Mole Day Date in the current year: October 23, 2024

The idea of celebrating Mole Day was first mentioned in the early 1980s in an article in The Science Teacher. In 1991, Maurice Oehler founded the National Mole Day Foundation to promote the holiday and get people interested in chemistry.

Mole Day is celebrated on October 23, between 6:02 AM and 6:02 PM. The time and date are a reference to the Avodagro constant, also known as Avogadro's number, that defines the number of particles in one mole of substance. The constant is approximately equal to 6.02×10²³, which gives us the date 6:02 10/23 in the American date format.

Mole Day is celebrated by many high schools in North America, Australia, and South Africa. Some schools even organize Mole Week around the date of the holiday. Besides, Mole Day typically falls during National Chemistry Week held annually by the American Chemical Society.

Every year, the National Mole Day Foundation chooses a new theme for the celebration, which can be reflected in the events and activities held on the occasion. For example, the 1991 theme was “The Mole the Merrier”.