Portal:History of science/Selected anniversaries/August 20
- 1710 - Birth of Thomas Simpson, British mathematician (d. 1761)
- 1779 - Birth of Jöns Jakob Berzelius, Swedish chemist (d. 1848)
- 1858 - Charles Darwin first publishes his theory of evolution in The Journal of the Proceedings of the Linnean Society of London, alongside Alfred Russel Wallace's same theory
- 1913 - Birth of Roger Wolcott Sperry, American neurobiologist, recipient of the Nobel Prize in Physiology or Medicine (d. 1994)
- 1915 - Death of Paul Ehrlich, German scientist, Nobel laureate (b. 1854)
- 1917 - Death of Adolf von Baeyer, German chemist, Nobel laureate (b. 1835)
- 1936 - Birth of Hideki Shirakawa, Japanese chemist, Nobel Prize laureate
- 1961 - Death of Percy Williams Bridgman, American physicist, Nobel laureate (b. 1882)
- 1963 - Death of Joan Voûte, Dutch astronomer (b. 1879)
- 1997 - Death of Norris Bradbury, American physicist (b. 1909)