Mole Day

Happy Mole Day!

Wait, not that kind of mole!

I’m talking about a mole from chemistry. A mole (or mol) is a standard, scientific unit for measuring large quantities of very small entities, such as atoms.

Why October 23^rd? It’s from Avogadro’s number.

Avogadro’s number refers to the number of units in one mole of any substance. For example, it is the number of atoms found in 12 grams of carbon-12.

Avogadro’s Number = 6.022 x 10²³

National Mole Day Foundation

This number was named after Amedeo Avogadro in honor of his contributions to chemistry. For the chemistry professors, I’ll note that Avogadro’s number is dimensionless, while the closely related Avogadro’s constant is 6.022 x 10²³ mol⁻¹. (See the mol unit at the end)

Today’s date refers to the “ten to the power of twenty-three” at the end of the number, when it’s written in scientific notation.

The number of digits in the 6.022 part has varied with scientific knowledge. Since Avogadro’s number is often written as the short 6.02 x 10²³, Mole Day celebrations can peak at 6:02 a.m. or p.m. on October 23^rd.

Here’s my favorite drawing from the National Mole Day Foundation: