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Nobel Prize in Physics at IndonesiaNobel Fisika Indonesia
"Untuk membuat pencapaian moral yang tersirat dalam ilmu pengetahuan sebagi kekuatan peradaban. Ilmuwan harus bekerjasama dengan Filusuf dan Guru Agama"
~A. H. Compton~
"Saya Sesungguhnya Percaya bahwa dalam Kemajuan Ilmu Pengetahuan Terletak Harapan Peradaban Kita"
~C. T. R. Wilson~
The Nobel Prize in Physics 1927
"for his discovery of the effect named after him"
"for his method of making the paths of electrically charged particles visible by condensation of vapour"
 |  |
1/2 of the prize 1/2 of the prizeUSA
United Kingdom
University of Chicago
Chicago, IL, USA
University of Cambridge
Cambridge, United Kingdom
b. 1892
d. 1962
b. 1869
(in Glencorse, Scotland)
d. 1959
Titles, data and places given above refer to the time of the award.
Photos: Copyright © The Nobel Foundation
| Arthur Holly Compton | |
|---|---|
| Born | September 10, 1892 Wooster, Ohio, USA |
| Died | March 15, 1962 (aged 69) Berkeley, California, USA |
| Nationality | United States |
| Fields | Physics |
| Institutions | Washington University in St. Louis University of Chicago University of Minnesota Forman Christian College |
| Alma mater | College of Wooster Princeton University |
| Doctoral advisor | H. L. Cooke |
| Doctoral students | Winston H. Bostick Robert S. Shankland |
| Known for | Compton effect Compton length Compton scattering Compton wavelength Compton shift |
| Notable awards | Nobel Prize for Physics (1927) Franklin Medal (1940) |
Notes Compton is the son of Elias Compton, brother of Wilson Compton and Karl Taylor Compton, and father of John Joseph Compton. | |
Arthur Holly Compton (September 10, 1892 – March 15, 1962) was an American physicist and Nobel laureate in physics for his discovery of the Compton effect. He served as Chancellor of Washington University in St. Louis from 1945 to 1953.
Biography
Early years
Arthur Compton was born in Wooster, Ohio in 1892 to Elias and Otelia Compton. They were an academic family. His father Elias was dean of Wooster University (later The College of Wooster), which Arthur attended, and also became a member of the Alpha Tau Omega Fraternity. His eldest brother Karl also attended Wooster University, became a physicist, and was later president of MIT. His second brotherWilson Martindale Compton also attended Wooster University and became a diplomat and president of the State College of Washington, later Washington State University. All three brothers earned their Ph.D. degrees from Princeton University.[1]
Around 1913, Arthur Compton devised a demonstration method for the Earth's rotation. In 1918, he began studying X-ray scattering. In 1922, while on faculty at Washington University in St. Louis, Compton found that X-ray wavelengths increase due to scattering of the radiant energy by "free electrons". The scattered quanta have less energy than the quanta of the original ray. This discovery, known as the "Compton effect," or "Compton scattering" demonstrates the "particle" concept of electromagnetic radiation and earned Compton the Nobel Prize in physics in 1927. Compton developed the method for observing at the same instant individual scattered X-rayphotons and the recoil electrons (developed with Alfred W. Simon). In Germany, Walther Botheand Hans Geiger independently developed a similar method.
| C. T. R. Wilson | |
|---|---|
 The 1927 Solvay conference. | |
| Born | Charles Thomson Rees Wilson 14 February 1869 Midlothian, Scotland |
| Died | 15 November 1959 (aged 90) Edinburgh, Scotland |
| Nationality | Scottish |
| Fields | Physics |
| Institutions | University of Cambridge |
| Alma mater | University of Manchester University of Cambridge |
| Academic advisors | J. J. Thomson |
| Doctoral students | Cecil Frank Powell |
| Known for | Cloud chamber |
| Notable awards | Howard N. Potts Medal (1925) Nobel Prize in Physics 1927 Franklin Medal 1929 |
Charles Thomson Rees Wilson CH (14 February 1869 – 15 November 1959) was aScottish physicist and meteorologist who received the Nobel Prize in physics for his invention of the cloud chamber.
