Why Does Covered Ice Tray Freeze Ice More Effectively?

[Curious jack]

i fill two ice trays, one covered and one not. The ice in the covered tray freezes the ice to the point that the ice is much more difficult to extract from the tray. Why is that?

 

[Borek]

Please elaborate, your desciption of the 'experimental procedure' is too vague.

 

[Curious jack]

i fill two ice trays, one covered and one not. The ice in the covered tray freezes the ice to the point that the ice is much more difficult to extract from the tray. Why is that?

To restate: When I fill the two plastic trays with water, I place the two trays in my freezer.Then, I place a cover over one tray.
the ice tray not covered is much easier to extract the ice from. Meaning, I simply turn the plastic ice tray over, twist it and all the cubes easily fall from the tray. Conversely, the tray that I placed a cover over requires more effort. In fact, after twisting the tray to the point of cracking the ice tray, I always have to run water on the top and bottom of the tray before the ice cubes will fall from the tray. Why is that?

 

[russ_watters]

I've noticed that ice cubes left in the freezer too long will sublimate and in particular, you'll get a gap between the tray and cube. But cover the tray = no sublimation.

 

[Curious jack]

I've noticed that ice cubes left in the freezer too long will sublimate and in particular, you'll get a gap between the tray and cube. But cover the tray = no sublimation.

Thanks russ. One more point to my experiment: We're not talking long term freezing. Both trays were put in the same time, and within 2 days, both are removed. The above results continually proved that the tray covered required water from the faucet to separate the ice from the tray. While the ice cubes from the non-covered ice tray simply/freely fell from the tray with only one twist of the tray -no water from the faucet required.

 

[Borek]

How long after trays are removed from the fridge? Can it be in any way connected with the fact that after removal the one covered was isolated from the air around and was colder when you remove the ice? Have you always covered the same tray, or have you done it at random? Have you always placed both trays in the same places in the fridge?