Hermann von Helmholtz
Hermann von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz
August 31, 1821
|September 8, 1894
|Physicist and physiologist
|University of Königsberg
University of Bonn
University of Heidelberg
University of Berlin
|Royal Friedrich-Wilhelm Institute
|Johannes Peter Müller
|Albert Abraham Michelson
|Conservation of energy
Hermann Ludwig Ferdinand von Helmholtz (August 31, 1821 – September 8, 1894) was a German physician and physicist. He contributed to many fields, including physiology, fluid dynamics, the theory of electricity and magnetism, and thermodynamics. His formulation of the principle of conservation of energy influenced a generation of physicists. He invented the ophthalmoscope, which revolutionized the field of ophthalmology; and he invented a resonator to show the strength of various tones. In his philosophy of physiology, he emphasized experience as important for the formation of perception, although he did not altogether deny pre-existing and innate categories of perception.
Helmholtz was the son of the Potsdam Gymnasium headmaster, Ferdinand Helmholtz, who had studied classical philology and philosophy, and who was a close friend of the publisher and philosopher Immanuel Hermann Fichte. Helmholtz's mother, Caroline Penn, was of English extraction.
As a young man, Helmholtz did not distinguish himself in his early studies, but showed a proficiency in math and science. At age 17, he expressed an interest in physics, but economic circumstances dictated his career direction as a military doctor. He studied at the medico-surgical institute in Berlin from 1838 to 1842, where he earned his degree upon acceptance of his dissertation on the nerve cells of ganglia. He remained in that city and practiced as an army surgeon, all the while continuing his studies in physics and mathematics in his spare time.
Conservation of energy
His first important scientific achievement, an 1847 physics treatise on the conservation of energy, was written in the context of his medical studies and philosophical background. He discovered the principle of conservation of energy while studying muscle metabolism. He tried to demonstrate that no energy is lost in muscle movement, motivated by the implication that there were no vital forces necessary to move a muscle.
Drawing on the earlier work of Sadi Carnot, Émile Clapeyron and James Prescott Joule, he postulated a relationship between mechanics, heat, light, electricity and magnetism by treating them all as manifestations of a single force (energy in modern terms). He published his theories in his book Über die Erhaltung der Kraft (On the Conservation of Force, 1847).
In 1848, Helmholtz became assistant of the Anatomical Museum in Berlin, and teacher of anatomy at the Academy of Arts. A year later he moved to Konigsberg to assume a professorship in physiology, where he spent the next seven years. In 1849, Helmholtz married Olga von Velten.
In 1851, Helmholtz revolutionized the field of ophthalmology with the invention of the ophthalmoscope; an instrument used to examine the inside of the human eye. This made him world famous overnight. Helmholtz's interests at that time were increasingly focused on the physiology of the senses. His main publication, entitled Handbuch der Physiologischen Optik (Handbook of Physiological Optics), provided empirical theories on spatial vision, color vision, and motion perception, and became the fundamental reference work in this field during the second half of the nineteenth century. His theory of accommodation went unchallenged until the final decade of the twentieth century.
Helmholtz became professor of anatomy and physiology at the University of Bonn in 1856. He developed an interest in fluid dynamics and showed that movement such as that illustrated by a smoke ring would, in a frictionless fluid, continue forever. This result was expanded upon by William Thomson, who entertained the hypothesis that such rings were the basis for the existence of atoms.
In 1859, Helmholtz's first wife Olga died after a long illness. They had two children. In 1859, he took a position as professor of physiology at the University of Heidelberg. In 1861, Helmholtz married again, this time to Anna von Mohl; the couple had two children.
In 1863, Helmholtz published a book called On the Sensations of Tone as a Physiological Basis for the Theory of Music, once again demonstrating his interest in the physics of perception. This book influenced musicologists into the twentieth century. Helmholtz invented the Helmholtz resonator to show the strength of the various tones.
