Elementary school students learn that atoms are very, very small. Students are also taught that atoms (and molecules) are the fundamental constituents of the material world. Numerical values of their size are often given, but, nevertheless, it is difficult to imagine their size relative to one's everyday surroundings. In order for students to obtain a quantitative understanding of the size of atoms, we have considered this problem by asking the following question: namely, how many atoms are in a printed period (.)? In this paper the number of atoms in a period is determined, along with a discussion and an equation to determine the radius of an atom. A related discussion regarding the size of atoms can be found in Ref. 1.