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1 Forgotten experiments and the Plancks radiation formula. On the experimenal context at the birth of quantum physics. Jerzy Karpiuk Photochemistry and.

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Presentation on theme: "1 Forgotten experiments and the Plancks radiation formula. On the experimenal context at the birth of quantum physics. Jerzy Karpiuk Photochemistry and."— Presentation transcript:

1 1 Forgotten experiments and the Plancks radiation formula. On the experimenal context at the birth of quantum physics. Jerzy Karpiuk Photochemistry and Spectroscopy Laboratory, IPC PAS karpiuk@ichf.edu.pl

2 2 * A. Sommerfeld, Atombau und Spektrallinien, 1919, p. 4 14.12.1900 – birth date * of quantum theory "Das war eine rein formale Annahme, und ich dachte mir eigentlich nicht viel dabei, sondern eben nur das, dass ich unter allen Umständen, koste es, was es wolle, ein positives Resultat herbeiführen musste. (1931) It was a purely formal assumption and I really did not give it much thought except that no matter what the cost, I must bring about a positive end. (1931) Max Karl Ernst Ludwig Planck (1858 –1947)

3 3 Traditional point of view It is rare in any form of progress or in any discovery that the success can be with truth attributed to one man... But of Planck it can be said, and it is universally true that the formation of the quantum theory is his alone. H. T. Flint, Nature 181 (1958) 1098 Plancks unique position is best illustrated by what is in my opinion the singular fact that he had no precursors or competitors whose thoughts moved in a similar direction. E. Segrè, Phys. Bl. 23 (1967) 62 It is rare in any form of progress or in any discovery that the success can be with truth attributed to one man... But of Planck it can be said, and it is universally true that the formation of the quantum theory is his alone. H. T. Flint, Nature 181 (1958) 1098 Did Planck create them out of nothing? H. Kangro, Early History of Plancks Radiation Law (1976) p. 1

4 4 Plancks opinion... M. Planck on the nomination for the Nobel Prize in physics for 1908: It was not so that theoretical work paved the way for the experimental studies; more correctly is to say it was just the opposite." The Prize was then to be shared by a leading theoretician and a leading experimentalist, in this case perhaps Lummer". R. Torge: Otto Lummer, Fritz Reiche, Mieczysław Wolfke: Szkice biograficzne. Postępy Fizyki 53 (2002) 201 It seems as if the formula, once put in mathematical form, survived quite well, whereas the experiments on which it was first founded have relatively rapidly fallen into oblivion. H. Kangro, Early History of Plancks Radiation Law, 1976, p. 2

5 5 Rosencrantz i Guildenstern are dead Allan Franklin, The Neglect of Experiment, 1986 One of the great anticlimaxes in all of literature occurs at the end of Shakespeares Hamlet. On stage strewn with noble and heroic corpus Hamlet, Laertes, Claudius, and Gertrude the ambassadors from England arrive and announce that Rosencrantz and Guildenstern are dead. No one cares. A similar reaction might be produced among a group of physicists, or even among historians and philosophers of science, were someone to announce that Lummer and Pringsheim are dead. Jeden z największych zawodów w całej literaturze występuje pod koniec Hamleta Szekspira. Na scenę usłaną ciałami bohaterów – Hamleta, Laertesa, Klaudiusza i Gertrudy wkraczają ambasadorowie z Anglii I zawiadamiają, że Rosenkranz i Guildestern nie żyją. Nikt się tym nie przejmuje. Podobna reakcja mogłaby wystąpić wśród fizyków lub nawet historyków i filozofów nauki, gdyby ktoś zawiadomił, że Lummer i Pringsheim nie żyją.

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7 7 Kirchhoffs problem – 1860 G. Kirchhoff: Über das Verhältnis zwischen dem Emissionsvermögen und dem Absorptions- vermögen der Körper für Licht und Wärme, Annalen der Physik 19 (1860) 275.

8 8 Kirchhoffs black body definition: a(ν,T) = 1 Experimental problems: -radiation source -detector -method of spectral measurements G. Kirchhoff, Annalen der Physik 19 (1860) 275. When a space is surrounded by bodies of the same temperature, and no rays can penetrate through these bodies, every ray in the interior of the space is so constituted, with respect to its quality and intensity, as if it proceeded from a perfectly black body of the same temperature, and is therefore independent of the nature and form of the bodies, and only determined by the temperature.

9 9 Frederick William Herschel (1738-1822 ) 1800 – discovery of infrared radiation Radiant heat: in the search for u(ν,T)

10 10 F. W. Herschel, 1800: prism (glass) + thermometer J. H. Müller, 1859: rock salt prism + thermopile André P. P. Crova (1833- 1907) Light sources in order of increasing temperature: stearin candle, coal gas flame, electric arc light, sun Shift of the maximum with temperature John Tyndall (1820- 1893) J. Tyndall, 1864: rock salt prism + thermopile electric carbon arc light spectrum Refraction spectra redblue visible radiation invisible radiation

11 11 Thermo-electric pile (1860-s) bismuth antimony J. Tyndall, Heat considered as a mode of motion, 1864, Six lectures on light, 1872-3 "My assistant stands several feet off. I turn the thermopile towards him. The heat from his face, even at this distance, produces a deflection of 90 degrees [on the galvanometer dial]. I turn the instrument towards a distant wall, judged to be a little below the average temperature of the room. The needle descends and passes to the other side of zero, declaring by this negative deflection that the pile feels the chill of the wall."