In 1871, Helmholtz moved from Heidelberg to the University of Berlin where he became a professor of natural philosophy, finally fulfilling his lifelong dream of a career in physics. There he took up some of the problems of electromagnetic theory. His mathematical formulation in this field is known as Helmholtz's equation. Helholtz's student Heinrich Rudolf Hertz became famous as the first to experimentally demonstrate the existence of electromagnetic radiation, as predicted by the work of James Clerk Maxwell. Hertz's discoveries were a direct result of a challenge made to him by Helmholtz to demonstrate the existence of what Maxwell had called the displacement current in air and in empty space.
In 1883 Helmholtz introduced the concept of free energy, the heat energy available to do work. This was an important advance in thermodynamics, and the concept is widely used in the subject as it is taught today.
In 1887, in addition to his teaching duties in Berlin, he became director of the physicotechnical institute in Charlottenburg. His last years were devoted to an attempt to unify the sciences under the principle of least action.
Helmholtz continued to work for several decades on editions of the Handbook of Physiological Optics, frequently updating his work because of his dispute with Ewald Hering who held opposite views on spatial and color vision. Helmholtz tended to rely on experience as an important input to spatial comprehension, while Hering and the so-called "nativists" emphasized the innate intuition as playing the most important role. The philosophical dispute divided the discipline of physiology during the second half of the 1800s.
Students and associates
Students and research associates of Helmholtz at Berlin included Max Planck, Heinrich Kayser, Eugen Goldstein, Wilhelm Wien, Arthur König, Henry Augustus Rowland, A. A. Michelson, and Michael Pupin. Leo Koenigsberger, who studied at Berlin while Helmholtz was there, wrote the definitive biography of Helmholtz in 1902.
The sensory physiology of Helmholtz was the basis of the work of Wilhelm Wundt, a student of Helmholtz, who is considered one of the founders of experimental psychology. He, more explicitly than Helmholtz, described his research as a form of empirical philosophy and as a study of the mind as something separate. Helmholtz had, in his early critique of the speculative early nineteenth century tradition of Naturphilosophie, stressed the importance of materialism, and was focusing more on the unity of "mind" and body.
Helmholtz extended a theory originally proposed by Thomas Young that the human eye detects and is sensitive to only three primary colors. Helmholtz proposed that each of these three colors has a particular type of receptor in the eye that detects it.
Helmholtz's treatise on the principle of the conservation of energy was widely read and, in spite of his medical background, influenced a generation of physicists who were trying to decipher the mechanism of heat and its transformations. Helmholtz continued to make major contributions to fields as diverse as physiology, applied mathematics, electromagnetic theory, and thermodynamics. His work, particularly in the philosophy and physiology of perception, continued to exert an influence on scientists through the twentieth century. Of his contribution to hydrodynamics (fluid flow), James Clerk Maxwell said: "...he establishes principles...which have escaped the penetrative power of all the mathematicians who preceded him, including (Joseph Louis) Lagrange himself" (Maxwell, 2003).
Helmholtz put great stock in the importance of meeting the best minds of his time. "When one finds himself in contact with a man of the first order," Helmholtz wrote, "the entire scale of one's intellectual conceptions is modified for life. Contact with such a man is perhaps the most interesting thing life may have to offer" (Maxwell, 2003).
- The usage of terms such as work, force, energy, and power in the eighteenth and nineteenth centuries by scientific workers does not necessarily reflect the standardized modern usage.
ReferencesISBN links support NWE through referral fees
- Cahan, David. 1993. Hermann von Helmholtz and the Foundations of Nineteenth-Century Science. Berkeley: University of California Press.
- Koenigsberger, Leo. 1906. Hermann von Helmholtz. Tr. Frances Alice Welby. Oxford: Clarendon Press.
- Maxwell, James Clerk. 2003. Hermann Ludwig Ferdinand Helmholtz. In The Scientific Papers of James Clerk Maxwell. Mineola, NY: Dover Publications. 1:293, 2:597,753. ISBN 0486495604
All links retrieved December 22, 2017.
- O'Connor, John J.; Edmund F. Robertson "Hermann von Helmholtz". MacTutor History of Mathematics archive.
- On the Conservation of Force Introduction to a Series of Lectures Delivered at Carlsruhe in the Winter of 1862–1863, English translation.
- Biography and bibliography in the Virtual Laboratory of the Max Planck Institute for the History of Science.
