Small-Scale Construction
Some scientists and engineers think of atoms and molecules as construction materials for building very small objects.
The field of science called nanotechnology is named for a unit of measurement—the nanometer. A billion nanometers (109 nm) can fit in one meter. The diameter of a human hair is about 80,000 nm. Scientists and engineers who use nanometers as measuring units are building miniature versions of objects such as motors.
There are two general methods for building any object. You can start with more material than you need and shape the object by removing matter or you can build up the object from smaller pieces. When you shape your nails with an emery board, you are using a top-down construction method. When you see “some assembly required” on the side of a box, the manufacturer expects you to use a bottom-up method of construction.