The length of objects in life is about 1mm, including the thickness of blades, membership cards, business cards, 1 dime, credit cards, the diameter of rapeseed, the width of sesame seeds and so on.

Sometimes it is called nanometer in atomic physics, that is, 10-9 meters (65438+ billionth of a meter). Like centimeters, decimeters and meters, it is a unit of measurement for length. It is four times the size of an atom and less than the length of a single bacterium. A single bacterial microorganism is invisible to the naked eye, and the diameter measured by a microscope is about five microns, which is five thousand nanometers.