National Mole Day

National Mole Day - Thursday, October 23, 2025

Special Interest Careers Science

October 23 between 6.02 am and 6:02pm is National Mole Day. It’s a basic chemistry algorithm, and not about those funny looking creatures called moles. It commemorates chemistry’s measuring unit called “Avogadro’s Number”. The day is celebrated as a means to bring awareness and create interest in the study of Chemistry. The day is celebrated by schools around the USA by doing mole and chemistry themed activities. In scientific terms, a mole is in relation to the molar mass of a given molecule. A mole is literally a unit of measurement to reflect an amount of a chemical substance.

History of National Mole Day

National Mole Day commemorates the hypothesis of an Italian scientist named Amadeo Avogadro. Born in 1776, he was one of the noted founders of physical chemistry and was only really given his dues fifty years after his hypothesis was created and after his death. He is known for his hypothesis called ‘‘Avogadro’s Law’’ in which pressure and a fixed temperature, equals volumes of gases which hold the same number of molecules.

A high school science teacher appeared in “The Science Teacher” in the 1980’s explaining her reasoning for wanting a National Mole Day. Maurice Oehler, a high school chemistry teacher read this and was inspired. He created National Mole Day. After this, on May 15, 1991, an organization called the National Mole Day Foundation (NMDF) was created. The foundation’s opening was announced through news releases to alert the media.

The idea was to gain members who were signed up to the foundation. These were usually students or simply those with an interest in chemistry, teachers and chemists most likely. Then ideas would be collected from high school chemistry teachers, especially those who were members of the foundation and who celebrated National Mole Day, and those ideas would be assembled into a newsletter which would be distributed to members of the foundation. By 1992, the foundation was no longer a foundation but rather a non-profit corporation in Wisconsin with a 9 person board of directors.

The day also falls during National Chemistry Week and does a great job of fostering interest in Chemistry amongst students. The day also has a theme every year starting in 1991 with ‘‘The Mole the Merrier’’, 2001’s ‘‘Molar Odyssey’’ and 2012’s ‘‘Animole Kingdom.’’ The day has also been called ‘‘Molemorial Day.’’

National Mole Day timeline

2017

MolEvengers

This year’s theme was ‘molEvengers’, an ode to The Avengers superhero franchise.

1991

The Mole Nine Yards

Inspired by the 1985 article by Christoph, Chemistry teacher Maurice Oehler created National Mole Day.

1985

Mole Hearted

Delaware Science teacher Margaret Christoph, writes about how every October, she celebrates the invented holiday with her students through activities.

1811

Mole Life Insurance

Avogadro hypothesizes that an equal volume of hydrogen and nitrogen at the same temperature and pressure, have the same number of molecules.

National Mole Day FAQs

Why is Mole Day celebrated?

Mole Day is celebrated every year on October 23 in order to commemorate Avogrado’s number (6.02 x 1023), a basic measurement unit used in chemistry.

Who established the National Mole Day Foundation?

The National Mole Day Foundation was established by retired high school teacher Maurice Oehler on May 15, 1991.

What is this year’s Mole Day theme?

This year’s punny National Mole Day theme is — wait for it — DispicaMole Me.

5 Facts About Moles

  1. GuacaMole

    A group of moles is also called a labor.

  2. Mole Model

    Avogadro’s number was set at 6.022*1023.

  3. Holey Moley

    A mole of smart phones is 6.02 x 1023 smart phones.

  4. The Mole the Merrier

    A mole of moles, contains enough calories to feed the entire population of Earth.

  5. Paracetamole

    The United States national debt could be repaid 86 million times with one mole of cents.

National Mole Day Activities

  1. Learn about molecular science

    Avogadro’s number is complicated enough and may leave you  scratching your head. Dive into his hypothesis by reading up on it, and on his life. Learn about his carelessness in the lab, his lack of back up for his experiment results and why he was not more celebrated enough while he lived due to his eccentric and introverted ways.

  2. Create a mole story

    Calling all students, creativity is key on this holiday. Try writing a short play displaying your interpretation of National Mole Day. Write stories, compose poems or songs, and make sure you add in the mole jokes. There is a lot of mole humor online, don’t be shy. How many puns can you come up with while doing this experiment?

  3. Bake a mole

    Measure, estimate and problem solve. Make edible mole goodies like cookies, cakes, cupcakes or brownies. If you’re really clever, use mole measurements like 1 mole of sugar etc. Remember, moles can be converted into grams.

Why We Love National Mole Day

  1. We’re getting creative

    This day allows us to flex our creativity by making mole themed art, making up a song about the mole or even making a creative video good enough to upload to social media, where we can tag our projects on @nationalmoleday’s social media.

  2. We’re testing the hypothesis

    This day means testing Avogadro’s number through determining how much water is in one mole of water? How much aluminium foil do you need to make a 0.5 mole sculpture? Don’t stress yourself out too much. Check online to get the answers.

  3. It’s silly fun

    Some hardcore National Mole Day fans celebrate by having breakfast at 6:02am and others bake large cakes, big enough to fit the periodic table. This day is educational as well as also silly which we love.

Also on Thu Oct 23, 2025...

Cereal Day
Oct 23
iPod Day
Oct 23
Mole Day
Oct 23