So, at 0°, H2
O molecules will be escaping ice into the liquid portion of a cup:
as well as H2
O molecules from liquid portion will enter the ice cube. Both of these processes happen at the same rate, so the exchange of molecules is said to be at equilibrium.
But, what if... you catch a few molecules that escaped the ice state, and then you collect them. Would this affect the overall state of water in a cup? Or will it still balance itself as its temperature is at 0°.