Biography
Wilson was born in the parish of Glencorse, Midlothian to a farmer, John Wilson, and his mother Annie Clerk Harper. After his father died in 1873, his family moved toManchester. He was educated at Owen's College, studying biology with the intent to become a physician. He then went to Sidney Sussex College, Cambridge where he became interested in physics and chemistry.[1]
Wilson thereafter became particularly interested in meteorology, and in 1893 he began to study clouds and their properties. He worked for some time at the observatory on Ben Nevis, where he made observations of cloud formation. He then tried to reproduce this effect on a smaller scale in the laboratory in Cambridge, expanding humid air within a sealed container. He later experimented with the creation of cloud trails in his chamber caused by ions and radiation. For the invention of the cloud chamber he received theNobel Prize in 1927.
Wilson married Jessie Fraser in 1908, the daughter of a minister from Glasgow, and the couple had four children. He died near Edinburgh, surrounded by his family.
Legacy
The Wilson Condensation Cloud formations, occurring after a very large explosion (such as a nuclear detonation), are named after him.
The Wilson Society, the natural sciences society of Sidney Sussex College, is also named for him.
The archives of Charles Thomson Rees Wilson are maintained by the Archives of the University of Glasgow (GUAS).
References
- ^ Wilson, Charles Thomson Rees in Venn, J. & J. A., Alumni Cantabrigienses, Cambridge University Press, 10 vols, 1922–1958.
- Asimov's Biographical Encyclopedia of Science and Technology, Isaac Asimov, 2nd ed., Doubleday & C., Inc., ISBN 0-385-17771-2.
Nobel Lecture
Nobel Lecture, December 12, 1927
X-rays as a Branch of Optics
From Nobel Lectures, Physics 1922-1941, Elsevier Publishing Company, Amsterdam, 1965
In order to read the text you need Acrobat Reader.
Nobel Lecture
Nobel Lecture, December 12, 1927
On the Cloud Method of Making Visible Ions and the Tracks of Ionizing Particles
From Nobel Lectures, Physics 1922-1941, Elsevier Publishing Company, Amsterdam, 1965
In order to read the text you need Acrobat Reader.
Presentation Speech
Presentation Speech by Professor K.M.G. Siegbahn, member of the Nobel Committee for Physics of the Royal Swedish Academy of Sciences, December 10, 1927
Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.
The Royal Academy of Sciences has awarded this year's Nobel Prize in Physics to Professor Arthur Holly Compton of the University of Chicago for the discovery of the phenomenon named after him the Compton effect, and to Professor Charles Thomson Rees Wilson of the University of Cambridge for his discovery of the expansion method of rendering visible the tracks of electrically charged particles.
Professor Compton has won his prize by work in the field of X-radiation. Soon after Röntgen's discovery it became known that matter exposed to X-rays emits radiations of different character. Besides an emission of electrons, corresponding to the photoelectric effect known also in the optical region of radiation, there is also a secondary X-radiation. Even before the methods of X-ray spectrometry were known, these secondary X-rays were proved by the investigation of their absorption to be of a twofold nature. It was Barkla who, through his fundamental researches, proved that the secondary X-radiation consists partly in a scattering of X-rays, which he thought to have the same penetrability as the original radiation, and partly in a specific X-radiation which was characteristic of the chemical atom and which was more easily absorbed.
When X-rays fell upon matter with small atomic weight, as for example graphite, Barkla was not able to detect the mentioned characteristic X-radiation, but only a scattering; and consequently the secondary rays ought to have the same properties as the original X-rays. Barkla, however, in the course of his investigations of the absorption, had already been able to show that in this case also the secondary X-rays - at least partly - are more easily absorbed than the original radiation and therefore have a greater wavelength. Barkla thought this to be a new characteristic X-radiation.
This is the point where Compton comes in and affects the development of science. He made exact spectrometrical investigations of the secondary X-radiation from matter with small atomic weight: in other words, he undertook to investigate exactly the scattered X-radiation. After some preliminary work, he found an experimental method that gave results which were as exact as they were astonishing.
Using homogeneous X-rays - corresponding optically to monochromatic illumination, that is to say, to the use of a source of light that emits only one single spectral line - he found that the scattered radiation consists of two lines, one exactly the same as that of the source of rays, the other with a somewhat greater wavelength. This is the first evident manifestation of the Compton effect. Its reality was at first disputed, but of late years it has been well established and verified.
The change in wavelength soon proved to be independent of the nature of the matter used for scattering, while it varies with the angle between the incident and the scattered rays. Hence the phenomenon cannot be explained as a new characteristic radiation of the same nature as that hitherto known; and Compton deduced a new kind of corpuscular theory, with which all experimental results showed perfect agreement within the limits of experimental error.
