October 2020

Happy Mole Day! Join us in celebrating with a new podcast episode

Mole Day takes place each year on the 23 October and is observed by a niche group of people, as it celebrates the mole, the unit for measuring atoms, molecules, or other specific particles.

The day begins at 6:02am, which in American date notation reads 6:02, 10/23, which chemists will recognise as being similar to Avogadro’s Constant (which the mole is based upon): 6.02 x 10^23. 

Lorenzo Romano Amedeo Carlo Avogadro

In 1812, Amadeo Avogadro proposed that the number of molecules in equal volumes of gas (at the same temperature and pressure) are equal.  And nearly 100 years later, Jean Baptiste Perrin determined the number of molecules in one gram-molecule of oxygen, and it was (you guessed it) 6.02 x 10^23 (give or take a few billion). He named this number after Avogadro.

Fast forward to 80 years after that, and the National Mole Day Foundation was created in 1991 by a chemistry teacher in Wisconsin.

Now each year, chemistry teachers around the United States use Mole Day to teach the principles of metrology (measurement) to their students with a day of mole-related activities. But the day is catching on elsewhere, and now chemists all over are embracing it.

To celebrate this Mole Day, we spoke with Sarah Hill, Science Leader in the Inorganic Analysis team within the UK’s National Measurement Laboratory (NML) about the mole and the role of measurement in chemistry and everyday life.

To learn more about measurement, visit the NML’s website, and follow us on Twitter for Mole Day facts.