# Why did my saline solution not expand significantly when frozen?

Three days ago, I put a fully saturated solution of salt in water in an open-top glass jar. I wrapped the jar in a plastic bag in case it exploded, but when I returned in the morning, it had formed ice crystals suspended in brine. Two days ago, I repeated the experiment with about twice the previous quantity of solution in a sealed jar. When I opened my freezer this morning, the jar was intact... but completely filled with a solid block of ice. There is the barest hint of a liquid layer at the bottom of the jar, but otherwise, state of the original fluid aside, matters seem to be as I left them. The height of the liquid in the jar is about the same as I left it. Despite being almost completely full originally, the ice hasn't expanded. What is happening?

Correction: the ice did in fact expand by a small amount. As predicted below, my measurement technique was off. Thank you all for your patience.

• "the ice hasn't expanded" Please clarify your question to specify the measurement technique you used to conclude an expansion of exactly 0%. I don't see how this how possible—every measurement technique involves some level of error. Commented Feb 2 at 6:30

First thing is that there's no evidence from your side to backup your claims,hence definite answer can't be provided. But some reasoning can reveal the truth.

No change in volume during phase transition implies independence of melting point or freezing point on pressure (clausius equation is to be invoked). This means no matters how high or low the pressure is ice will melt on same temperature which isn't true at all.

Also,The extent to which salt dissolves in water depends on temperature, if you cool brine the salt will certainly precipitate as crystals (and you haven't accounted for it) it maybe possible that somehow the change in volume by two processes balanced out and no (or negligible) change in volume was observed. But there's a point, water expands on freezing so the salt should contract on crystallization to balance it out, but is it true?

The partial molar volumes of most of the studied salts are less(in aqueous state) than their molar volumes in the solid state.

Ref

This means that volume should increase due to precipitation of salt crystals.

I believe both arguments are enough to debunk your claim! The observation is definitely flawed.