http://www.exploratorium.edu
DID YOU KNOW?
...that your fingernails grow at the rate of about one nanometer per second?
A nanometer (nm) is one-billionth of a meter-about the width of an average
molecule. For comparison, a human DNA molecule is about 2.5 nanometers wide,
while a strand of human hair can be 50-100,000 nm in diameter.