The year1923 inscience andtechnology involved some significant events, listed below.

• January 17 (or 9) – First stable flight of the firstrotorcraft,Juan de la Cierva'sCierva C.4autogyro, in Spain.

• June –Hermann Oberth publishesDie Rakete zu den Planetenräumen ("By Rocket into Planetary Space").
• October 21 – First official public showing of aplanetarium projector, aZeiss model at theDeutsches Museum inMunich.^[1]

• March 23 – Thegovernor of Oklahoma signs House Bill 197 with the Montgomery amendment outlawing thetheory of evolution in public school textbooks purchased by the state, the first anti-Darwinian legislation passed in the United States.^[2]
• Karl von Frisch publishes "Über die 'Sprache' der Bienen. Eine tierpsychologische Untersuchung" ("On the 'language' of bees: an examination of animal psychology").^[3]

• Dirk Coster andGeorge de Hevesy publish their discovery of thetransition metalelementhafnium (₇₂Hf) inzirconium ore, working inCopenhagen (Latin:Hafnia).^[4][5]
• Niels Bohr and Dirk Coster, working in Copenhagen, produce a paper onX-ray spectroscopy and theperiodic system of the elements.^[6]
• Gilbert N. Lewis andMerle Randall's textbookThermodynamics and the Free Energy of Chemical Reactions is influential in the replacement of the concept ofchemical affinity byfree energy.^[7]

• Enigma machine first produced commercially.^[8]

• Otto Julius Zobel ofBell Labs describes the type ofsignal processingfilter sections based on theimage impedance design principle which will become known asZobel networks.^[9]
• December 29 –Vladimir K. Zworykin files his firstpatent (in theUnited States) for "television systems".

• Tanager Expedition.

• February – TheMaudsley Hospital, established jointly by theLondon County Council andHenry Maudsley, admits its first psychiatric patients.
• Capgras delusion, adelusional misidentification syndrome, is first described byJoseph Capgras.^[10]
• Firstdiphtheria vaccine byGaston Ramon,Emil von Behring andKitasato Shibasaburō.

• July 13 – AnAmerican Museum of Natural History expedition toMongolia underRoy Chapman Andrews is the first in the world to discoverfossildinosaureggs. Initially thought to belong to theceratopsianProtoceratops, they are determined in 1995 actually to belong to thetheropodOviraptor.^[11] On August 11 Peter Kaisen recovers the firstVelociraptor fossil known.^[12]

• Arthur Eddington publishes the textbookThe Mathematical Theory of Relativity inCambridge.

• Herbert Grove Dorsey invents the first practicalfathometer.

• Nobel Prizes
  • Physics:Robert Andrews Millikan
  • Chemistry:Fritz Pregl
  • Medicine:Frederick Banting andJohn Macleod
• Copley Medal:Horace Lamb
• Wollaston Medal for Geology:William Whitaker

• January 1 –Daniel Gorenstein (died1992),Americanmathematician.
• January 11 –Robert J. Gorlin (died2006), Americanpathologist.
• February 13 –Chuck Yeager (died2020), American pilot.
• February 14 –Doris Calloway, née Howes (died2001), Americannutritionist.
• February 20 –Helen Murray Free (died2021), American medical chemist.
• March 4 –Patrick Moore (died2012), Englishastronomer.
• March 9 –Walter Kohn (died2016), Viennese-bornphysicist.
• March 10 –Val Logsdon Fitch (died2015), American nuclear physicist, recipient of theNobel Prize in Physics.
• April 1 –Brigitte Askonas (died2013), Viennese-born Britishimmunologist.
• April 2 –G. Spencer-Brown (died2016), English mathematician.
• April 16 –Stewart Adams (died2019), English pharmaceutical chemist.
• April 21 –Albert (Ab) C. Perdeck (died2009),Dutchornithologist.
• April 23 –Walter Pitts (died1969), Americanlogician andcognitive psychologist.
• July 5 –Ivo Pitanguy (died2016),Brazilianplastic surgeon.
• July 12 –René Favaloro (died2000),Argentinecardiac surgeon.
• July 23 –Ulf Grenander (died2016),Swedish-bornmathematician.
• July 28 –Xia Peisu (died2014), Chinese computer scientist.
• July 31 –Stephanie Kwolek (died2014), Americanpolymer chemist.
• August 19 –Edgar F. Codd (died2003), English-born computer scientist.
• September 9 –Daniel Carleton Gajdusek (died2008), American virologist.
• September 13 –Miroslav Holub (died1998), Czech immunologist and poet.
• September 26 –John Ertle Oliver (died2011), American geophysicist.
• October 29 –Carl Djerassi (died2015), Viennese-born chemist.
• November 8 –Jack Kilby (died2005), American electrical engineer, recipient of the Nobel Prize in Physics.
• November 18 –Alan Shepard (died 1998), Americanastronaut.
• December 13 –Philip Warren Anderson (died2020), American physicist, recipient of the Nobel Prize in Physics.
• December 15 –Freeman Dyson (died2020), English-born theoretical physicist.

• February 10 –Wilhelm Röntgen (born1845), Germanphysicist, discoverer ofX-rays,Nobel laureate.
• February 24 –Edward Morley (born1838), Americanchemist.
• March 8 –Johannes Diderik van der Waals (born1837), Dutch physicist.
• March 27 –James Dewar (born1842), Scottish-born chemist.
• April 11 –Mary Treat (born1830), American naturalist.
• July 16 –Sydney Mary Thompson (born1847), Irish-borngeologist andbotanist.
• August 23 –Hertha Ayrton (born1854), Englishelectrical engineer.^[13]
• October 3 –Kadambini Ganguly (born1861), Indianphysician.
• December 2 –Henry Haversham Godwin-Austen (born1834), Englishsurveyor,geologist andnaturalist.
• December 7 –Sir Frederick Treves (born1853), English-bornsurgeon.
• December 27 –Gustave Eiffel (born1832), Frenchstructural engineer.

• 1923 in science
• 20th century in science
• 1920s in science

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