Mole Day

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Mole Day is an unofficial holiday celebrated among chemists, chemistry students and chemistry enthusiasts on October 23, between 6:02 a.m. and 6:02 p.m.,[1][2][3][4] making the date 6:02 10/23 in the American style of writing dates. The time and date are derived from the Avogadro constant, which is approximately 6.02×1023, defining the number of particles (atoms or molecules) in one mole (mol) of substance, one of the seven base SI units.


Mole Day originated from a celebration by educator Margaret Christoph.[5] She wrote an article about her experiences in The Science Teacher in the 1980s[6] Inspired by this article, Maurice Oehler, a high school chemistry teacher from Prairie du Chien, Wisconsin, founded the National Mole Day Foundation (NMDF) on May 15, 1991.[6]

Many high schools around the United States, South Africa, Australia, and Canada celebrate Mole Day as a way to get their students interested in chemistry, with various activities often related to chemistry or moles.[6]

The American Chemical Society sponsors National Chemistry Week,[1] which occurs from the Sunday through Saturday during which October 23 falls. This makes Mole Day an integral part of National Chemistry Week.[citation needed]

See also[edit]


  1. ^ a b "National Chemistry Week Celebrates 20 Years", Chemical & Engineering News, vol. 85, no. 51, December 17, 2007, retrieved February 14, 2010
  2. ^ This Week in Chemical History, American Chemical Society, archived from the original on July 24, 2011, retrieved February 14, 2010
  3. ^ "Chemistry In The Spotlight", Chemical & Engineering News, vol. 88, no. 50, December 13, 2010, retrieved February 14, 2010
  4. ^ "Chemical club wins national recognition". Central Michigan Life. September 27, 2004. Retrieved October 8, 2012.[permanent dead link]
  5. ^ Christoph, Margaret (October 1985). "Mole day". The Science Teacher. 52 (7): 47–48. JSTOR 24145769. Retrieved October 24, 2022.
  6. ^ a b c "History of National Mole Day Foundation, Inc". Archived from the original on October 23, 2010.

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