View source for Philipp Lenard

{{Short description|Hungarian–German experimental physicist (1862–1947)}}
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{{Infobox scientist
| name              = Philipp Lenard
| image             = Lenard.jpg
| caption           = Lenard in 1905
| birth_name        = Philipp Eduard Anton von Lenard
| birth_date        = {{Birth date|1862|06|07|df=yes}}
| birth_place       = <!-- Per birth_place in Template:infobox person -->[[Bratislava|Pressburg]], [[Kingdom of Hungary (1526–1867)|Kingdom of Hungary]], [[Austrian Empire]]
| death_date        = {{Death date and age|1947|05|20|1862|06|07|df=yes}}
| death_place       = [[Messelhausen]], [[American occupation zone in Germany|US-Zone]], [[Allied-occupied Germany]]
| alma_mater        = [[University of Heidelberg]] ([[Dr. phil.]])
| known_for         = {{Plain list|
* [[Cathode ray]]s
* [[Photoelectric effect]]
}}
| movement          = {{Lang|de|[[Deutsche Physik]]}}
| awards            = {{Plain list|
* [[Rumford Medal]] (1896)
* [[Matteucci Medal]] (1896)
* [[Nobel Prize in Physics]] (1905)
* [[Franklin Medal]] (1932)
}}
| field             = [[Particle physics]]
| work_institutions = {{Plain list|
* [[University of Kiel]] <br/> (1898–1907)
* University of Heidelberg (1907–1931)
}}
| thesis_title      = Über die Schwingung fallender Tropfen
| thesis_url        = https://bonnus.ulb.uni-bonn.de/discovery/fulldisplay?vid=49HBZ_ULB:DEFAULT&docid=alma991020676979706467&context=L
| thesis_year       = 1886
| doctoral_advisor  = [[Georg Quincke]]
| academic_advisors = [[Robert Bunsen]]
| doctoral_students = {{Plain list|
* [[Edward Andrade]] (1911)<ref name=PhysicsTree>{{Cite web|title=Philipp Eduard Anton Lenard - Physics Tree|url=https://academictree.org/physics/peopleinfo.php?pid=73638|website=academictree.org|access-date=2025-07-15}}</ref><!--<ref>{{cite book |author-last=Andrade|author-first=E.N. da C. |editor-last= Ewald|editor-first=  P.P.|editor-link=Paul Peter Ewald|date= July 1962|title= 50 Years of X-ray crystallography|url= https://www.iucr.org/publ/50yearsofxraydiffraction|location=Chester, England |publisher=[[International Union of Crystallography]] |isbn=978-1-4615-9961-6 |chapter= Some Personal Reminiscences.|chapter-url=http://www.iucr.org/__data/assets/pdf_file/0014/743/andrade.pdf}}</ref>-->
* [[Walther Kossel]] (1911)<ref name=PhysicsTree/>
* {{Nowrap|[[Rudolf Tomaschek]] (1921)}}<ref name=PhysicsTree/>
}}
}}

'''Philipp Eduard Anton von Lenard''' ({{IPA|de|ˈfɪlɪp ˈleːnaʁt|lang|De-Philipp Lenard.ogg}}; 7 June 1862 – 20 May 1947) was a Hungarian–German [[experimental physicist]] who received the [[Nobel Prize in Physics]] in 1905 for his work on [[cathode rays]].<ref name=Nobel1905>{{Cite web|title=The Nobel Prize in Physics 1905|url=https://www.nobelprize.org/prizes/physics/1905/summary/|url-status=live|publisher=[[Nobel Foundation]]| archive-url = https://web.archive.org/web/20081008110704/http://nobelprize.org/nobel_prizes/physics/laureates/1905/index.html|archive-date=2008-10-08|access-date =2008-10-09}}</ref> This work led to his experimental realization of the [[photoelectric effect]], discovering that the energy (speed) of the [[electron]]s ejected from a [[cathode]] depends only on the [[frequency]], and not the [[Intensity (physics)|intensity]] of light.

