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.[10]
December 14 – Max Planck restates his law, utilising the Planck postulate, at a meeting of the German Physical Society.[13][14]
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.
^De Vries, H. (1900). "Sur la loi de disjonction des hybrides" [On the law of hybrid disjunction]. Comptes rendus de l'Académie des sciences (in French). 130. Paris: 845–847.
^Tarry, Gaston (1900). "Le Probléme de 36 Officiers". Compte Rendu de l'Association Française pour l'Avancement des Sciences. 1. Secrétariat de l'Association: 122–123.
^Tarry, Gaston (1901). "Le Probléme de 36 Officiers". Compte Rendu de l'Association Française pour l'Avancement des Sciences. 2. Secrétariat de l'Association: 170–203.
^Treacher Collins, E. (1900). "Cases with symmetrical congenital notches in the outer part of each lid and defective development of the malar bones". Transactions of the Ophthalmological Societies of the United Kingdom. 20: 190–192.
^Mehra, Jagdish; Rechenberg, Helmut (2000). The Historical Development of Quantum Theory: The Quantum Theory of Planck, Einstein, Bohr, and Sommerfeld: Its Foundation and the Rise of Its Difficulties 1900–1925. Springer. pp. 50–53.
^Landsteiner, K. (1900). "Zur Kenntnis der antifermentativen, lytischen und agglutinierenden Wirkungen des Blutserums und der Lymphe". Zentralblatt für Bakteriologie. 27: 357–62.
^Yamashima, T. (2003). "Jokichi Takamine (1854–1922), the samurai chemist, and his work on adrenalin". Journal of Medical Biography. 11 (2): 95–102. doi:10.1177/096777200301100211. PMID12717538.
^Bennett, M. (1999). "One hundred years of adrenaline: the discovery of autoreceptors". Clinical Autonomic Research. 9 (3): 145–59. doi:10.1007/BF02281628. PMID10454061.