Just how small is “nano”? In the International System of Units, the prefix “nano” means one-billionth, or 10-9 (0.000000001); therefore one nanometer is one-billionth of a meter. It’s difficult to imagine just how small a scale that is, so here are a few examples to put it in perspective:

• A sheet of paper is about 100,000 nanometers thick
• A strand of human DNA is 2.5 nanometers in diameter
• The smallest microprocessor transistor gate oxide thickness is 2.5 nanometers
• A cell’s membrane is 6 to 10 nanometers in thickness
• There are 25,400,000 nanometers in one inch (alternatively, there are 10,000,000 nanometers in a centimeter)
• A human hair is approximately 80,000 to 100,000 nanometers wide
• A single atom of gold is roughly 1/3 of a nanometer in diameter
• One nanometer is about as long as your fingernail grows in one second
• One nanometer is roughly the thickness of a carbon nanotube

The infographic below has three examples of the size and the scale of nanotechnology, showing just how small things at the nanoscale actually are. Source: http://www.nano.gov/nanotech-101/what/nano-size http://en.wikipedia.org/wiki/Orders_of_magnitude_(length)