Calibrating thermometers?

[marcelft]

OK..I have two thermometeres, a digital one says Im at 75.2 degrees, and a red lined old school termometer that says I'm at around 79 degrees. How do I tell which one, if either, is correct?

[kolosy]

buy a third.

seriously, that's what i did.

[marcelft]

<a href=showthread.php?s=&postid=13719881#post13719881 target=_blank>Originally posted</a> by kolosy
buy a third.

seriously, that's what i did.

Now that's funny...but I hate math, even though finding the mean of three numbers isn't to difficult. There has to be a better way.

How about sticking them in a glass of crushed ice water, should read 32 degrees right?

[buccard]

<a href=showthread.php?s=&postid=13719967#post13719967 target=_blank>Originally posted</a> by marcelft

How about sticking them in a glass of crushed ice water, should read 32 degrees right?

I have had the occasion to calibrate a thermometer in my line of work and that is exactly how I do it! ice and water in the same system have to be at 32 degrees just make sure the mixture is consistent. Ice just on top 2 inches of an 8 inch glass of water may give inaccurate reading depending on the depth you sample.

You can also use the other end...boiling water @ 212F if your thermometer operates in that range...more risky though.

[marcelft]

<a href=showthread.php?s=&postid=13720088#post13720088 target=_blank>Originally posted</a> by buccard
I have had the occasion to calibrate a thermometer in my line of work and that is exactly how I do it! ice and water in the same system have to be at 32 degrees just make sure the mixture is consistent. Ice just on top 2 inches of an 8 inch glass of water may give inaccurate reading depending on the depth you sample.

You can also use the other end...boiling water @ 212F if your thermometer operates in that range...more risky though.

Ok..so I dropped my Marineland digital thermometer and regular red-lined thermometer in a glass of RO/DI ice water and the digital reads 30.1 degrees, and the redline reads 34. So, both are wrong in the opposite direction!! But, the mean of the two does equal 32!!

[buccard]

LOL...take the average!

[marcelft]

Mean = average. Just one more way of saying the same thing and confusing us all.