Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: syhprum on 11/12/2010 13:01:26

Title: How can I make accurate temperature meausurments
Post by: syhprum on 11/12/2010 13:01:26

It is easy enough to make a simple Mercury in glass thermometer and calibrate it with boiling and melting water but there are many sources of error.
If I wanted confirm that a temperature was 30.01°C and not 30.02°C how could I do it ?.

Title: How can I make accurate temperature meausurments
Post by: Bored chemist on 11/12/2010 13:55:04

With some difficulty and, probably, a platinum resistance thermometer.
http://en.wikipedia.org/wiki/Resistance_thermometer
Fortunately for you the temperature you are looking at is very close to the triple point of gallium which is accurately known (29.7666°C or 302.9166 K) so you could probably extrapolate to 30.01 or 30.02 degrees.

Title: How can I make accurate temperature meausurments
Post by: syhprum on 14/12/2010 22:03:36

I am grateful for your hint that I can use Gallium to calibrate my thermometer but how has its triple point been determined to one part in ten thousand ?