Temperature. Equilibrium

In every one, I've seen the sensing element - whether bimetal strip, mercury column or electronic sensor - is suspended with the case, so they are actually experiencing the inner case air temperature.

The temperature will be the heat in vs the heat out. So on a cold day, they will be warmed by the skin and cooled by the air. On a proper hot day, the other way around. The Heat Transfer calcs for this is hurting my head... conduction through the skin-case-inner air, case-crystal-inner air, conductivity of skin v. air, area in contact...not even going to try.

Suffice to say that on the Aqualand which has a heavy stainless case, it takes about 5 minutes to stabilise on the wrist, but again, that's dependent on the inital temp of the watch, etc etc.

They are useless as thermometers when against the skin in air. Underwater, the far more effective thermal conductivity of water (approx 25 times air) and the fact that they are effectively surrounded by a water sees the temperatures change/reach equilibrium much faster, within the minute sampling rate of the temp sensor.

That'll do for today's nerdiness.

💰9 Marketplace Listings for Citizen›

Watches with thermometers?

By: cazalea : May 12th, 2011-11:42

Anyone have pictures of watches with thermometers built in? This is pplater's nice orange-dialed thermo watch (above) and mine with similar design (below) His clearly has an extended-range thermometer, but mine has a nicer set of Arabic numerals Now you c...

Love these all!

By: amerix : May 12th, 2011-11:51

and a timely reminder - never go out for a swim and leave your watch to bake in the sun - even for a few minutes. Cheers, amerix

Marie Antoinette

By: aaronm : May 12th, 2011-13:05

I don't have a picture handy, but the Marie Antoinette PW by Breguet (both the old and the new) have a bimetalic thermometer, if my memory holds a

Three different concepts

By: Marcus Hanke : May 12th, 2011-13:33

First, the classic "mechanical" thermometer, by Ball: Then, the integrated multi-function quartz watch, although with analog hands, the Tissot T-Touch: Finally, the modular concept of a multi-functional modul on a mechanical watch: "The Rock" by Linde Wer...

Great!

By: cazalea : May 12th, 2011-14:47

Thanks for the view. I thought there was a thermometer as one of the 4 options in my Seiko "Contra", but it wasn't so. It had a timer and trip meter plus these too. I know I have had another thermometer watch, what was it .... ? hmmm...

Aqualand

By: BDLJ : May 12th, 2011-19:44

No mercury, just batteries in this one....

Ball TMT

By: VMM : May 13th, 2011-03:42

Vte...

I like this watch

By: cazalea : May 13th, 2011-06:54

I thought about getting one when they were first released, then I completely forgot about them ... maybe time to put back on the list? Cazalea

Vianney of course !

By: foversta : May 15th, 2011-14:24

With the Satellarium: Fx...

Here are a few more (therm not halter)

By: cazalea : May 15th, 2011-15:06

I dredged these up around the web. A LIP diver with thermometer on the crystal A pocket thermometer that sold at auction for around $4000 Here's a dual-time watch with smiling face thermometer (no longer filled with mercury) And a "swiss army knife" versi...

I love that vintage pocket thermometer

By: AndrewD : May 16th, 2011-21:25

But I wonder what all these watch thermometers are actually measuring and how long they take to equilibrate? On the wrist it must be an average of skin and air temperature? Interesting thread. Thanks. Andrew

Temperature. Equilibrium

By: BDLJ : May 16th, 2011-23:50

Funny, the first inventive iteration from a Chinese fake watch ...

By: Marcus Hanke : May 17th, 2011-00:32

... the Alpha apparently stems from one of the many Glycine copies around, but where normally two tiny movements are at 8 and 10, permitting two separate time zones to be displayed, here we find the much more interesting barometric and temperature counter...