Portal:History of science/Selected anniversaries/April 9
- 1770 - Birth of Thomas Johann Seebeck, German physicist (d. 1831)
- 1889 - Death of Michel Eugène Chevreul, French chemist (b. 1786)
- 1928 - Birth of Tom Lehrer, American musician and mathematician
- 1930 - Birth of F. Albert Cotton, American chemist (d. 2007)
- 1932 - Birth of Jim Fowler, American zoologist
- 1951 - Death of Vilhelm Bjerknes, Norwegian physicist (b. 1862)
- 1953 - Warner Brothers premieres the first 3-D film, entitled House of Wax
- 1957 - The Suez Canal in Egypt is cleared and opens to shipping
- 2002 - Death of Leopold Vietoris, Austrian mathematician (b. 1891)