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Hermann von Helmholtz (Aagosti 31, 1821 - Septemba 8, 1894 - Jimbo la Königsberg, Ujerumani) alikuwa mwanafizikia na mwanasayansi wa Ujerumani. Alitoa mchango katika nyanja nyingi, kutia ndani fizikia, mienendo ya umajimaji, nadharia ya umeme na sumaku, na termodynamics. Maelezo yake kuhusu kanuni ya kuhifadhi nishati yaliathiri kizazi cha wanasayansi. Alianzisha kifaa cha kupima macho (Ophthalmoscope) ambacho kilibadili sana matibabu ya macho, na pia kifaa cha kupima sauti (resonator) ambacho kilionyesha nguvu za sauti mbalimbali. Katika falsafa yake ya fizikia, alisisitiza uzoefu kama muhimu kwa malezi ya utambuzi, ingawa hakuwa kabisa kukataa kabla ya kuwepo na asili makundi ya utambuzi. Helmholtz alikuwa mwana wa mkuu wa shule ya Potsdam Gymnasium, Ferdinand Helmholtz, ambaye alikuwa amesoma filolojia ya kale na falsafa, na ambaye alikuwa rafiki wa karibu wa mchapishaji na mwanafalsafa Immanuel Hermann Fichte. Mama ya Helmholtz, Caroline Penn, alikuwa wa asili ya Uingereza. Alipokuwa kijana, Helmholtz hakujitambulisha katika masomo yake ya mapema, lakini alionyesha ustadi katika hisabati na sayansi. Alipokuwa na umri wa miaka 17, alionyesha kupendezwa na fizikia, lakini hali za kiuchumi zilimfanya afanye kazi ya kuwa daktari wa kijeshi. Alipata elimu katika Taasisi ya Upasuaji ya Berlin, ambapo alipata shahada ya kwanza baada ya kuhitimu kwa ajili ya dissertation yake juu ya seli za neva za ganglia. Alikaa huko na kufanya kazi kama daktari wa upasuaji wa jeshi, huku akiendelea na masomo yake ya fizikia na hisabati wakati wake wa kupumzika. "Kutengeneza ""Uhifadhi wa Nishati"" ni kazi yake ya kwanza ya kisayansi ya 1847 iliyoandikwa katika mazingira ya masomo yake ya matibabu na falsafa." Aligundua kanuni ya kuhifadhi nishati alipokuwa akichunguza kimetaboliki ya misuli. Alijaribu kuonyesha kwamba hakuna nishati inayopotea katika mwendo wa misuli, akichochewa na maana ya kwamba hakukuwa na nguvu muhimu za kuhamisha misuli. Kwa kutegemea kazi ya awali ya Sadi Carnot, Émile Claperon na James Prescott-Joule, alidai uhusiano kati ya mitambo, joto, mwanga, umeme na sumaku kwa kuwatendea wote kama maonyesho ya nguvu moja (nishati katika maneno ya kisasa). Alitoa nadharia zake katika kitabu chake Über die Erhaltung der Kraft (Kuhusu Uhifadhi wa Nguvu, 1847). Mwaka 1848 Helmholtz alijiunga na Chuo cha Sanaa cha Berlin na kuwa mwalimu wa anatomia. Mwaka mmoja baadaye alihamia Konigsberg kuchukua profesa katika physiology, ambapo alitumia miaka saba ijayo. Mwaka 1849 Helmholtz aliolewa na Olga von Velten. Mwaka 1851 Helmholtz alibuni kifaa cha kuchunguza macho. Jambo hilo lilimfanya awe mashuhuri ulimwenguni pote kwa usiku mmoja. Wakati huo, Helmholtz alipendezwa zaidi na fizikia ya hisi. Kitabu chake cha kwanza, Handbuch der Physiologischen Optik, kilikuwa na masomo ya kuona kwa nafasi, kuona rangi, na kuona mwendo, na kilikuwa kitabu muhimu sana katika sehemu hiyo ya karne ya 19. Nadharia yake ya makazi haikupingwa hadi mwongo wa mwisho wa karne ya ishirini. Helmholtz alikuwa profesa wa anatomia na fizikia katika Chuo Kikuu cha