In George M. Whitesides' line of work things are measured in nanometers. A nanometer is one-billionth of a meter, and to get a sense of how small that is, forget about analogies to the width of a human hair or the head of a pin. The "nanoscale" has nothing to do with familiar items. You need to think about a place where objects-including the devices being worked on by Whitesides and others-are only slightly larger than atoms.

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