Help testing thermometer accuracy


In the Brooder
7 Years
Oct 24, 2012
Otsego, MI
My Coop
My Coop
I just tested the thermometer that came with my LG incubator. I saw it in ice water for about 10 minutes. It quickly moved to 50 degrees and stopped at 40 degrees for the last 5 minutes. So it was showing that my water with ice still floating in it was 40degrees. Is this accurate enough of a test to assume that it is ready 8 degrees higher than the correct temperature?

My intention is to use this thermometer to test my digi thermometers accuracy.

This is what the test looked like - this is about 3 minutes in when the temp is still dropping
Why are you saying that it is 8 degrees higher?
just because there is ice floating in water does not mean the water temp is at 32
otherwise the water would (should) be starting to crystalize.

Put both thermometers in there together and see if you get a matching result in a side by side comparison of exact conditions
I re-tested with a class full of crushed ice and a little bit of water and got a better measure of 34 degrees! I wasn't able to do it with the digi because it is an internal probe. I think that the thermometer is pretty accurate
since it's an internal probe you could sick both of them inside the refrigerator and see if they match that way. of just go straight to the incubator with them.

I have 4 thermometers that i calibrate with in my incubator. sometimes one can go astray and mislead you but if the other 3 match i know which one is off

I have redundancy with my Thermostats too ...... my cabinet has 3

one is the "set point" that does the work of hatching. at 99.5 degrees
the second one is set as a "high Limit" at 100.5 degrees
and the third is set as a "low limit" at 98.75 degrees
Awesome thank you. I now have three medical thermometers and a digi. This is my first time incubating so I'm a worry wart.

update: the two aquarium thermometers are reading at 100* exactly as well as the digi. The LG thermometer is reading about 102. I think i'm doing ok. Our house is warmed with a pellet stove, so I'm a little worried about the affects starting to heat the house. Maybe I'll just pull the other plug out what that happens?
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I checked 9 thermometers yesterday, and even the ones from my sportsman's were off 5° from each other. I'm going to find a medical grade one today , to find out which ones are right.
This is insane, just finished checking my thermometers against 2 new people thermometers, the $28 gqfs are reading 2-3.5+5° low. I'm glad I only put 30 eggs in the sportsman last night, and hopefully 24 hours of 102° didn't cause too much damage.
The original thermometer that came with the Farm Master is within 3 tenths of a degree.
I would recommend buying a dgital thermometer from a drug store and calibrating your incubating thermometers at 100°,that's where it matters, not down at 32° .
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