Freezing Point of Water
Most recent answer: 03/09/2015
- laxman chauhan (age 26)
india
This is indeed a puzzle. If the water is in a sealed chamber with some gas, cooling will cause the pressure to drop, which does raise the freezing point a bit. The highest it can go is the triple point, at 0.01°C, which is hardly a noticeable amount above 0.00°C.
My guess is that somehow your thermometer is not reading correctly. If the cooling is rapid, there can be big difference in the temperature between different regions. Perhaps there's a way to cool much more slowly. You might let cold nitrogen gas flow all over the copper block and see if you get a different result.
Another possibility is just that the thermometer is mis-calibrated. Have you tried putting it in an ice-water bath to make sure it reads 0°C?
Mike W.
(published on 03/09/2015)