Distances and Sizes

The Machinery of Life,
by David Goodsell.

One of the things Russ Hobbie and I added to the 4th edition of Intermediate Physics for Medicine and Biology is an introductory section about distances and sizes in Chapter 1 (pages 1–3). Our goal is to introduce the relative sizes of different biological objects (cells, bacteria, viruses, etc.). We try to provide something similar to what you would find in Morrison’s book Powers of Ten or in Goodsell’s book The Machinery of Life. The section also serves as a nice way to introduce many of the topics developed in more detail later in the book, and allows students to practice the valuable skill of making back-of-the-envelope estimates, such as estimating the number of hemoglobin molecules in one red blood cell. We hope you like it.