Overview of Shrinking

How do we shrink something? What happens to whatever's inside? May we shrink a larger machine down into its micro or nano version? Or must we organize small machines in entirely new ways? Shrinking alters things in unforeseen ways. Gravity affects small machines less for example. A flea jump dozens of times its height, but we cannot. How does smallness determine a system's operating speed, its power density, its output and overall efficiency?

Scaling laws are a simplistic indicator, of why nanotechnology may be extremely powerful even when compared with biology. Scaling laws let us compare the relative performances of systems having different scales to combine properties such as how a system's power relates to the system's volume giving us its 'power density.'

Consider a muscle inside a bee's leg. As we shrink the leg and muscles, strength decreases as the cross-sectional area of the leg and muscles decreases. A muscle's weight is proportional to its volume. Strength versus weight crudely indicates a muscle's power: length squared divided by length cubed or length to the minus one. Therefore, strength per unit weight improves ten times as our bee shrinks ten times smaller.

Consider gravity: A nanomachine, nearly a million times smaller than a flea, is entirely unaffected by gravity. We cannot compare directly strength and mass, but together both determine our shrunken system's performance.

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