Although breathing is a universal activity among physicists (and others), few have bothered to estimate the number of molecules inhaled in a single average breath. Some simple calculations and comparisons related to this phenomenon are provided to improve students' appreciation of the awesome numbers related to Avogadro's number. (JN)

Presented are two cases of simple geometrical calculations involving the large numbers of atoms that are encountered in two ordinary situations. Included are questions about the spatial implications of the genome and a mole of hydrogen. (CW)