As an active proponent of the [[Nazism|Nazi ideology]], Lenard supported [[Adolf Hitler]] in the 1920s and was an important role model for the {{Lang|de|[[Deutsche Physik]]}} movement during the [[Nazi Germany|Nazi period]]. Notably, he labeled [[Albert Einstein]]'s contributions to theoretical physics as "[[Criticism of the theory of relativity#Chauvinism and antisemitism|Jewish physics]]."

== Biography ==
Philipp Eduard Anton von Lenard was born on 7 June 1862 in Pressburg (now [[Bratislava]], Slovakia), then located in the [[Kingdom of Hungary]], the son of Philipp von Lenard (1812–1896), a wine merchant in Pressburg, and Antonie Baumann (1831–1865).<ref>Neue deutsche biografie XIV, 1984 München</ref> His father's family had originally come from [[Tyrol]], while his mother's family originated from [[Baden]]; both parents were German-speaking.<ref>{{cite book | last = Pöss | first = Ondrej | editor-first = Myrtil | editor-last = Nagy | chapter = Karpatskí Nemci | title = Naše národnostné menšiny | publisher = Fórum inštitút pre výskum menšín | year = 2012 | location = Šamorín|pages = 9–12|isbn = 978-80-89249-57-2 }}</ref> Among his mostly Germanic ancestors, he also had Hungarian ones.

Lenard attended the ''Pozsonyi Királyi Katolikus Főgymnasium'' (today [[Gamča]]), and as he records in his autobiography, this made a big impression on him (especially the personality of his teacher, Virgil Klatt).<ref name="Lenard">{{cite web |first= Gabriel |last=Palló|title= Fizikai Szemle; ELEKTRON ÉS ÉTERFIZIKA: LÉNÁRD FÜLÖP (1862–1947)|url= http://www.kfki.hu/fszemle/archivum/fsz9704/pallo.html|publisher= [[Hungarian Academy of Sciences]], Physical Sciences Section|page= 116|language= hu|year=1997|quote= Written in Hungarian by the autobiography of the famous physicist: Philipp Lenard, Erinnerungen eines Naturwissenschaftlers, der Kaiserreich, Judenschaft und Hitler erlebt hat. Geschrieben September 1930 bis Mrz 1931}}</ref> In 1880, he studied physics and chemistry in [[Vienna]] and in [[Budapest]].<ref name="Lenard"/> In 1882, he left Budapest and returned to Pressburg, but in 1883 moved to [[Heidelberg]] after his tender for an assistant's position at the [[Eötvös Loránd University|University of Budapest]] was refused. At the [[University of Heidelberg]], he studied under [[Robert Bunsen]], interrupted by one semester in Berlin with [[Hermann von Helmholtz]]. He also studied under [[Georg Quincke]], and received his [[Ph.D.]] in 1886.<ref name=NobelBio>{{Cite web |title=Philipp Lenard – Biographical|url=https://www.nobelprize.org/prizes/physics/1905/lenard/biographical/|url-status=live|publisher=[[Nobel Foundation]]|archive-url=https://web.archive.org/web/20250430102412/https://www.nobelprize.org/prizes/physics/1905/lenard/biographical/|archive-date=2025-04-30|access-date=2024-09-15}}</ref><ref>{{cite web|url=http://www.mek.iif.hu/porta/szint/tarsad/tudtan/nobel/html/lenard/lenard.htm |title=Lénárd Fülöp |publisher=Mek.iif.hu |access-date=13 July 2013}}</ref> The following year, he worked as a demonstrator under [[Loránd Eötvös]] at Budapest.<ref name="Lenard"/>

In 1892, Lenard became a {{Lang|de|[[Privatdozent]]}} and an assistant to [[Heinrich Hertz]] at the [[University of Bonn]]; Lenard and Hertz conducted experiments with [[cathode rays]], which led to him winning the 1905 [[Nobel Prize in Physics]].<ref name=NobelBio/> After brief stays at the [[University of Breslau]] (1894–1895), [[RWTH Aachen]] (1895–1896), and the University of Heidelberg (1896–1898), he was appointed Professor Ordinarius at the [[University of Kiel]] in 1898. In 1907, he returned to Heidelberg, where he remained until his retirement in 1931.<ref>{{Cite web
|title=Philipp Lenard|url=https://history.aip.org/phn/11805003.html|url-status=live|publisher=[[American Institute of Physics]]|archive-url=https://web.archive.org/web/20250418081104/https://history.aip.org/phn/11805003.html|archive-date=2025-04-18|access-date=2025-11-14}}</ref>

