Janet Baraclough wrote:
> The message >
> from Julia Altshuler > contains these words:
>
>
>
>>Take an ordinary household glass. Fill it with ice cubes. Then fill it
>>with water. The temperature of the water is now exactly 32 degrees
>>Fahrenheit.
>
>
> Um, doesn't that depend what temperature the water was when you added it?


I tried to make it clear from my original instructions that I was
talking about ordinary household conditions, not something that could be
dreamt up in a laboratory. If the glass was huge, the ice cubes small
and few, and the water boiling, then yes, it would depend on the
temperature of the water.


But under normal circumstances, as long as the ice is melting into the
water (outside air temperature is higher than 32) or the water is in the
process of freezing into ice (outside air temperature is lower than 32),
then the water is 32 degrees. If you want to get really technical, you
might want to wait a minute to make sure the ice has a chance to start
melting into the water.


Furthermore, some variables that others have mentioned would make a
difference. If, for example, you were using salt water or extremely
hard water, the temperature would change. But I was assuming we're
using ordinary drinking water from the tap.


This nifty trick is an easy way to test thermometers with readily
available equipment.


--Lia