A nanometer is a billionth of a meter. A DNA molecule is 2 nanometers in diameter. Protein
molecules are about 10 nanometers in diameter. A human hair is 100,000 nanometers in diameter.
But what is a nanometer and how does it relate to technology? Nanotechnology is defined as the
understanding and control of matter at dimensions of roughly 1 to 100 nanometers, a scale at
which unique properties of materials emerge that can be used to develop novel technologies and
products. At the nanoscale, the physical, chemical, and biological properties of materials differ
from the properties of matter either at smaller scales, such as atoms, or at larger scales that we
use in everyday life such as millimeters or inches. Nanotechnology involves imaging, measuring,
modeling, and manipulating matter only a few nanometers in size. Gold nanoparticles are made
of the same material as in jewelry. But when light interacts with particles of gold, different colors
are reflected. The different colors can be used in simple medical tests to indicate infection or
disease. Metals such as copper become extremely rigid at the nanoscale, rather than bendable as
in copper wires seen in everyday use.