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In this episode we discuss various methods to measure temperature, and how to use temperature measurement to make a voltage measurement. In particular using what is called a thermal voltage converter which is used to determine AC and RF voltages.
This episode was recorded before the Measurement Science Conference, but then I had a hard drive crash, and had to recreate a lot, including the opening sequence. This episode is a continuation of the previous topic and covers the topic of the constant volume gas thermometer and thermodynamic temperature. How one measures pressure is first discussed, and then how pressure can be used as a thermometric property to define thermodynamic temperature.
It has been awhile since our last podcast, and we hope we can start putting them out more often. We want to try adding some short video podcasts that will be done between our longer ones. We will see how that goes.
I would like some feedback on what topics to cover in the podcasts. If you have any topic related to science and engineering that you would like to see something about, let us know.
This episode is about temperature. We are planning this being the first of a short series on the subject. A broad overview of the subject is given in this episode, with some of the history of temperature scales. The “zeroth” law of thermodynamics is described, as well as some of the basic concepts associated with temperature measurements.
I just realized the wrong file was pointed to for episode 43, it actually pointed to episode 9. Sorry about that. Here is episode 43 again, with the correct file. I am currently shooting Episode 44, so look for that soon.
Example Blackbody Source - Image via Wikipedia
In this episode the topic of blackbody or thermal radiation is discussed. This is a connection between radiometry and photometry and temperature measurement. Discussed are blackbodies and what are called greybodies (blackbodies with emissivities < 0.99) Blackbody and greybody sources are used in the calibration of radiometric devices. The sun, stars, and the whole universe emit spectra consistent with a blackbody spectrum, as does every body at finite temperature. This is why one can measure temperature approximately by observing the electromagnetic radiation emitted from matter.
The spectral radiance (power radiated per unit area per unit solid angle per unit wavelength) of a blackbody is goverened by what is called Planck’s law:
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This can be integrated to give the total radiant exitance (power radiated per unit area) F=σT4.
