood, I leave the garbage in the garbage can. Both of the cans acquired a lot of water during the melting time last week and now had frozen. I turned them both over.
For the can with the least amount of water, this is what I saw when I turned it over...
As you can see, the round of ice fell out of the can and split in half. Very logical. I think there is even some leaves mixed in there.
The second can had collected a good deal more water, before it froze. After turning it over, and the ice falling to the ground, this is what I saw...
Another view:
Since this was flipped upside down, what we are seeing is what happened at the bottom of the can. There is a round of ice that hugged the edges of the can, but then there is this big cavern - like a big loaf of bread that had an air pocket. Underneath (which was on top when the can was upright) is several inches of solid ice.
So it appears that the ice froze in mid air. Very illogical.
Any ideas?
7 comments:
IT all has to do with the freezing process of water and how it works. Except for a couple of rivers in the world (One of them is in Montana), water freezes from the top and procedes down. That's is because the coldest part of the the water is the part nearest the air. Once that freezes, it is the coldest, and the the liquid next it begins to freeze. IT takes quite a bit of energy loss to go from liquid to solid. Anyway, it's a good thing it works this way, or there would be almost no life in the rivers and lakes.
AL
Thanks, Al... I think I know some of that, but my question was about the air pocket... under the ice. There was no water in there when I turned it over...
That's a little harder, but has to do with how the water freezes. Not the process, but the way it crystalizes. You know that ice expands as it freezes into a solid. That means that it also moves upward; So depending on how much water there was to start with, it reaches a point where the center, which is freer to expand than the sides, loses contact with the surface of the water. You did note that the sides of that cube were much longer so I am assuming you realize that the sides maintain contact with the surface much longer. Part of that is due to two things. Mostly because the ice will stick to the sides especially if the sides aren't perfectly smooth or clean, but also because even if they didn't, there is still Laminar flow of fluids. Basically, that means that fluids in contact with a still surface tend to move slower than fluids that are farther away. So the end result is that odd looking ice "cube" with the air pocket. If there had been enough water and time, you could actually have gotten an ice cube that was hollow in the center and had the sides and top and bottom closed. Pretty neat, huh? I hope that helps explain better.
AL
see shoulda asked the chem student, now if you want to talk about data storage systems...
Believe me, I know that you know more about that sort of thing than I do... I would be willing to ask you if I had a question.
AL
Patricia Ann, i see that you wanted to keep your little toes warm with the wonderful sorrels, looks like you are keeping them white too. I have nothing to say about water freezing except i know that the temperature has to be damn cold and alot of that goes on over here. M.M.
After all the explanations, I think it is a physics issue. As is most of stuff in life.
Al.. Thanks again for the explanation. What still perplexes me is that there was no water at the bottom (and now top) of the ice cube. I can't imagine the cube having an air pocket surrounded by ice on all sides - the way it is now. Perhaps if the weather would have been different...
M.M.: I am imagining you in school, and summing up your observations - the teacher would definitely want to keep you after school.
As for the Sorrels, they are in the closet - they were used once.
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