National Mole Day
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Overview
National Mole Day is an unofficial holiday celebrated by chemists, chemistry students, and enthusiasts on October 23rd, from 6:02 a.m. to 6:02 p.m. It commemorates Avogadro's number (approximately 6.022 x 10^23), which defines the number of particles (atoms, molecules, ions, etc.) in one mole of a substance. The day aims to foster interest in chemistry and celebrate this fundamental unit of measurement in a fun and engaging way.
Origin and story
Mole Day's date (10/23) and time (6:02 a.m. to 6:02 p.m.) are directly derived from the digits of Avogadro's number, 6.02 x 10^23.
The term 'mole' was first coined by German chemist Wilhelm Ostwald in 1900, derived from the Latin word 'moles' meaning a 'heap' or 'pile.'
Quick facts
- DateOctober 23
- TypeCultural / community observance
- Great forFriends, Families, Classrooms, Teams
Also on this date
Ways to celebrate
This "mole" has nothing to do with the animal or the sauce — it's a chemistry teacher's tribute to one of science's most useful numbers.
Know what's actually being celebrated
The date and time, October 23 from 6:02 a.m. to 6:02 p.m., are a direct reference to Avogadro's number, approximately 6.02 x 10²³, which defines how many particles are in one mole of a substance — the basic counting unit chemists use for atoms and molecules.
Meet the teacher who built it into a holiday
Inspired by a 1980s magazine article by educator Margaret Christoph, Wisconsin high school chemistry teacher Maurice Oehlke founded the National Mole Day Foundation on May 15, 1991, specifically to get students excited about chemistry.
Read the official source
Helpful resources:
Did you know?
The observance has spread well beyond Wisconsin — schools in the United States, Canada, Australia, and South Africa now mark the day with chemistry-themed activities and events.
Fun facts
- Mole Day's date (10/23) and time (6:02 a.m. to 6:02 p.m.) are directly derived from the digits of Avogadro's number, 6.02 x 10^23.
- The term 'mole' was first coined by German chemist Wilhelm Ostwald in 1900, derived from the Latin word 'moles' meaning a 'heap' or 'pile.'
- If you had a mole of standard 8.5x11 sheets of paper, the stack would reach from the Earth to the Sun and back over a million times.
Sources and attribution
What Is Mole Day? (National Mole Day Foundation)
External links may lead to third-party websites.
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FAQ
- When is National Mole Day?
- It is observed on October 23 each year.
- What is National Mole Day?
- National Mole Day is an unofficial holiday celebrated by chemists, chemistry students, and enthusiasts on October 23rd, from 6:02 a.m. to 6:02 p.m. It commemorates Avogadro's number (approximately 6.022 x 10^23), which defines the number of particles (atoms, molecules, ions, etc.) in one mole of a substance. The day aims to foster interest in chemistry and celebrate this fundamental unit of measurement in a fun and engaging way.
- How do people celebrate National Mole Day?
- Do something chemistry-themed at 6:02 — the date and time reference Avogadro's number, and Wisconsin teacher Maurice Oehlke founded the National Mole Day Foundation in 1991 to spark student interest in the subject.
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