Lenard died on 20 May 1947 in [[Messelhausen]] at the age of 84.<ref name=NobelBio/>

== Research ==
=== Cathode rays ===
[[File:The dynamid atomic model, by Philipp Lenard, 1903.gif|thumb|The dynamid atomic model, by Philipp Lenard, 1903]]

Lenard's major contribution to physics was in the study of [[cathode rays]], which he began in 1888. Prior to his work, cathode rays were produced in primitive, partially evacuated glass tubes that had metallic electrodes in them, across which a [[high voltage]] could be placed. Cathode rays were difficult to study using this arrangement, because they were inside sealed glass tubes, difficult to access, and because the rays were in the presence of air molecules. He overcame these problems by devising a method of making small metallic windows in the glass that were thick enough to be able to withstand the pressure differences, but thin enough to allow passage of the rays. Having made a window for the rays, he could pass them out into the laboratory, or, alternatively, into another chamber that was completely evacuated. These windows have come to be known as [[Crookes tube#Lenard window|Lenard windows]]. He was able to conveniently detect the rays and measure their intensity by means of paper sheets coated with phosphorescent and materials.<ref>{{cite journal | first=Philipp | last=Lenard | title=Ueber Kathodenstrahlen in Gasen von atmosphärischem Druck und im äussersten Vacuum | journal=Annalen der Physik | volume=287 | issue=2 | pages=225–267 | year=1894 | doi=10.1002/andp.18942870202|bibcode = 1894AnP...287..225L | url=https://zenodo.org/record/1423886 }}</ref> In particular, he came to use pentadecylparatolylketone, which was very effective as a cathode ray detector but, unfortunately for Lenard, not fluorescent in [[X-ray]]s. When [[Wilhelm Röntgen]] set out to reproduce Lenard's results, he was forced to use [[barium]] [[platinocyanide]] instead because Lenard had purchased all the available pentadecyl-para-tolyl ketone. The alternative was sensitive to both [[Ultraviolet radiation|UV]] and X-rays allowing Röntgen to discover X-rays.<ref>{{Cite web |last=Schwarcz  |first=Joe |title=The Right Chemistry: Discovery of X-ray changed medicine forever |url=https://montrealgazette.com/opinion/columnists/the-right-chemistry-discovery-of-a-new-kind-of-ray-changed-practice-of-medicine-forever |access-date=17 September 2024 |website=Montreal Gazette.}}</ref>

Lenard observed that the absorption of cathode rays was, to first order, proportional to the density of the material they were made to pass through. This appeared to contradict the idea that they were some sort of [[electromagnetic radiation]]. He also showed that the rays could pass through some inches of air of a normal density, and appeared to be scattered by it, implying that they must be particles that were even smaller than the molecules in air. He confirmed some of [[J. J. Thomson]]'s work, which eventually arrived at the understanding that cathode rays were streams of negatively charged energetic particles. He called them [[electron|quanta of electricity]] or for short [[quantum|quanta]], after [[Helmholtz]], while Thomson proposed the name "corpuscles", but eventually ''[[electron]]s'' became the everyday term.<ref>{{Cite web |title=Lenard's Nobel lecture (1906) |url=https://www.nobelprize.org/uploads/2018/06/lenard-lecture.pdf |access-date=7 July 2023}}</ref> In conjunction with his and other earlier experiments on the absorption of the rays in metals, the general realization that electrons were constituent parts of the atom enabled him to claim correctly that for the most part atoms consist of empty space. He proposed that every [[atom]] consists of empty space and electrically [[Neutral particle|neutral]] corpuscules called "dynamids", each consisting of an electron and an equal positive charge.

