A nanometer is a unit of measure. Just like inches, feet and miles. By definition a nanometer is one-billionth of a meter. A meter is about 39 inches long. A billion is a thousand times bigger than a million, as a number you write it out as 1,000,000,000. That is a big number and when you divide a meter into one billion pieces, well that is very small. So small you cannot see something a nanometer in size unless you use very powerful microscopes like atomic force microscopes.

A nanometer is used to measure things that are very small. Atoms and molecules, the smallest pieces of everything around us, are measured in nanometers. For example a water molecule is less than one nanometer. A typical germ is about 1,000 nanometers. We can measure even larger things in nanometers, so a hair is about 100,000 nanometers wide. That is a lot of nanometers! Shaquille O’Neal, a very tall basketball player, is 2,160,000,000 nanometers tall.

Inside of your computer are tiny switches that are only 100 nanometers wide. About 1,000 of these switches can fit across the width of a single hair. Modern computers have about 100,000,000 switches packed inside, stacked one on top of another. We use nanotechnology to make these tiny switches.

And a lot of important things happen at the nanometer scale. We can think of the smell of freshly baked cookies and that is something that happens on the nanometer scale. The molecules that are released from the cookie when it bakes are less than a nanometer in size and so they are carried through the air to our noses because they are so small. Gravity does not have much of an effect on them and so they float along. They reach our noses and when they are very very close, less than a nanometer away, we can smell them.