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Introduction

Mohamed Gad-el-Hak
Virginia Commonwealth University

How many times when you are working on something frustratingly tiny, like your wife’s wrist watch,
have you said to yourself, “If I could only train an ant to do this!” What I would like to suggest is the
possibility of training an ant to train a mite to do this. What are the possibilities of small but movable
machines? They may or may not be useful, but they surely would be fun to make.

(From the talk “There’s Plenty of Room at the Bottom,” delivered by Richard P. Feynman at the
annual meeting of the American Physical Society, Pasadena, California, December 1959.)

Toolmaking has always differentiated our species from all others on Earth. Aerodynamically correct
wooden spears were carved by archaic Homo sapiens close to 400,000 years ago. Man builds things con-
sistent with his size, typically in the range of two orders of magnitude larger or smaller than himself, as
indicated in Figure 1.1. Though the extremes of length-scale are outside the range of this figure, man, at
0
slightly more than 10 m, amazingly fits right in the middle of the smallest subatomic particle, which is

Diameter of Earth Astronomical unit Light year

2 4 6 8 10 12 14 16 18 20
10 10 10 10 10 10 10 10 10 10
meter

Voyage to Brobdingnag

Voyage to Lilliput
meter
−16 −14 −12 −10 −8 −6 −4 −2 0 2
10 10 10 10 10 10 10 10 10 10

Diameter of proton H-Atom diameter Human hair Man

Nanodevices Microdevices Typical man-made
devices

FIGURE 1.1 Scale of things, in meters. Lower scale continues in the upper bar from left to right. One meter is 10 6
9
10
microns, 10 nanometers, or 10 Angstroms.

1-1

© 2006 by Taylor & Francis Group, LLC