-8. The sodium (1) and chlorine (2) atoms of the salt crystal are clearly indicated. The shading here and in later pictures has only a symbolic value: a darker grey only means that the probability is greater that an electron will be found there than in a place that is more lightly shaded. As to the oxygen molecules (3) moving in the air, their average speed at a temperature of 10° Centigrade (= 50° Fahrenheit) would be 470 meters per second (= 1,000 miles per hour) in reality. In the image that speed would be 10⁸ times greater, that is, more than 100 times the speed of light! In the inset the helical structure of the flagellum which could be recognized in -7 can no longer be seen, as again only hydrogen atoms are indicated, and all other atoms behind them (oxygen, carbon, and nitrogen) are left out. In the corner is one quarter of a hydrogen atom.

1 cm. in picture = 10^-8 cm. = 1A (angstrom unit).
Scale = 100,000,000:1 = 10⁸