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.

Overview

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]}