
10
Phases and Their Equilibria
We are all familiar with the sight of ice floatingonwater.Infact,evenonawarm
day, we can toss an ice cube into a glass of water. What happens subsequently is
that ice starts melting and will take quite some time before completely melting into
water. In the interim, both ice and water are existing together. Can this be called a
state of phase-coexistence? Strictly speaking not, because this is not an equilibrium
situation. It is not a state of equilibrium because as time goes on the amount of ice
left changes.
Our next question is whether we can arrange for a truly equilibrium coexistence
of ice and water? It can indeed