Bonn. Alipendezwa na nguvu za umajimaji na akaonyesha kwamba mwendo kama ule unaoonyeshwa na pete ya moshi, katika umajimaji usio na msuguano, ungeendelea milele. Matokeo hayo yaliendelezwa na William Thomson, ambaye alitoa nadharia ya kwamba pete hizo ndizo msingi wa kuwepo kwa atomu. Mwaka 1859 mke wa kwanza wa Helmholtz, Olga, alikufa baada ya kuugua kwa muda mrefu. Walikuwa na watoto wawili. Mwaka 1859 alianza kazi ya ualimu katika Chuo Kikuu cha Heidelberg. Mnamo 1861, Helmholtz aliolewa tena, wakati huu na Anna von Mohl; wenzi hao walikuwa na watoto wawili. "Helmholtz aliandika kitabu chake cha ""On the Sensations of Tone as a Physiological Basis for the Theory of Music"" mwaka 1863 na kuelezea jinsi muziki ulivyo na athari kubwa katika maisha ya watu." Kitabu hicho kiliwaathiri wasomi wa muziki katika karne ya ishirini. Helmholtz alivumbua kipima-sauti cha Helmholtz ili kuonyesha nguvu ya sauti mbalimbali. Mwaka 1871 Helmholtz alihamia Chuo Kikuu cha Berlin, ambapo akawa profesa wa falsafa ya asili, hatimaye kutimiza ndoto yake ya maisha ya kazi katika fizikia. Akiwa huko alichukua baadhi ya matatizo ya nadharia ya sumaku-umeme. Fomula yake ya hisabati katika uwanja huu inajulikana kama equation ya Helmholtz. Mwanafunzi wa Helholtz, Heinrich Rudolf Hertz, alikuwa mtu wa kwanza kuonyesha kwa majaribio kuwapo kwa mnururisho wa umeme, kama ilivyotabiriwa na James Clerk Maxwell. "Hertz alishindwa na Helmholtz kwa sababu ya ""mzunguko wa kuhamisha"" (displacement current) katika hewa na nafasi tupu." Mwaka 1883 Helmholtz alianzisha dhana ya nishati ya bure, ambayo ni nishati ya joto inayopatikana kufanya kazi. Hii ilikuwa maendeleo muhimu katika thermodynamics, na dhana ni sana kutumika katika somo kama ni kufundishwa leo. Mwaka 1887 alihitimu kazi ya ualimu katika chuo cha Charlottenburg. Miaka yake ya mwisho ilitumiwa kujaribu kuunganisha sayansi chini ya kanuni ya hatua ndogo zaidi. Helmholtz aliendelea kufanya kazi kwa miongo kadhaa kwenye toleo la Handbook of Physiological Optics, mara kwa mara akiboresha kazi yake kwa sababu ya mzozo wake na Ewald Hering ambaye alikuwa na maoni tofauti juu ya maono ya nafasi na rangi. Helmholtz alikuwa na mwelekeo wa kutegemea uzoefu kama mchango muhimu kwa uelewa wa nafasi, wakati Hering na wanaojulikana kama "nativists" walikazia intuition ya asili kama kucheza jukumu muhimu zaidi. Mjadala wa kifalsafa uliigawanya taaluma ya fizikia wakati wa nusu ya pili ya miaka ya 1800. Katika miaka ya mwisho ya miaka ya 1800, Helmholtz alishirikiana na wataalamu wa sayansi na sayansi kama vile Max Planck, Heinrich Kayser, Eugen Goldstein, Wilhelm Wien, Arthur König, Henry Augustus Rowland, na wengineo. A. Michelson, na Michael Pupin. Leo Koenigsberger, ambaye alisoma huko Berlin wakati Helmholtz alipokuwa huko, aliandika wasifu wa mwisho wa Helmholtz mnamo 1902. "Helmshoft alikuwa mwanafunzi wa Wilhelm Wundt, ambaye anajulikana kama ""mwanzilishi wa saikolojia ya majaribio.""" "Helmshoft alitoa maoni yake ya kwanza kuhusu ""fasihi ya kihistoria"" na ""ufahamu wa akili.""" Helmholtz alikuwa, katika ukosoaji wake wa mapema wa mapendekezo ya karne