Still Water as an Approximate Blackbody

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Discussion Overview

The discussion centers on the feasibility of calculating the temperature of still water using Planck's Blackbody Radiation principles. Participants explore the theoretical and practical aspects of this calculation, including the role of emissivity and potential complications in measurement.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions whether the temperature of still water can be calculated using blackbody radiation principles, specifically referencing an intensity image of the water.
  • Another participant suggests that it might be possible to calibrate an infrared thermometer against a regular thermometer, but expresses skepticism about various factors that could affect accuracy, such as angle of incidence and container effects.
  • A follow-up question asks if it is theoretically possible to perform such a calculation.
  • A later reply affirms that it is theoretically possible to calculate the temperature, provided that emissivity is known as a function of wavelength and temperature, and that the water is deep enough to ensure a long enough path length.

Areas of Agreement / Disagreement

The discussion does not reach a consensus, as participants express differing views on the practicality and theoretical aspects of calculating the temperature of still water using blackbody radiation principles.

Contextual Notes

Participants note potential limitations related to emissivity, measurement conditions, and the assumptions required for accurate calculations.

Who May Find This Useful

This discussion may be of interest to those studying thermodynamics, infrared measurement techniques, or the properties of water in scientific contexts.

ecastro
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Can the temperature of a still water be calculated using Planck's Blackbody Radiation? For instance, I have the intensity image of water (of course, this is considered still, as it seems that it is currently stopped in time), and I want to calculate the temperature of the water, is it possible?

Thank you in advance.
 
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https://en.wikipedia.org/wiki/Infrared_thermometer
In principle, given emissivity as a function of wave length and temperature. You might be able to "calibrate" an IR thermometer versus a regular thermometer to do the "heavy lifting;" but, I'd be very suspicious of angle of incidence, container effects, and other interference.
 
But can I calculate it theoretically?
 
"Is it theoretically possible to calculate it?" Yes, given emissivity as a function of wavelength and temperature and a long enough path length (deep enough water).
 

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