Science Buddies: "Ask an Expert"

I took some notes on water and they don't make sense. The notes say that the density of water at 0 degrees Celsius (in the solid form) is .92 g/cm3, and that the density of water at 0 degrees celsius (in the liquid form) is 1.00 g/cm3. How is this possible??? If the freezing point of water is 0 degrees, then how can it be found in the liquid phase at that temperature???

hurleyan - As you probably know, ice has a lower density than liquid water, that's why the 1.00 vs 0.92 g/cc metric. If you slowly cool water to 0 degrees C, it will not immediately turn to a solid form at that precise temperature. It will continue to give up heat while still reading 0 degrees C for a period of time. For water, this heat of fusion is an approximately 80 cal/g. This is latent heat or 'heat of fusion'. Research these terms or 'enthalpy of fusion' for a more detailed explanation. Good luck in better understanding this interesting phenomena.

Rick Marz

Thank you. I guess that I didn't realize that water wasn't immediately a solid at 0 degrees C. Thanks Again!

hurleyan