Thermometer Calibration

[Intheswamp]

I've seen several messages about calibrating hydrometers but I got to wondreing about calibrating a thermometer.

Upon searching around it looks like the "Ice Point Method" of thermometer calibration should work pretty good for either dial or digital thermometers. Basically it is filling a container with crushed ice and water, allowing the ice water to stabilize for 4-5 minutes and submerging the probe/bulb into the center of the slush...the resulting temperature should be 32F...be sure to use crushed ice and not ice cubes.

Here is a link pertaining to this:

Indiana Department of Public Health "Ice Point Method"

Ed

 

[pascopol]

Quote:
I don't really know how can you "calibrate" a thermometer, there is no screw, or a knob on any thermometer I ever seen.

All you can do is to check its reading with Ice Point Method or compare it to another which is believed to be true, then take mental correction of its readings if the thermometer is off.

 

[patandchickens]

Well, pretty clearly that is what's being MEANT by calibration, here

It is not semantically unreasonable.

Anyhow: I'd suggest not relying on ice... the correction factor is not necessarily going to be a constant # and you really care about accuracy near 100F not near 32F.

Medical thermometers (like the kind you buy at the drugstore for seeing if someone has a fever) are pretty accurate, compared to what's needed for incubation anyhow, so I would suggest putting a good fever thermometer side-by-side with your incubator thermometer in a cup of roughly 100F water, let 'em sit and equilibrate for 10 minutes or more, then compare readings.

New to incubation but not new to thermometers <g>,

Pat

 

[Intheswamp]

Quote:
I don't really know how can you "calibrate" a thermometer, there is no screw, or a knob on any thermometer I ever seen.

All you can do is to check its reading with Ice Point Method or compare it to another which is believed to be true, then take mental correction of its readings if the thermometer is off.

I agree with you about actually adjusting the reading of the thermometer...basically I figure we'll have to make that mental note as is recommended for hydrometers using the wet-salt method of calibration. Some of the metal stem dial-type thermometers can be adjusted, but the digitals that we mostly will be working with will require the mental sticky-note.

Ed

 

[CARS]

Quote:
I really wish that the word "calibration" wasn't used with any of these instruments. I like to take terms literally and to calibrate means to adjust to make accurate.

I know what you mean when you talk about accuracy tests, but could it be referred to "accuracy tests" in the future. It makes it confusing.

(maybe it's just me

)

 

[Intheswamp]

Quote:
Evening Pat. You've hit a bullseye with some questions I had echoing in my skull (echos happen in empty chambers). I was curious about how 32F would relate to 99.5F. The other option was doing the boiling point method and I really didn't think the plastic probes would stand up to that.

But what you've mentioned about comparing a medical thermometer with the incubator thermometer is what I was looking for when I stumbled upon the "Ice Point Method". I'm going to opt for the "comparison method" over the "ice point" one....simple enough! I might still try the ice method after comparing with the medical thermometer just to see how it works out.

I'm *very* new to incubation (like I don't even have an incubator, coop, or pen at the moment), I'm new to thermometers, and I guess you've caught on that I'm new to chickens....so if you ever see a message from me please feel free to respond, advise, suggest or whatever...I'll definitely be thankful for the guidance!(This goes for all you BYC folks!)

Ed

 

[Intheswamp]

Quote:
I really wish that the word "calibration" wasn't used with any of these instruments. I like to take terms literally and to calibrate means to adjust to make accurate.

I know what you mean when you talk about accuracy tests, but could it be referred to "accuracy tests" in the future. It makes it confusing.

(maybe it's just me

)

<chuckle> No, it's not just you...the following *is* "confusing"....

I've been researching chickens and trying to learn all that I can about them and about starting a flock up for only a month or so. I've been reading the forum for less time than that.

Well, the other day I start checking through the new postings and digging into some of the older ones when I start seeing everybody referring to eggs as "ROOSTER".(Yeah, yeah,...yeah) Well anyhow, I see everybody talking about their ROOSTER. Huh? It was "I set 14 ROOSTER in the incubator today", or "My DH loves 3 ROOSTER in the mornings", or "My broody hen is sitting on her ROOSTER". Now I'm a rank newbie remember and I'm going "What in the world!?"...I figured this must be one of those cultural, hobby, industry, or whatever terms used for eggs. I even thought to myself how I would refer to eggs as ROOSTER. The whole time I'm thinking that this is *really weird* and really couldn't remember seeing where anybody had referred to ROOSTER in this context before...but figured I'd just overlooked it. A younger guy that works with me told me it was probably a April Fools joke, but NO, it stated on the main page that a move to a new server had cause some bad problems, etc.,. Yeah, yeah, yeah...confused???...yeah, I know what confused is...as I stood there with ROOSTER on my face!

.

So..."accuracy tests" sounds cool to me!

Ed

 

[CARS]

I almost spit on my laptop Ed!! I missed April fools day other than in the morning I saw the "loss of post count". I kinda had a suspicion but...

OK, back to the OP's question (Original Poster) (I think

, who knows around here

)

 

[CloggingChicken]

You can calculate a correction for thermometers. You can actually send a precision thermometer or thermocouple in to several different companies and they will provide you the correction for your desired temperature point(s). They do this using a secondary standard corrected against the National Institute of Standards and Technology(NIST). We used to send off several thermometers every two years to be checked and then we would use those to come up with corrections for others that we used in the lab. The reason for checking every couple of years is that Glass is not a true solid and will change shape over time, as evidenced by looking at old farmhouse pane windows.
In short you are correct that thermometers cannot be "calibrated", however, you can figure out that one is so many degrees off when it reads 100 degrees.

Probably more info than you wanted, but for those that wanted to know about precision.

 

[CARS]

Quote:
No, good info!!!

Not more info than we wanted, just hard to justify for a $7.00 thermo/hydro unit