## How Big?

Nanotechnology deals with the very smallest components of our world – atoms and molecules. Trying to understand just how small the nanoscale is can be very difficult for people. A nanometer is a unit of measurement for length just as you have with meters and centimeters. A nanometer is one billionth of a meter, 0.000000001 or 10-9 meters. The word nano comes from the Greek word for “dwarf.” The term nanoscale is used to refer to objects with dimensions on the order of 1-100 nanometers (nm).

To understand how small a nanometer is, we typically compare the nanoscale to objects that we know how big or small they are. Here are some examples:

- a human hair is about 60,000 – 80,000 nm wide
- a fingernail grows 1 nm per second
- a DNA molecule is 2-3 nm in wide
- A 2 meter person is 6 feet 6 inches tall or 2 billion nanometers

Another way to help in the understanding of the minuteness of a nanometer is to examine objects on a size scale. Follow this link to an interactive scale developed by our colleagues at Stanford University and McREL for their NanoLeap project. Use this scale to examine the size for a variety of objects - http://www.mcrel.org/NanoLeap/multimedia/Nanosize_me.swf .

Other useful resources to help understand size and scale include:

- Powers of Ten – explores the relative size of things from the microscopic to the cosmic (includes a Powers of Ten game from Nickelodeon Magazine) (http://powersof10.com)
- Cells Alive How Big video – explores size of objects based on the powers of ten (http://www.cellsalive.com/howbig.htm)
- Scale of Things poster available from the Department of Energy. ( http://science.energy.gov/bes/news-and-resources/scale-of-things-chart/)