Get ready to celebrate one of chemistry’s most iconic numbers! National Mole Day brings the microscopic world of atoms and molecules to life through fun, hands-on activities that explore how chemists measure, count and study things too small to see.
What Is a Mole?
A mole is a unit chemists use to count extremely tiny particles such as atoms and molecules. Just as a dozen means 12, one mole represents approximately 6.022 × 10²³ particles—a number known as Avogadro’s number. The date October 23, written as 10/23, gives Mole Day its name.
Featured Activities:
Atomic Target Practice
Investigate something you can’t see! Roll marbles beneath a covered board and map how they bounce off a hidden shape. Use the paths and deflections to determine the mystery object’s size and location—similar to how scientists study unseen particles.
The Heavy Count: Weighing the Invisible
Can you count a mystery collection without opening its container? Weigh sealed cups filled with crayons, pennies or individual grains of sand, then use a little math to estimate how many objects are hiding inside.
Color-a-Mole
Combine art and chemistry by weighing a crayon before and after creating your masterpiece. Calculate how much wax your drawing used—and discover whether you could ever color with an entire mole of wax!