12 12 J. Stefan (1879) + L. Boltzmann (1884) = Stefan-Boltzmann law Deduced by J. Stefan from J. Tyndalls experiments L. Boltzmann derived theoretically the law studying a heat engine with light as a working matter From weak red heat (about 525 C) to complete white heat (about 1200 C) the intensity of radiation increases from 10.4 to 122, thus nearly 12-fold (more precisely 11.7). The ratio of the absolute temperature 273 + 1200 and 273 + 525 raised to the fourth power gives 11.6. Stefan-Boltzmann law J. Stefan, Über die Beziehung zwischen der Wärmestrahlung und der Temperatur, Mathemat. –Naturwiss. Classe Abteilung 2 79 (1879), pp. 391–428.

13 13 Samuel P. Langleys bolometer - 1878 Langley's bolometer was so sensitive that it could detect thermal radiation from a cow a quarter of a mile away. Bolometer improved resistance thermometer 1880: T 10 -5 °C, ± 1% Two platinum strips, covered with lampblack, one strip was shielded from the radiation and one exposed to it. The strips formed two branches of a Wheatstone bridge which was fitted with a sensitive galvanometer and connected to a battery.

14 14 Bolometer in the service of photometry...we are facing a big problem, awaiting for solution. I mean the relationship between the temperature and radiation, as we do know virtually nothing about the issue, but once we know it, we will have a new view on almost all the processes occurring in nature. S. P. Langley, 1889 (S. Barr, Am. J. Phys. 28 (1960) 42) 0°C – 10 m 100 °C– 7.5 m Michelson equation (1887) described well Langleys results. W. Michelson, J. de Phys. 6 (1887) 467. In the derivation Michelson used Maxwells velocity distribution law.

15 15 Competition between electrical and gas lighting Platinum plate 1 cm 2 with T m Pt (2042 K) (1884) Platinum plate 1 cm 2 with T m Pt (2042 K) (1884) Hefner candle, standard in Germany (1883 – 1947) (amyl acetate, PTR) sensitive to fluctuations in air humidity Hefner candle, standard in Germany (1883 – 1947) (amyl acetate, PTR) sensitive to fluctuations in air humidity A search for reliable luminosity standard Carcel lamp, standard in France (rapeseed oil - 42 g/h) Carcel lamp, standard in France (rapeseed oil - 42 g/h) Light sources of that time (incandescent lamp [1879] of gas lamp radiated a lot of energy in the invisible part of the spectrum – radiometry must have been developed.

16 16 The place of birth of quantum physics: Physikalisch-Technische Reichsanstalt PTR Observatory (clock hall) and not the lecture room of the Physical Institute at Berlins University 1887 H. von Helmholtz

17 17 1898 Act on electrical units PTR, 1898 The Ohm is a unit of electrical resistance. It is equal to the resistance of a mercury column at a temperature of melting ice, with a length, at consistently identical cross section of 1 mm 2, of 106.3 cm, and a mass of 14,4521 gram. We Wilhelm, by the grace of God German Emperor, King of Prussia, etc. do order in the name of the German Empire…

18 18 Radiation Laboratory at PTR surface bolometer Lummer-Broduhn spectral bolometer

19 19 Development of detection techniques Lummers bolometr: T 10 -7 °C, ± 1% The purpose of optical studies is to confirm the fundamental laws of heat and light radiation. PTR Report 1899/1900:

20 20 Microstructural detectors (1890-s)

21 21 Ferdinand Kurlbaum 1857 - 1927 Heinrich Rubens 1865 - 1922 Otto Lummer 1860 - 1925 Ernst Pringsheim 1859 - 1917 Wilhelm Wien 1864 - 1928 Friedrich Paschen 1865 - 1947

22 22 J. Stefan (1879) + L. Boltzmann (1884) = Stefan-Boltzmann law W. Wien (1893) - Wien displacement law W. Wien (1896) - Wien law (until mid 1900 in agreement with experimental data) Stefan-Boltzmann law confirmed up to ± 1% (surface bolometer) Wien displacement law confirmed (linear bolometer) Radiation laws

23 23 Wien law - 1896 W. Wien, Annalen der Physik 58 (1896) 662.

