AS WITH MANY THINGS that are invisible and difficult to understand—think subatomic particles such as the Higgs boson, muons, gluons, or quarks—any discussion of nanoparticles quickly shifts into the realm of metaphor and analogy. People working in nanoscience seem to try to outdo each other with folksy explanations: Looking for a nanoparticle is like looking for a needle in the Grand Canyon when the canyon is filled with straw. If a nanoparticle were the size of a football, an actual football would be the size of New Zealand. A million nanoparticles could squeeze onto the period at the end of this sentence. But what is a nanoparticle? The very simplest explanation is that a nanoparticle is a very small object. It can consist of any bit of matter—carbon, silver, gold, titanium dioxide, pretty much anything you can imagine—that exists on the scale of nanometers. One nanometer equals one-billionth of a meter.
more from Heather Millar at Orion Magazine here.