[[Image:Lenard window tube labeled.svg|thumb|Lenard window tube]]

As a result of his [[Crookes tube]] investigations, he showed that the rays produced by irradiating metals in a vacuum with ultraviolet light were similar in many respects to cathode rays. His most important observation was that the energy of the rays in the [[photoelectric effect]] was independent of the light intensity. His interpretation however imagined that the light released rays already moving inside of atoms and he made no connection between the energy of the light and the electron.<ref>{{cite journal |title=Philipp Lenard and the Photoelectric Effect, 1889-1911 |first=Bruce R. |last=Wheaton |journal=Historical Studies in the Physical Sciences |volume=9 |year=1978 |pages=299–322 |doi=10.2307/27757381 |jstor=27757381}}</ref>

These latter observations were [[Annus Mirabilis papers#Photoelectric effect|explained]] by [[Albert Einstein]] as a quantum effect. Each quantum of light with sufficient energy resulted in one photoelectron, so the light intensity affected the electron flux intensity but not its energy. This theory predicted that the plot of the cathode ray energy versus the frequency would be a straight line with a slope equal to the [[Planck constant]], ''h''. This was shown to be the case some years later. The photoelectric quantum theory was the work cited when Einstein was awarded the Nobel Prize in Physics in 1921. Suspicious of the general adulation of Einstein, he became a prominent [[Criticism of the theory of relativity|skeptic of relativity]] and of Einstein's theories generally; he did not, however, dispute Einstein's explanation of the photoelectric effect. Lenard grew extremely resentful of the credit accorded to Wilhelm Röntgen, who received the first [[Nobel Prize in Physics]] in 1901 for the discovery of X-rays.<ref>{{cite web|url=https://theconversation.com/when-science-gets-ugly-the-story-of-philipp-lenard-and-albert-einstein-43165|title=When science gets ugly – the story of Philipp Lenard and Albert Einstein |date=16 June 2015 |access-date=25 August 2018}}</ref><ref>{{cite web|url=https://www.space.com/36767-natgeo-genius-science-political.html|title=Science Gets Political, Einstein Gets Fired in Nat Geo's 'Genius'|website=[[Space.com]] |date=9 May 2017 }}</ref> Lenard wrote that he—not Röntgen—was the "mother of the X-rays," since he had invented the apparatus used to produce them; Lenard likened Röntgen's role to that of a "midwife" who merely assists with the birth.<ref>{{cite journal | journal = Cleveland Clinic Journal of Medicine | date = July 1953 | volume=20 | number=3 | pages=400–406 | last=Glaser | first=Otto | title=The Human Side of Science | doi = 10.3949/ccjm.20.3.400 | url=https://www.ccjm.org/content/ccjom/20/3/400.full.pdf | access-date=15 May 2025}}</ref>

=== Meteorological contributions ===
<!--'Spray electrification' and 'Waterfall effect' redirect here-->
Lenard was the first person to study what has been termed the ''Lenard effect'' in 1892. This is the separation of electric charges accompanying the [[aerodynamics|aerodynamic]] breakup of water drops. It is also known as '''spray electrification'''<!--boldface per WP:R#PLA--> or the '''waterfall effect'''<!--boldface per WP:R#PLA-->.<ref>{{cite web |url=https://glossary.ametsoc.org/wiki/Lenard_effect |title=Lenard effect - Glossary of Meteorology |publisher=American Meteorological Society |date=29 March 2024 |access-date=23 September 2025 |url-status=live |archive-url=https://web.archive.org/web/20120205021120/http://amsglossary.allenpress.com/glossary/search?id=lenard-effect1 |archive-date=5 February 2012 }}</ref><ref>{{Cite book |last=Byers |first=Horace Robert  |url=http://archive.org/details/thunderstormelec0000hora |title=Thunderstorm electricity |date=January 1, 1953 |publisher=University of Chicago Press}}</ref>{{rp|153}}

Lenard conducted studies on the size and shape distributions of raindrops and constructed a novel [[wind tunnel]] in which water droplets of various sizes could be held stationary for a few seconds. He was the first to recognize that large raindrops are not tear-shaped, but are rather shaped something like a hamburger bun.<ref>
{{cite web
 | url=https://hypertextbook.com/facts/2001/IgorVolynets.shtml
 | title=Diameter of a raindrop
 | first=Igor
 | last=Volynets
 | year=2001
 | website=The Physics Factbook
 | editor-last=Elert
 | editor-first=Glenn
 | access-date=19 August 2019
}}</ref>

