Which Material has the Lowest Freezing Point?
The material with the lowest freezing point is helium. Under typical pressures, it does not freeze at all, even at temperatures approaching absolute zero. The reasons why are dictated by quantum mechanics: the zero point energy of a helium system is too great to allow freezing. The zero point energy is the minimum energy a particle or system always has, no matter what. Helium is the only substance that does not have a freezing point under ambient pressure, no matter the temperature. A freezing point for helium only exists under at least 25 atmospheres of pressure and a temperature of 1.15 K. These conditions have been created in a laboratory through evaporative cooling. The result is a colorless, highly compressible solid that is practically invisible. Solid helium is so difficult to see that layers of styrofoam are used just to tell where it is. The density of solid helium itself is only 66 times greater than air. By comparison, water is 1000 times more dense than air. Helium was firs