According to this theory, a quantum of radiation is re-emitted in a definite direction by a single electron, which in so doing must recoil in a direction forming an acute angle with that of the incident radiation. In its mathematical dress this theory leads to an augmentation of the wavelength that is independent of the wavelength of the incident radiation and implies a velocity of the recoil electron that varies between zero and about 80% of the velocity of light, when the angle between the incident and the scattered radiation varies between zero and 180°.
Thus this theory predicts recoil electrons with a velocity generally much smaller than that of the above-mentioned electrons which correspond to the photoelectric effect. It was a triumph for both parties when these recoil electrons were discovered by Wilson's experimental method both by Wilson himself and, independently, by another investigator. Hereby the second chief phenomenon of the Compton effect was experimentally verified, and all observations proved to agree with what had been predicted in Compton's theory.
Quite apart from the improvements and additions that have been made to this theory by other investigators, the Compton effect has, through the latest evolutions of the atomic theory, got rid of the original explanation based upon a corpuscular theory. The new wave mechanics, in fact, lead as a logical consequence to the mathematical basis of Compton's theory. Thus the effect has gained an acceptable connection with other observations in the sphere of radiation. It is now so important that, in the future, no atomic theory can be accepted that does not explain it and lead to the laws established by its discoverer.
Finally, the fact deserves to be emphasized that the Compton effect has proved to be of decisive influence upon the absorption of short-wave electromagnetic - especially radioactive - radiation and of the newly discovered cosmic rays.
The Royal Academy of Sciences has awarded this year's Nobel Prize in Physics to Professor Arthur Holly Compton of the University of Chicago for the discovery of the phenomenon named after him the Compton effect, and to Professor Charles Thomson Rees Wilson of the University of Cambridge for his discovery of the expansion method of rendering visible the tracks of electrically charged particles.
Professor Compton has won his prize by work in the field of X-radiation. Soon after Röntgen's discovery it became known that matter exposed to X-rays emits radiations of different character. Besides an emission of electrons, corresponding to the photoelectric effect known also in the optical region of radiation, there is also a secondary X-radiation. Even before the methods of X-ray spectrometry were known, these secondary X-rays were proved by the investigation of their absorption to be of a twofold nature. It was Barkla who, through his fundamental researches, proved that the secondary X-radiation consists partly in a scattering of X-rays, which he thought to have the same penetrability as the original radiation, and partly in a specific X-radiation which was characteristic of the chemical atom and which was more easily absorbed.
When X-rays fell upon matter with small atomic weight, as for example graphite, Barkla was not able to detect the mentioned characteristic X-radiation, but only a scattering; and consequently the secondary rays ought to have the same properties as the original X-rays. Barkla, however, in the course of his investigations of the absorption, had already been able to show that in this case also the secondary X-rays - at least partly - are more easily absorbed than the original radiation and therefore have a greater wavelength. Barkla thought this to be a new characteristic X-radiation.
This is the point where Compton comes in and affects the development of science. He made exact spectrometrical investigations of the secondary X-radiation from matter with small atomic weight: in other words, he undertook to investigate exactly the scattered X-radiation. After some preliminary work, he found an experimental method that gave results which were as exact as they were astonishing.
Using homogeneous X-rays - corresponding optically to monochromatic illumination, that is to say, to the use of a source of light that emits only one single spectral line - he found that the scattered radiation consists of two lines, one exactly the same as that of the source of rays, the other with a somewhat greater wavelength. This is the first evident manifestation of the Compton effect. Its reality was at first disputed, but of late years it has been well established and verified.
The change in wavelength soon proved to be independent of the nature of the matter used for scattering, while it varies with the angle between the incident and the scattered rays. Hence the phenomenon cannot be explained as a new characteristic radiation of the same nature as that hitherto known; and Compton deduced a new kind of corpuscular theory, with which all experimental results showed perfect agreement within the limits of experimental error.
According to this theory, a quantum of radiation is re-emitted in a definite direction by a single electron, which in so doing must recoil in a direction forming an acute angle with that of the incident radiation. In its mathematical dress this theory leads to an augmentation of the wavelength that is independent of the wavelength of the incident radiation and implies a velocity of the recoil electron that varies between zero and about 80% of the velocity of light, when the angle between the incident and the scattered radiation varies between zero and 180°.