== ''Deutsche Physik'' ==
Lenard is remembered today as a strong [[German nationalist]] who despised "English physics", which he considered to have stolen its ideas from Germany.<ref name="Rydell2017">{{cite book|first=Anders|last=Rydell|title=The Book Thieves: The Nazi Looting of Europe's Libraries and the Race to Return a Literary Inheritance|url=https://books.google.com/books?id=yMQiDAAAQBAJ&pg=PA86|date=7 February 2017|publisher=Penguin|isbn=978-0-7352-2124-6|pages=86–}}</ref><ref name="Kojevnikov2011">{{cite book|first=Alexei|last=Kojevnikov|title=Weimar Culture and Quantum Mechanics: Selected Papers by Paul Forman and Contemporary Perspectives on the Forman Thesis|url=https://books.google.com/books?id=1FEsrL8aQVoC&pg=PA33|year=2011|publisher=World Scientific|isbn=978-981-4293-12-9|pages=33–|bibcode=2011wcqm.book.....K|doi=10.1142/7581}}</ref><ref name="Steinhaus2016">{{cite book|first=Hugo|last=Steinhaus|title=Mathematician for All Seasons: Recollections and Notes, Vol. 2 (1945–1968)|url=https://books.google.com/books?id=IeOKCwAAQBAJ&pg=PA105|date=8 February 2016|publisher=Birkhäuser|isbn=978-3-319-23102-0|pages=105–}}</ref> 
Lenard and fellow experimental physicist [[Johannes Stark]] were increasingly sidelined and ignored in the 1920's due to their rejection of the theory of relativity and of quantum mechanics.<ref>{{Cite journal |last=Walker |first=Mark |date=1989-01-01 |title=National Socialism and German Physics |url=https://journals.sagepub.com/doi/10.1177/002200948902400103 |journal=Journal of Contemporary History |language=en |volume=24 |issue=1 |pages=63–89 |doi=10.1177/002200948902400103 |issn=0022-0094|url-access=subscription }}</ref>
During the [[Nazism|Nazi]] regime, he was the outspoken proponent of the idea that Germany should rely on "{{lang|de|[[Deutsche Physik]]}}" and ignore what he considered the fallacious and deliberately misleading ideas of "Jewish physics", by which he meant chiefly the theories of Albert Einstein, including "the Jewish fraud" of [[theory of relativity|relativity]] (see also [[criticism of the theory of relativity]]).<ref>[https://www.scientificamerican.com/article/how-2-pro-nazi-nobelists-attacked-einstein-s-jewish-science-excerpt1/ "How 2 Pro-Nazi Nobelists Attacked Einstein’s "Jewish Science"]. ''Scientific American''. Retrieved 30 January 2021.</ref> Lenard became Chief of Aryan Physics under the Nazis.<ref>[https://www.nobelprize.org/nobel_prizes/physics/laureates/1905/lenard-bio.html Nobel prize 1905]</ref>
In his foreword to his four volume science textbook {{lang|de|[[Deutsche Physik]]}} he argued that like everything that man creates, science is determined by race.<ref>{{Cite book |last=Gimbel |first=Steven |title=Einstein's Jewish Science: Physics at the Intersection of Politics and Religion |date=2013 |publisher=Johns Hoskins University Press |isbn=978-1421411828 |page=2}}</ref>

Lenard's book, ''Great Men in Science, A History of Scientific Progress'', first published in English in 1933,<ref>{{Cite book |last=Lenard |first=Philipp |url=https://catalog.loc.gov/vwebv/search?searchCode=LCCN&searchArg=33024226&searchType=1&permalink=y |title=Great men of science: a history of scientific progress |date=1933 |publisher=The Macmillan Company |location=New York |language=English |translator-last=Hatfield |translator-first=H. |quote=translated from the second German edition by Dr. H. Stafford Hatfield, with a preface by E. N. da C. Andrade |access-date=3 October 2023}}</ref> claimed these men were all "Aryan scientists".<ref>{{Cite book |last=Josephson |first=Paul R. |title=Totalitarian science and technology |date=2005 |publisher=Humanities Press |isbn=978-1-59102-321-0 |edition=2nd |series=Control of nature |location=Amherst, N.Y}}</ref> The individual scientists selected for inclusion by Lenard do not include Einstein or [[Marie Curie]], nor any other twentieth-century scientist. The publisher included what now appears to be a remarkable understatement on page xix of the 1954 English edition: "While Professor Lenard's studies of the men of science who preceded him showed not only profound knowledge but also admirable balance, when it came to men of his own time he was apt to let his own strong views on contemporary matters sway his judgment. In his lifetime he would not consent to certain modifications that were proposed in the last study of the series".

