National Mole Day


National Mole Day exists to get people—particularly children—interested in chemistry. It takes place on October 23 each year, between 6:02 a.m. and 6:02 p.m., to commemorate Avogadro's number, which is roughly equivalent to (6.022 x 1023). The number is named after Italian scientist Amedeo Avogadro. A mole is a unit of measurement for measuring mass in chemistry, and one mole of a substance is equal to Avogadro's number of molecules or atoms of the substance. In the early 1980's, an article appeared in The Science Teacher about a teacher who celebrated the day. In May of 1991, the National Mole Day Foundation was created by Maurice Oehler, a now retired high school chemistry teacher from Wisconsin. The foundation organizes the day, and is made up primarily of high school teachers, but also includes elementary and middle school teachers, college professors, chemists and retired chemists, and people interested in chemistry. Schools across the country and world celebrate the day, and each year there is a different theme.

National Mole Day is observed next on Wednesday, October 23rd, 2019. It has always been observed annually on October 23rd.

How to Observe

Celebrate the day by learning some basic chemistry, or learning more about moles and Avogadro. If you have children, check to see if they are learning anything about moles in science class today. You could also visit the National Mole Day store, and the Facebook page for the day.

Occurrence Patterns

ObservedFirst YearLast Year
annually on October 23rd--



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