Thus this theory predicts recoil electrons with a velocity generally much smaller than that of the above-mentioned electrons which correspond to the photoelectric effect. It was a triumph for both parties when these recoil electrons were discovered by Wilson's experimental method both by Wilson himself and, independently, by another investigator. Hereby the second chief phenomenon of the Compton effect was experimentally verified, and all observations proved to agree with what had been predicted in Compton's theory.
Quite apart from the improvements and additions that have been made to this theory by other investigators, the Compton effect has, through the latest evolutions of the atomic theory, got rid of the original explanation based upon a corpuscular theory. The new wave mechanics, in fact, lead as a logical consequence to the mathematical basis of Compton's theory. Thus the effect has gained an acceptable connection with other observations in the sphere of radiation. It is now so important that, in the future, no atomic theory can be accepted that does not explain it and lead to the laws established by its discoverer.
Finally, the fact deserves to be emphasized that the Compton effect has proved to be of decisive influence upon the absorption of short-wave electromagnetic - especially radioactive - radiation and of the newly discovered cosmic rays.
Professor Compton. Your discovery of the phenomenon known as the Compton effect has already proved so important that the Royal Academy of Sciences has awarded you a Nobel Prize, which I now ask you to receive from the hands of His Majesty.
Professor Wilson has been awarded his prize for the discovery of a purely experimental method, which dates back from as long ago as 1911. It is based upon the formation of clouds, which develop when sufficiently moist air is suddenly expanded. The refrigeration caused by the expansion brings the temperature to sink below the dew-point, and the vapour is condensed into small drops, which form together visible clouds. In the first stage of condensation a droplet is always formed round a nucleus. The fact that an electrically charged particle acts as a nucleus in the formation of drops could, after the discovery of the corpuscular radiations, be concluded from an experiment that Helmholtz had, long before, made when he found that a stream of vapour loses its transparency in the vicinity of electrically charged objects.
After it had become known that electricity is conducted through gases by means of ions, and that ions are formed - or, in other words, gases are ionized - under the influence of X-rays or radioactive substances, the way lay open for Wilson to follow photographically the formation of droplets around electrically charged particles. Alpha and beta particles emitted by radioactive substances ionize the gases, and their tracks are marked by a formation of droplets. A suitable photograph of these droplets then gives a picture of the tracks of the ionizing particles.
The problem is a little more complicated when the nature and the details of the ionization caused by X-rays have to be analysed; and the perfect method for such investigations was not described until in a paper of 1923. The extremely delicate regulation of small-time intervals which is necessary in such researches is attained by the use of three pendulums of adjustable period, which are all released simultaneously. The pendulum which comes down first, opens a communication with a vacuum, and the resulting suction is used, by a mechanical device, to produce a sudden expansion of the gas that is being examined. The second pendulum releases an electric spark, which passes through an X-ray tube, oscillatory sparks being excluded; and thus the anticathode is brought to send an X-radiation of extremely short duration through the gas before the lenses of a stereoscopic camera. The third pendulum releases another electric spark, which passes through mercury vapour and momentarily illuminates the clouds. By means of sliding weights on the different pendulums, just as on an ordinary metronome, Wilson was able to bring it about that the X-rays were sent through the gas at the moment when the expansion was complete, and the illuminating spark just as long afterwards as was needed for a sufficient formation of droplets round the ions, but before the droplets had time to be dislocated by currents in the gas, which might have deformed the tracks visible on the photographic pictures.
Wilson's method attracted attention at first mainly as an elegant and popular method of demonstration. The formation of droplets by x-particles is so dense that the resulting cloud photographs show continuous white lines: and everybody was glad to recognize on these lines the sharp bendings which correspond to the sudden change of direction previously known. Along the beta-rays, on the other hand, are seen isolated droplets, and their tracks show a multitude of different types according to differences in initial velocity. For the investigation of such rays with a comparatively small velocity, the most suitable method is the excitation by the momentary X-radiation described above. Here there has been collected a very large photographic material, from which probably not all possible conclusions have yet been drawn, and to which Wilson has devoted assiduous work.
Of late years, new and scientifically important results have been attained which could not have been gained by other methods. The consequence of this is that the discovery, although it was made so long ago, satisfies the provisions for the award of the Nobel Prize. It would not be of much use to describe these results on this occasion, as the understanding of them presupposes full knowledge of the structure of the atom. I will merely call to mind that in 1923 Wilson gave the experimental proof of the existence of the recoil electron tracks that had been postulated by Compton for his explanation of the change in wavelength of scattered X-rays, and that his method has rendered possible the closer examination of these tracks.