The ideologists of Nazism in Germany argued that the [[theory of relativity]] was inextricably linked to [[materialism]] and [[Marxism]].<ref name="t356">{{cite book | last=Frank | first=Philipp | title=Einstein, His Life and Times | publisher=Knopf Doubleday Publishing Group | year=2013 | orig-year=1947 | isbn=978-0-307-83136-1 | url=https://books.google.com/books?id=AQg5AAAAQBAJ&pg=RA1-PT342 | language=en | access-date=23 October 2024 | page=35 | quote=Objective real space devoid of material properties, motion divorced from matter, are metaphysical phantoms that sooner or later have to be expelled from the physical picture of the world.… The historic service rendered by Einstein was the criticism of the old metaphysical conceptions of space and time.… In Einstein’s theory space-time is an inseparable property of matter itself. Such is the basic idea of Einstein’s general theory of relativity. The idealistic conception of space-time as a category of thought is swept away.… Before us is the first outline, still far from perfect, of the dialectical materialistic understanding of space and time. Once again dialectical materialism has triumphed.}}</ref> The most notable of them was Lenard.<ref name="t356"/> Lenard had become the head of ''[[Deutsche Physik]]'' ("[[Aryan Race|Aryan]] physics"), a philosophy of science that dismissed the contributions of [[Albert Einstein]] and other [[Jewish]] physicists as "Jewish physics".<ref name="nobel">{{cite web | title=The Nobel Prize in Physics 1905 | website=NobelPrize.org | date=20 May 1947 | url=https://www.nobelprize.org/prizes/physics/1905/lenard/biographical/ | access-date=24 October 2024}}</ref>  Einstein had discovered the mechanism of the [[photoelectric effect]], which Lenard had detected experimentally but could not explain theoretically.<ref name="nobel"/>

Lenard called Einstein's theories "Jewish fraud."<ref name="z006">{{cite book | last1=Galison | first1=Peter L. | last2=Holton | first2=Gerald | last3=Schweber | first3=Silvan S. | title=Einstein for the 21st Century: His Legacy in Science, Art, and Modern Culture | publisher=Princeton University Press | date=27 February 2018 | isbn=978-0-691-17790-8 | url=https://books.google.com/books?id=rsY9DwAAQBAJ&dq=Einstein+%2522jewish+fraud%2522&pg=PA12 | access-date=10 May 2025 | page=12}}</ref> Lenard especially hated physics based on advanced mathematics.<ref name="i308">{{cite book | last=Bader | first=Rolf | title=How Music Works: A Physical Culture Theory | publisher=Springer Nature | date=7 April 2021 | isbn=978-3-030-67155-6 | url=https://books.google.com/books?id=QxIoEAAAQBAJ&dq=einstein+Lenard+complicated+math&pg=PA248 | access-date=10 May 2025 | page=248}}</ref> Lenard, in particular, and in general the experimental physicists of that time did not understand advanced mathematics.<ref name="e521">{{cite book | last1=Hillman | first1=Bruce J. | last2=Ertl-Wagner | first2=Birgit | last3=Wagner | first3=Bernd C. | title=The Man Who Stalked Einstein: How Nazi Scientist Philipp Lenard Changed the Course of History | publisher=Rowman & Littlefield | date=16 April 2015 | isbn=978-1-4930-1569-6 | url=https://books.google.com/books?id=AkV9CAAAQBAJ&dq=einstein+Lenard+advanced+math&pg=PR16 | access-date=10 May 2025 | page=xvi}}</ref> They described their laboratory observations in prose rather than mathematically.<ref name="e521"/>

