Freezer Temperature / Ice Temperature

Because of thermal gradients (i.e., warmer and colder spots) in the freezer, getting an average temperature might be tricky. I think I would go for a sensor placed in the air stream at the opposite side or end from the cooling coil.

I was thinking average in the sense of time averaged, not positionally averaged.

I wouldn't worry about the ice cube. Just put the thermocouple into the freezer (if any wires need to extend out of the freezer, make sure to minimise any leaks to ensure accuracy).

You could freeze the tip of the thermocouple in the ice cube. This would provide some buffering against experimental error (opening and shutting the freezer door).

Hope this helps.

My motive for getting an average temperature from an ice cube is that I was hoping to get a faster/simpler temperature recording (for specific reasons) than from time averaging with a sensor in the freezer.

An interesting observation that I can't explain ... if I measure the temperature of a melting ice cube (ie taken out of freezer and surface is wet) the temperature reads just over 0 C, but if I measure the ice temperature with the freezer door open (ice does not start melting) I measure -16 C. My freezer peaked out at about -20 C so maybe -16 C is a reasonable average.

(And the triple point of H₂O is...?)

... "if I measure the temperature of a melting ice cube (ie taken out of freezer and surface is wet) the temperature reads just over 0 C" ...

Ice melts at 0degC, so this makes sence if you are measuring the surface of the ice cube. Where the ice is melting, the temperature would be almost exactly 0degC.

If you were to measure the temperature within the ice cube, it would remain at low temperature for some time (while still frozen) before rising only as the ice melted.

Don't confuse temperature with heat (or more accurately the transfer of energy as heat). When you remove the ice cube there is an immense amount of heat transfer occuring (as there is a large temperature gradient between the ice cube and the environment). But while the ice cube is in the freezer, there is far less (if any) temperature gradient between the surface of the ice cube and the environment, therefore much lower heat transfer which gives you a much lower surface temperature.

Hope this helps.

Anthony

You should accept the fact that your freezer is cold enough to freeze water and move on to a more worthwhile endeavour, such as helping this poor child find her way to (get) christian members on a trip to Jerusalem.

Mathematics / Economic