Professor Wilson has been awarded his prize for the discovery of a purely experimental method, which dates back from as long ago as 1911. It is based upon the formation of clouds, which develop when sufficiently moist air is suddenly expanded. The refrigeration caused by the expansion brings the temperature to sink below the dew-point, and the vapour is condensed into small drops, which form together visible clouds. In the first stage of condensation a droplet is always formed round a nucleus. The fact that an electrically charged particle acts as a nucleus in the formation of drops could, after the discovery of the corpuscular radiations, be concluded from an experiment that Helmholtz had, long before, made when he found that a stream of vapour loses its transparency in the vicinity of electrically charged objects.
After it had become known that electricity is conducted through gases by means of ions, and that ions are formed - or, in other words, gases are ionized - under the influence of X-rays or radioactive substances, the way lay open for Wilson to follow photographically the formation of droplets around electrically charged particles. Alpha and beta particles emitted by radioactive substances ionize the gases, and their tracks are marked by a formation of droplets. A suitable photograph of these droplets then gives a picture of the tracks of the ionizing particles.
The problem is a little more complicated when the nature and the details of the ionization caused by X-rays have to be analysed; and the perfect method for such investigations was not described until in a paper of 1923. The extremely delicate regulation of small-time intervals which is necessary in such researches is attained by the use of three pendulums of adjustable period, which are all released simultaneously. The pendulum which comes down first, opens a communication with a vacuum, and the resulting suction is used, by a mechanical device, to produce a sudden expansion of the gas that is being examined. The second pendulum releases an electric spark, which passes through an X-ray tube, oscillatory sparks being excluded; and thus the anticathode is brought to send an X-radiation of extremely short duration through the gas before the lenses of a stereoscopic camera. The third pendulum releases another electric spark, which passes through mercury vapour and momentarily illuminates the clouds. By means of sliding weights on the different pendulums, just as on an ordinary metronome, Wilson was able to bring it about that the X-rays were sent through the gas at the moment when the expansion was complete, and the illuminating spark just as long afterwards as was needed for a sufficient formation of droplets round the ions, but before the droplets had time to be dislocated by currents in the gas, which might have deformed the tracks visible on the photographic pictures.
Wilson's method attracted attention at first mainly as an elegant and popular method of demonstration. The formation of droplets by x-particles is so dense that the resulting cloud photographs show continuous white lines: and everybody was glad to recognize on these lines the sharp bendings which correspond to the sudden change of direction previously known. Along the beta-rays, on the other hand, are seen isolated droplets, and their tracks show a multitude of different types according to differences in initial velocity. For the investigation of such rays with a comparatively small velocity, the most suitable method is the excitation by the momentary X-radiation described above. Here there has been collected a very large photographic material, from which probably not all possible conclusions have yet been drawn, and to which Wilson has devoted assiduous work.
Of late years, new and scientifically important results have been attained which could not have been gained by other methods. The consequence of this is that the discovery, although it was made so long ago, satisfies the provisions for the award of the Nobel Prize. It would not be of much use to describe these results on this occasion, as the understanding of them presupposes full knowledge of the structure of the atom. I will merely call to mind that in 1923 Wilson gave the experimental proof of the existence of the recoil electron tracks that had been postulated by Compton for his explanation of the change in wavelength of scattered X-rays, and that his method has rendered possible the closer examination of these tracks.
Professor Wilson. Although a long time has elapsed since you discovered your elegant expansion method, the high value of your discovery has been greatly augmented both through your own assiduous investigations and through results obtained by others. The Academy is happy that an article in the Statutes allows it in such cases to reward even discoveries of comparatively old date; and I now ask you to receive the prize that you have won from the hands of His Majesty.
From Nobel Lectures, Physics 1922-1941, Elsevier Publishing Company, Amsterdam, 1965
Copyright © The Nobel Foundation 1927
Sumber:
1. Wikipedia
2. Nobel Prize Org.
Ucapan Terima Kasih:
Ucapan Terima Kasih:
1. DEPDIKNAS Republik Indonesia
2. Kementrian Riset dan Teknologi Indonesia
3. Lembaga Ilmu Pengetahuan Indonesia (LIPI)
4. Akademi Ilmu Pengetahuan Indonesia
5. Tim Olimpiade Fisika Indonesia
Disusun Ulang Oleh:
Arip Nurahman
Pendidikan Fisika, FPMIPA, Universitas Pendidikan Indonesia
&
Follower Open Course Ware at MIT-Harvard University, USA.
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