24 24 Initially the importance of blackness of the bodies for emitted radiation was neglected. (man hat überhaupt außer acht gelassen) As black bodies blackened metal plates were used that can be used as black bodies only in a limited T range (Ch. Christiansen, 1880) Wien i Lummer (1895): we have to abandon these artificially blackened plates: (man muß überhaupt von den künstlich geschwärzten Blechen absehen und stattdessen die Strahlung eines schwarzen Körpers als den Zustand des Wärmegleichgewichts aufzufassen... Um hierauf auch eine praktisch brauchbare Methode zu gründen, durch die man die Strahlung eines schwarzen Körpers in beliebiger Annäherung herstellen kann, muss man einen Hohlraum auf gleichmässige Temperatur bringen und durch die Öffnung seine Strahlung nach aussen gelangen lassen.) W. Wien, O. Lummer, Annalen der Physik 56 (1895) 453. Should black body be black?

25 25 O. Lummer & E. Pringsheim: 1895 - 1898 liquid air boiling water boiling niter -188°C 100°C 680°C 1200°C hot gas Cavities: -cylindrical and spherical, metal -double-wall, spherical, porcelain -surface blackened with lampblack, FeO or UO 2 D. Hoffmann, On the Experimental Context of Plancks Foundation of Quantum Theory, 2000

26 26 Black body: platinum plate 0,01 mm 100 A / 1500°C graphite - 2100°C (1903) Electrically annealed black body (Lummer & Kurlbaum, 1898) W. Wien, O. Lummer, Annalen der Physik 56 (1895) 453. 40 cm 4 cm Lummer: professional blindness Lummer: Betriebsblindheit professional blindness

27 27 H. J. Kostkowski, R. D. Lee, Theory and methods of optical pyrometry, NBS Special Publication 300: Precision measurements and calibration. Temperature, Washington 1968, p. 361

28 28 Precision measurements of black body spectrum Tests of Wien energy distribution law (since 1899 - Wien-Planck e.d.l.) Spectrobolometer

29 29 Deviations from Wien distribution Feb. 1899: measurements up to 6 m, T: 800 - 1400°C indicate small deviations from Wien- Planck distribution O. Lummer, E. Pringsheim, Verh. Deutsch. Phys. Gesell. 1 (1899) 36.

30 30 Nov. 1899: measurements up to 8,3 m, T up to 1650°C: the discrepances between the theory and experiment are of systematic nature O. Lummer, E. Pringsheim, Verh. Deutsch. Phys. Gesell. 1 (1899) 226. Deviations from Wien distribution

31 31 Feb. 1900: in mesurements up to 18 m, T up to 1772°C: the differences between the theory and experiment reached 50% O. Lummer, E. Pringsheim, Verh. Deutsch. Phys. Gesell. 2 (1900) 163. Wien law is not generally valid, but … justified Feb. 1900: being aware of the above, Planck publishes justification of Wien law using a non-mechanistic, purely thermodynamic approach to the radiation field M. Planck Entropie und Temperatur strahlender Wärme, Annalen der Physik 1 (1900) 719.

32 32 Entropy and energy of a system of n resonators M. Planck Entropie und Temperatur strahlender Wärme, Annalen der Physik 1 (1900) 719.

33 33 Equations Planck (Oct. 19, 1900) Wien (PTR, 1896) Lummer & Pringsheim (PTR, Feb. 1900) Thiesen (PTR, Feb. 1900)

34 34 Reststrahlen-method: measurements up to 50 m. Clear divergences from Wien distribution. (die Abweichungen lassen sich nicht wegdiskutieren) H. Rubens i F. Kurlbaum, Oct. 1900 Deviations from Wien distribution

35 35 19 Oct. 1900

36 36 Wien Planck Planck, 19 Oct. 1900 U n, dU n and ΔU n are not sufficient to calculate dS n U is needed! Feb. 1900 M. Planck Über eine Verbesserung der Wienschen Spektralgleichung, Verh. Deutsch. Phys. Gesell. 2 (1900) 202.

37 37 «…at last I reached the point of constructing an absolutely arbitrary expressions for entropy which, though more complicated than the Wiens expression, seems to satisfy with the same perfection every requirement of the thermodynamic and electromagnetic theories.» Planck, 19 Oct. 1900 M. Planck Über eine Verbesserung der Wienschen Spektralgleichung, Verh. Deutsch. Phys. Gesell. 2 (1900) 202.

38 38 Planck, 14 Dec. 1900 M. Planck Zur Theorie des Gesetzes der Energieverteilung im Normalspectrum, Verh. Deutsch. Phys. Gesell. 2 (1900) 237. Discretization procedure

39 39 Es wäre erhebend, wenn wir die Gehirnsubstanz auf eine Waage legen könnten, die von den theoretischen Physikern auf dem Altar dieser universellen Funktion hingeopfert wurde; und es ist dieses grausamen Opfers kein Ende abzusehen! Noch mehr: auch die klassische Mechanik fiel ihr zu Opfer, und es ist nicht abzusehen, ob. Maxwells Gleichungen der Elektrodynamik die Krisis überdauern werden, welche diese Funktion f mit sich gebracht hat. A. Einstein, 1913

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