Imagining differences in scale can be very easy (a softball is bigger than a baseball) or very difficult (how can we imagine the size of a galaxy?). It is perhaps most challenging to build conceptual frameworks for objects that are too small to see. In this chapter, students identify and compare the scale of different objects, and define nanoscale and nanoscience. The teacher introduces the history and applications of nanoscience. This free selection also includes the Table of contents, Tips for Using this Book, and the Index.