- Problem 1
How many fundamental regions are there in one face of a speck of salt?
(With a ruler, we can estimate that face is a square that is cm on a side.)
Each fundamental unit is cm, so there are about such units. That gives , so there are something like (three hundred million) units.
- Problem 3
Give the locations of the atoms in the diamond cube both in terms of the basis, and in Ångstroms.
In terms of the basis the locations of the corner atoms are , , ..., . The locations of the face atoms are , , , , , and . The locations of the atoms a quarter of the way down from the top are and . The atoms a quarter of the way up from the bottom are at and . Converting to Ångstroms is easy.