Editing 1900 in science (section)

==Physics==
* April 26 – [[Guglielmo Marconi]] patents the [[LC circuit|tuned circuit]].
* 6-10 August The first [[International Congress of Physics]] is held in Paris<ref name=":0">{{Cite book |last=Poskett |first=James |url=https://www.google.fr/books/edition/Horizons/6m8XEAAAQBAJ?hl=en&gbpv=1&dq=%22International+Congress+of+Physics%22+lebedev&pg=PT160&printsec=frontcover |title=Horizons: A Global History of Science |date=2022-03-24 |publisher=Penguin Books Limited |isbn=978-0-241-39411-3 |language=en}}</ref>
** [[Pyotr Lebedev]] presents first experimental evidence of [[radiation pressure]] during the conference<ref name=":0" />
* October 7 – [[Max Planck]] hosts fellow physicist [[Heinrich Rubens]] for tea and considers news that Rubens' experiments have contradicted Planck's theories. Later this evening, Planck reviews and refines his calculations to what will be announced on October 19 as [[Planck's law]].<ref>{{cite book|first=Edward G.|last=Steward|title=Quantum Mechanics: Its Early Development and the Road to Entanglement|publisher=Imperial College Press|location=London|year=2008|pages=36–42}}</ref>
* October 19 – [[Max Planck]] first states [[Planck's law]] of [[black-body radiation]] to a meeting of the [[German Physical Society]] in Berlin, marking the birth of modern [[quantum mechanics]].<ref>{{cite journal|last1=Planck|first1=M.|year=1900|title=Über eine Verbesserung der Wien'schen Spectralgleichung|url=https://archive.org/stream/verhandlungende01goog#page/n212/mode/2up|journal=[[Verhandlungen der Deutschen Physikalischen Gesellschaft]]|volume=2|pages=202–204}} Translated in {{cite book|last1=ter Haar|first1=D.|author-link=Dirk ter Haar|year=1967|chapter=On an Improvement of Wien's Equation for the Spectrum|url=http://www.ffn.ub.es/luisnavarro/nuevo_maletin/Planck%20%281900%29,%20Improvement%20of%20Wien%27s.pdf|title=The Old Quantum Theory|publisher=Pergamon Press|pages=79–81|lccn=66029628}}</ref>
* December 14 – Max Planck restates his law, utilising the [[Planck postulate]], at a meeting of the German Physical Society.<ref>{{cite journal|last1=Planck|first1=M.|year=1900|url=https://archive.org/stream/verhandlungende01goog#page/n247/mode/2up|title=Zur Theorie des Gesetzes der Energieverteilung im Normalspectrum|journal=Verhandlungen der Deutschen Physikalischen Gesellschaft|volume=2|pages=237–245}} Translated in {{cite book|last1=ter Haar|first1=D.|year=1967|url=http://www.ffn.ub.es/luisnavarro/nuevo_maletin/Planck%20%281900%29,%20Distribution%20Law.pdf|title=The Old Quantum Theory|publisher=Pergamon Press|page=82|lccn=66029628}}</ref>
* December 23 – [[Reginald Fessenden]], experimenting with a high-frequency spark transmitter, successfully transmits speech over a distance of about 1.6 kilometers (one mile), from [[Cobb Island, Maryland]], which appears to have been the first audio radio transmission.
* [[Gamma ray]]s discovered by [[Paul Ulrich Villard|Paul Villard]] while studying [[uranium]] decay.