Question

Stat mech explanation for separation of one liquid from another in gravity?

Answer 1

Because liquids, water in particular have a high surface tension.

For this reason blobs of water tend to become spherical. Now, given that it starts as an elongated stream (say because it's pushed out of a bottle), the stream breaks up in different pseudo-spherical bubbles; if an astronaut were to pour water very, very slowly and carefully he could create a single spherical blob.

The concept is not dissimilar to drops, but without the gravity.

Answer 2

Classical and Statistical Thermodynamics . ... Microscopic Interpretation of Heat and Work . ..... controls the flow of heat from one body to another when they are brought into thermal ...