== Awards ==
{| class="wikitable"
! Country
! Year
! Institute
! Award
! Citation
! {{Reference column heading}}
|-
| {{Flagdeco|United Kingdom}} [[United Kingdom of Great Britain and Ireland|United Kingdom]]
| 1896
| [[Royal Society]]
| [[Rumford Medal]]
| "For their investigations of the phenomena produced outside a highly exhausted tube, through which an electrical discharge is taking place" (with [[Wilhelm Röntgen]])
| <ref>{{Cite web|title=Rumford Medal|url=https://royalsociety.org/medals-and-prizes/rumford-medal/|publisher=[[Royal Society]]|access-date=2024-06-19}}</ref>
|-
| {{Flagdeco|Kingdom of Italy}} [[Kingdom of Italy|Italy]]
| 1896
| [[Accademia dei XL]]
| [[Matteucci Medal]]
|
| <ref>{{Cite web|title=Medals|url=https://www.accademiaxl.it/en/activities/medals/|publisher=[[Accademia dei XL]]|access-date=2025-11-04}}</ref>
|-
| {{Flag|Sweden|1844}}
| 1905
| [[Royal Swedish Academy of Sciences]]
| [[Nobel Prize in Physics]]
| "For his work on cathode rays"
| <ref name=Nobel1905/>
|-
| {{Flag|United States|1912}}
| 1932
| [[Franklin Institute]]
| [[Franklin Medal]]
| "For research of cathode rays and photoelectricity"
| <ref>{{Cite web|title=Philipp Lenard|url=https://fi.edu/en/awards/laureates/philipp-lenard|url-status=live|publisher=[[Franklin Institute]]|archive-url=https://web.archive.org/web/20250401053938/https://fi.edu/en/awards/laureates/philipp-lenard|archive-date=2025-04-01|access-date=2025-11-14}}</ref>
|}

== Legacy ==
{{Lang|de|[[Helmholtz-Gymnasium Heidelberg]]}} had been named the {{Lang|de|Philipp-Lenard-Schule}} from 1927 until 1945, when it was renamed by the Mayor of Heidelberg as part of the [[denazification]] process.<ref name="HGH1">Geierhaas, Theo. [http://www.helmholtz-heidelberg.de/gymnasium/unser-helmholtz/schulgeschichte/ "Schulgeschichte"]. Helmholtz-Gymnasium Heidelberg. Retrieved 4 March 2019 {{in lang|de}}.</ref> 

[[Lenard (crater)|Lenard crater]] near the [[Lunar north pole|north pole of the Moon]] was named in his honor from 2005 (approved in 2008) until 2020. When the [[International Astronomical Union]] learned of Lenard's Nazi connection, they decided to drop the name.<ref>{{cite web|url=https://www.prospectmagazine.co.uk/science-and-technology/astronomists-unknowingly-dedicated-moon-craters-to-nazis-will-the-next-historical-reckoning-be-at-cosmic-level|title=Astronomers unknowingly dedicated moon craters to Nazis|date=26 June 2020|first=Philipp|last=Ball|website=prospectmagazine.co.uk|access-date=26 June 2020}}</ref><ref>{{GPN|14503}}</ref>

== Cultural references ==
* Lenard's [[criticism of the theory of relativity]] and his crusade against Einstein and his theories was covered in an episode of ''[[Dark Matters: Twisted But True]]'', in a segment entitled "Einstein's Revenge".
* The life of Lenard and the interrelationship between his work and that of Albert Einstein is the subject of the book ''The Man Who Stalked Einstein: How Nazi Scientist Philipp Lenard Changed the Course of History'' by Bruce J. Hillman, Birgit Ertl-Wagner and Bernd C. Wagner.
* Lenard was portrayed by actor [[Michael McElhatton]] in the 2017 [[National Geographic (U.S. TV channel)|National Geographic]] anthology period drama television series ''[[Genius (2017 TV series)|Genius]]''.<ref>{{cite web|url=https://www.imdb.com/title/tt5985794/ |title=Genius – Chapter One |publisher=imdb.com |access-date=6 May 2017}}</ref>
* Lenard featured as the villain in the seventh episode of [[Super Science Friends]].