ya kumi na tisa ya asili ya Naturphilosophie, alisisitiza umuhimu wa materialism, na alikuwa akizingatia zaidi umoja wa "akili" na mwili. Helmholtz aliendeleza nadharia iliyopendekezwa awali na Thomas Young kwamba jicho la binadamu huona na huelewa rangi tatu tu za msingi. Helmholtz alipendekeza kwamba kila moja ya rangi hizi tatu ina aina fulani ya kipokeaji katika jicho ambacho huigundua. Kitabu cha Helmholtz kuhusu kanuni ya kuhifadhi nishati kilisomwa sana na, licha ya elimu yake ya kitiba, kiliathiri kizazi cha wanasayansi ambao walikuwa wakijaribu kufunua utaratibu wa joto na mabadiliko yake. Helmholtz aliendelea kuchangia sana katika nyanja mbalimbali kama vile fizikia, hisabati, nadharia ya sumaku-umeme, na termodynamics. Kazi yake, hasa katika falsafa na fizikia ya utambuzi, iliendelea kuwa na uvutano juu ya wanasayansi katika karne ya ishirini. "Kuhusu mchango wake katika hydrodynamics, James Clerk Maxwell alisema: ""Ameanzisha kanuni ambazo zimeponyoka nguvu ya kupenya ya wanahisabati wote waliomtangulia, ikiwa ni pamoja na Joseph Louis Lagrange mwenyewe.""" Helmholtz aliona umuhimu wa kukutana na akili bora za wakati wake. "Huenda mtu akijikuta akishirikiana na mtu wa hali ya juu,"" akaandika Helmholtz, ""mtazamo wote wa akili ya mtu hubadilishwa kwa maisha yake yote." "Kutembelea mtu kama huyo labda ni jambo la kupendeza zaidi ambalo maisha yanaweza kutoa. """ - Matumizi ya maneno kama vile kazi, nguvu, nishati, na nguvu katika karne ya kumi na nane na kumi na tisa na wafanyakazi wa kisayansi si lazima kuonyesha matumizi ya kisasa ya kawaida. Msaada wa NBN kwa NWE kupitia ada ya rufaa - Cahan, David Mwaka 1993 Hermann von Helmholtz na Misingi ya Sayansi ya Karne ya Kumi na Tisa. Berkeley: Chuo Kikuu cha California Press. - Koenigsberger, Leo. Mwaka 1906 Hermann von Helmholtz, mwandishi wa habari. Tr. Alice Frances Welby Oxford: Clarendon Press. (Kampuni ya kuchapisha ya Oxford) - Maxwell, James Clerk. Mwaka 2003 Hermann Ludwig Ferdinand Helmholtz (Mwandishi wa Ujerumani) Katika The Scientific Papers of James Clerk Maxwell. Mineola, NY: Dover Machapisho. 1:29-32, 2:59-57, 753 - Ni nini kilichotokea? ISBN: 0484495604 (Kifungo cha kwanza kilichopatikana Desemba 22, 2017) - O'Connor, John J.; Edmund F. Robertson "Hermann von Helmholtz". MacTutor Historia ya Hisabati kumbukumbu. "Kutoka kwa ""Uhifadhi wa Nguvu"" katika Mfululizo wa Hotuba zilizotolewa katika Carlsruhe katika Majira ya baridi ya 1862-1863, tafsiri ya Kiingereza." - Biografia na bibliografia katika Maabara Virtual ya Taasisi ya Max Planck kwa Historia ya Sayansi. Waandishi na wahariri wa New World Encyclopedia waliandika upya na kukamilisha makala ya Wikipedia kulingana na viwango vya New World Encyclopedia. Makala hii inatii masharti ya Creative Commons CC BY-SA 3.0 Leseni (CC BY-SA), ambayo inaweza kutumika na kusambazwa na sifa sahihi. Mikopo inapaswa chini ya masharti ya leseni hii ambayo inaweza kurejelea wote New World Encyclopedia wachangiaji na kujitolea kujitolea wachangiaji wa Wikimedia Foundation. "Kwa mfano, ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala hii ni ""Mfano wa makala."""