What it is

Mole Day is an annual celebration of the discovery by Amedeo Avogardo, an Italian chemist who lived from 1776 to 1858, of the unit called the mole. One mole is equal to the atomic mass, in grams, of a molecule. For instance, the atomic mass of Helium is 4, so one mole of Helium is 4 grams. A mole is expressed in scientific notation as 6.02 x 10²³. Therefore, Mole Day is celebrated from 6:02 AM to 6:02 PM on 10/23.

Origins of the mole

Avogardo first proposed his hypothesis in 1811. He based it on theories of Joseph Gay-Lussac, who discovered that all gases expand by the same amount. Avogardo's hypothesis was not appreciated, though, until two years after his death.

The beginning of Mole Day

Mole Day started in the early 1980s. On May 15, 1991, the National Mole Day Foundation was founded by Maurice Oehler, a teacher in Wisconsin. The purpose of this foundation is to spread interest about Mole Day and chemistry in general. Each year, Mole Day has a theme; in 1999, it was "it's a mole world." Students from across the U.S. celebrate Mole Day, creating projects that are often more about the animal than the unit.