== Bibliography ==
* {{cite book | last=Lenard | first=Philipp | title=Über Kathodenstrahlen (On Cathode Rays) | language=de | year=1906 }}
* {{cite book | last=Lenard | first=Philipp | title=Über Aether und Materie (On Aether and Matter) | language=de }}
* {{cite book | last=Lenard | first=Philipp | title=Probleme komplexer Moleküle (Problems of complex molecules) | language=de | year=1914 }}
* {{cite book | last=Lenard | first=Philipp | title=Quantitatives über Kathodenstrahlen | language=de | year=1918 }}
* {{cite book | last=Lenard | first=Philipp | title=Über das Relativitätsprinzip (On the Principle of Relativity)| language=de | year=1918 }}
* {{cite book | last=Lenard | first=Philipp | title=Aether und Uraether | language=de | year=1921 }}
* {{cite book | last=Lenard | first=Philipp | title=Grosse Naturforscher | url=https://archive.org/details/b29824126 | language=de | year=1930 }}
* Lenard, Philipp (1931) (in German). ''Erinnerungen eines Naturforschers''. New edition: ''Erinnerungen eines Naturforschers – Kritische annotierte Ausgabe des Originaltyposkriptes von 1931/1843'' (Arne Schirrmacher, ed.). Springer Verlag, Heidelberg 2010, 344 pages, {{ISBN|978-3-540-89047-8}}, e-{{ISBN|978-3-540-89048-5}}.
* {{cite book | last=Lenard | first=Philipp | title=Great Men of Science | url=https://archive.org/details/in.ernet.dli.2015.203547 | location=London | publisher=G. Bell and sons | year=1933 | oclc=1156317}}
* {{cite book | last=Lenard | first=Philipp | title=Deutsche Physik in vier Bänden | language=de | publisher=J.F. Lehmann | year=1936 | oclc=13814543}} 1. ''Einleitung und Mechanik'', 2. ''Akustik und Wärmelehre'', 3. ''Optik, Elektrostatik und Anfänge der Elektrodynamik'' (or: 3. ''Optik und Elektrizitätslehre 1. Teil''), 4. ''Magnetismus, Elektrodynamik und Anfänge von weiterem'' (or: ''Elektrizitätslehre 2. Teil''). Later editions, 1943

== See also ==
* [[Cavity magnetron]]
* [[Fluid thread breakup]]

== Notes ==
{{reflist}}

== References ==
* {{cite book |last=Beyerchen |first=Alan |title=Scientists under Hitler: Politics and the physics community in the Third Reich |location=New Haven, CT |publisher=Yale University Press |year=1977 |isbn=978-0300018301 |url=https://archive.org/details/scientistsunderh00alan }}
* {{cite book |last=Cornwell |first=John |title=Hitler's Scientists: Science, War and the Devil's Pact |publisher=Penguin Books |year=2003 |isbn=978-0142004807 |url=https://archive.org/details/isbn_9780142004807 }}
* {{cite book |editor-last=Hentschel |editor-first=Klaus |title=Physics and National Socialism: An anthology of primary sources |location=Basel |publisher=Birkhaeuser |year=1996 |isbn=978-3764353124 }}
* {{cite book |last=Walker |first=Mark |title=Nazi science: Myth, truth, and the German atomic bomb |location=New York |publisher=Harper Collins |year=1995 |isbn=978-0306449413 }}
* {{cite journal |last=Wolff |first=Stephan L. |title=Physicists in the 'Krieg der Geister': Wilhelm Wien's 'Proclamation' |journal=[[Historical Studies in the Natural Sciences|Historical Studies in the Physical and Biological Sciences]] |volume=33 |issue=2 |year=2003 |pages=337–368 |doi=10.1525/hsps.2003.33.2.337 }}

== External links ==
{{commons category}}
* {{Nobelprize}} including the Nobel Lecture, 28 May 1906 ''On Cathode Rays''
* [http://nobelprize.org/physics/laureates/1905/lenard-lecture.html On Cathode Rays]
* [http://www.crtsite.com/page7.html The Cathode Ray Tube site]
* {{MathGenealogy|id=73821}}
* {{PM20}}

{{Nobel Prize in Physics Laureates 1901-1925}}
{{1905 Nobel Prize winners}}
{{Hungarian Nobel Laureates}}
{{Authority control}}

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