Every year on 23 October, between 6:02 am and 6:02 pm, the chemistry world celebrates Mole Day. The date is a nod to Avogadro’s number (6.02 × 10²³), a constant that underpins so much of chemistry. However Mole Day is more than a quirky date in the calendar. It is a chance to explore one of the most challenging concepts for students, to make the abstract tangible, and to bring creativity into the classroom.
Why celebrate Mole Day?
As Sarah Sephton explained in her STEM Community blog, many students see mole calculations as a source of worry. A dedicated celebration provides an opportunity to slow down, unpick the concept, and even have some fun with it.
The mole is central to so many areas of science: it links the microscopic world of atoms and molecules to real, measurable quantities of substance. Helping students see this link clearly can build confidence and set them up for success across the curriculum.
Teaching the mole with confidence
STEM Learning has curated a number of resource collections to support teaching and learning of this tricky topic:
The BEST resources are particularly valuable, they identify the most common misconceptions that learners bring to lessons, such as confusing mass with amount of substance, or assuming that larger particles must mean more particles. Each resource includes diagnostic questions to reveal these misunderstandings, followed by classroom strategies and activities that help students reconstruct their knowledge. By actively addressing misconceptions, teachers can close learning gaps early and build a secure foundation for the more complex mole calculations that come later.
Taken together, these collections encourage teachers to move beyond rote calculation, using analogies, visuals and inquiry questions that make the scale of 6.02 × 10²³ more approachable and memorable.
Ideas for Mole Day
Mole Day is also a great chance to inject some fun into learning. Some ideas from the community include:
- Estimation jars: how many beans or rice grains in a container, linked to the idea of very large numbers.
- One mole of a substance: Ask your technician(s) [NICELY] to set up a collection of beakers containing one mole of different elements/compounds
- Creative projects: posters, mole-themed quizzes, or even mole-shaped cakes.
- Student-generated questions: asking learners to write and swap their own mole calculations.
Get involved
Whether you run a one-off activity or make Mole Day a whole-class event, it’s a chance to highlight one of chemistry’s most important and inspiring ideas.
Explore the original blog and the full set of resources above to start planning your own celebration.
How will you be marking Mole Day this year? What’s your favourite way to explain the scale of Avogadro’s number to students? Share your ideas with the community — we would love to see them.