Exploring Freezing Conditions of Salt Water Solutions Relevant to Icy Moons

Observations by the Galileo probe show that Jupiter's moon Europa has a massive ocean of liquid water beneath a shell made of water ice. The thickness of that shell, and thus the conditions of the ocean below, depends on many factors including the salt composition, salinity level, and pressure of the water. Our research aims to model different these conditions by measuring the freezing points of different salt water solutions at various pressure levels. We do this by undercooling a sample of salty water, nucleating it, and measuring the point at which the temperature plateaus during nucleation; indicating the freezing point. We currently have freezing point measurements for distilled water, KCl, MgSO4, NaCl at 5% salinity, and MgSO4 at 10% salinity. Recently, I have been preparing a second experiment set-up that can work at higher pressures and lower temperatures than the old system. In order to make sure this new system can get accurate data, I have been running experiments with distilled water and comparing my results to known freezing points. In the future, we plan on taking measurements for other salts like MgCl2.