Need to calibrate your thermometer?

[mayberrygirl]

Now this only works with a thermometer that goes down to at least 30 and is either a digital meat type or a type that can be at least partially submerged. I calibrated my meat thermometer today to check for accuracy of my other thermometers n the bator... (my hubby has worked in fast food management and in the Health Dept for our county, this is how they do it -

1 cup ice
1 cup cold water
let sit for a couple mins
place thermometer in

you should have a reading of 32*

 

[Irish Ridge]

Cool, how come I never thought of that? I've been wondering how much my thermometers have been off. Thanks!

 

[babsbag]

I also know that at sea level your water should boil at 212. But that only works at sea level and for thermometers that can be put in water. Won't work for those digital ones we buy at Walmart. I never thought about putting one on ice. Good idea.

 

[CityChicker]

In theory, the freezing point of water is 0 degrees celsius and the boiling point is 100 degrees celsius. There are a couple of things that I have found very frustrating about calibration. First things first, a lot of the mercury thermometers made for incubators do not go low enough down in reading for calibrating by the freezing point! That is so silly to me. The other option is calibrating by boiling point, but this is more difficult in general because of the precision required for incubator thermometers (knowing when exactly to take the reading since it is harder to tell the point when the water boils than it is to tell the freezing point with the ice water) and because of the issue with altitude. As you go higher in altitude, the boiling point drops significantly. Ours here is only about 92 degrees celsius. Again though, you have to be so precise because of how narrow the successful incubation range is.

I have come to believe that digital thermometers are just not accurate. My dad (who is a college professor that deals with thermometers daily) insists that mercury is the way to go. You can calibrate some digital ones by taking them apart to expose the probe and then doing the same tests as above. It is a lot of hassle though when mercury is so easy to use.

As a side note- I would love to do a study on whether or not boiling point at high altitude may have a significant affect on hatch rates, since eggs are obviously mostly liquid. It would only stand to reason that temps. should potentially be lower the higher you go. I have never seen any authors mention this though. Anyone that has hatched at high elevations knows, it is quite a challenge.

 

[chickintexas]

And here I was wondering about my meat thermometer! I've been using it in a makeshift water wiggler (a baggie filled with water with the probe of the meat thermometer). I'll check on the temp right now. Thanks for the hint!!

 

[chickintexas]

My meat thermometer registered 32 on the dot. Good to know.

 

[mayberrygirl]

Happy to help!

 

[babsbag]

Quote:
Wouldn't that make an interesting, but near impossible science experiment. Since there are so many variables to the artificial hatching it would be hard to draw any firm conclusions IMO. But still interesting. The thing is though, the hen doesn't do anythin differently so how does that work?

Ask your dad about calibrating a hygrometer. The question that came up the other day is this.

Someone said that percentage off is calculated not by the degrees off on the hygrometer, but by percentage off such as...85/75....1.13%. So, if your reading is 85 in the bag, you hygrometer is 1.13% off, not 10%. To find out what your hygrometer will read for a 50% humidity, you need to multiply 1.13 x50=56.6.

I asked my brother, who teaches chemistry and he gave me a very long explanation that made sense to me but too hard to explain. I would be interested in knowing someone else's take on that. Not that there is a hugh amount of difference between 56.6 and 60, but I am just curious.

 

[Penturner]

babsbag, the temperature that an egg is incubated at does not change with altitude. Water boils at a different temperature because of atmospheric pressure. You can in reverse place water in a pressure chamber and prevent it from boiling at 300 degrees. that does not mean it is not 300 degrees it just means it does not expand to a gas (Steam and evaporate. Also known as boiling. You can still calibrate any thermometer at any altitude. you either need to know the boiling point of water at that altitude or but the water and thermometer in a pressure chamber at the pressure of sea level.
As for the hygrometer being off by a percentage rather than a definite number. For me that is sort of like well duh. did anyone realize they are reading a percentage in the first place? But still it does not matter. the difference is what is considered insignificant. This means the amount you will actually be off is not enough to worry about. For example the calibration set up says I should read 75% but mine reads 65%. I can simply add 10 to any reading or realize my meter is off by 7.5%
I want my bator to be 50%. so I adjust water containers until I read 40% and add 10. in truth my humidity is 46.5%. In actual practice the difference is actually even far less than that.
One very frustrating thing about digit metering is that electronic component change with temperature. so a thermometer that is very accurate at room tamps like 70 degrees can be completely off the track at 99.5. For this reason alone I consider liquid and better yet Mercury thermometers to be the only reliable ones.

 

[chickintexas]

Penturner-I was wondering about the fluctuations at higher temps. All my thermometers read pretty much the same at room temp but once the temp goes up, I get readings all over the place. I'll have to post a picture of just how many thermometers I've got set in my bator right now.My husband already thinks I'm nuts.
I'm curious about the speed at which the liquid thermometer goes up and down though. While the liquid reaches it's optimum read, the digital ones may go one to two degrees higher. One is a metal tipped sensor and therefore hits the high and low peaks the fastest versus the plastic tipped sensors which are a tad slower to pick up the temp changes. For some reason, I trust the liquid one more out of all of the digital ones I've got lined up right now. I could make quite a bit of money back after I return them to the store.