Historic experimental evidence of Kirchhoff's radiation law

In summary: The book recommendation is the six-volume set by J. Mehra and H. Rechenberg. In summary, Kirchhoff's radiation law was postulated in 1859, and it was not based on measurements of spectral data. The actual measurements of black-body spectrum would not be possible until 1880, with the invention of the electrical bolometer.
  • #1
fsonnichsen
62
5
I am curious about the historic experimental evidence that lead to Kirchhoff's radiation law. It is easy to take for granted the ubiquitous temperature/wavelength curve that lead Planck to the quantization concept. But I wondered historically how the curve was derived.
To clarify, we routinely see this spectral distribution in the laboratory with a simple benchtop spectrometer consisting of a dispersion grating and photdiode array. One can plot the relative intensities from the latter and reveal the curve.
But how was this done in the time prior to such a device? I believe that in Kirchhoff's time the only spectral device was the "spectroscope", perhaps with a photographic plate. How were the relative intensities determined? I could not locate the key papers from that time.

thanks
Fritz
 
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  • #2
Kirchhoff did not measure spectrum, but just postulated (in 1859) the wavelength dependence being the same for all black bodies. The argument used hole-based black body and 2 heat sources (artificial one and sun).
The actual measurements of black-body spectrum would not be possible until invention of electrical bolometer in 1880.
 
  • #3
How about a book recommendation? The history -- Kirchoff to Boltzman to Plank to Dirac et all.
 
  • #4
OK trurle. This makes sense and confirms my expectation.
I find that this whole area of physics, the precursor of quantum mechanics, is very poorly described in most of the texts I have here. It is "glossed over". How the experiment was done, whether in the lab, or from the armchair, is important as certain conditions are probably being assumed which are often not mentioned. Thus the cavity can be a conductor, leading to an electrical field boundary condition of zero at the walls etc. Obtaining the original papers is difficult for me. As anorlunda implies an appropriate book would be of value, perhaps excerpting the original papers and diverging a bit to divulge what the exact formulation of the problem is.
I never quite understood for example what the boundary conditions where, how a heated sphere is equivalent to a box with a cavity in terms of standing waves, why the waves are standing etc. And very important the necessary conclusion that the wavelengths must be quantized to avoid the ultraviolet catastrophie is poorly explained.
Thanks--Fritz
 
  • #5
Well, if you find everything you've read about this history lacking detail, here's perhaps what you want ;-)):

J. Mehra, H. Rechenberg, The Historical Development of Quantum Theory, 6 vols. , Springer

It coverse however the history from 1900, not before.
 

1. What is Kirchhoff's radiation law?

Kirchhoff's radiation law is a fundamental principle in thermal radiation, which states that the ratio of emissive power to absorptive power of a material at a given temperature and wavelength is constant. This means that a material that is a good emitter of radiation is also a good absorber of radiation at the same wavelength and temperature.

2. Who discovered Kirchhoff's radiation law?

Kirchhoff's radiation law was first proposed by German physicist Gustav Kirchhoff in the mid-19th century. He developed this law while studying the properties of thermal radiation and its interaction with matter.

3. What is the historic experimental evidence of Kirchhoff's radiation law?

The historic experimental evidence of Kirchhoff's radiation law includes several experiments conducted by Kirchhoff and other scientists, such as Robert Bunsen and Julius Plücker. These experiments involved measuring the emission and absorption of thermal radiation from different materials at various temperatures and wavelengths, and consistently showed that the ratio of emissive power to absorptive power remained constant.

4. How does Kirchhoff's radiation law relate to other laws of thermodynamics?

Kirchhoff's radiation law is closely related to the laws of thermodynamics, specifically the second law which states that heat flows from hotter to colder objects. This law helps to explain why a material that is a good absorber of radiation is also a good emitter, as it allows the material to reach thermal equilibrium with its surroundings.

5. What are the practical applications of Kirchhoff's radiation law?

Kirchhoff's radiation law has numerous practical applications, particularly in fields such as astronomy, remote sensing, and thermal imaging. It is also used in the design of energy-efficient buildings and in the development of materials for specific thermal properties. Additionally, this law is the basis for the development of Kirchhoff's law of thermal radiation, which is used to calculate the spectral distribution of thermal radiation from a body at a given temperature.

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