metalresearcher
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Registered: 7-9-2010
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The Ultimate Thermometer Test
Here I checked five temperature measuring devices with melting snow.
The best is that is converts to slush by adding some tap water.
The values measured are:
1. Mercury thermometer -10-250oC : 0oC
2. Mercury thermometer -10-150oC : -0.5oC
3. Meat bimetal thermometer 0-100oC : -1oC
4. Type K thermocouple provided with an infrared thermometer:+1.8oC
5. Type K probe connected to a multimeter with type K readout: +0.9oC
So the deviatons are not negligible. I had to push the slush to keep contact with the five sensors.
EDIT: I tested a sixth one a type S thermocouple which measured -2oC but this thermocouple gives varying (+/- 2oC) results per 'session' (i.e power on
wait a few minutes - measure - power off). The readout is a Sestos temperature controller for a Kanthal furnace.
[img src=thermot est2.jpg
[img src=thermot est2.jpg
[Edited on 2010-12-4 by metalresearcher]
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The WiZard is In
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Registered: 3-4-2010
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Mercury thermometers for scientific use are generally of two
types — those designed/calibrated for full immersion or
partial immersion (value on the stem). A decent thermometer
also has a stated +/- temp value.
Some years ago the Amateur Scientist in Scientific American
had plans on building a thermometer accurate to one-hundredth
of a degree.
This all be reminding me of an old saying —
A man who two watches will never know the correct time.
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