Researchers working in nanotechnology apply scientific and engineering principles to make and utilize very small things. Just how small is "very small"? A nanometer is one-billionth of a meter. Particles in the "nanoscale" have dimensions between approximately 1 and 100 nanometers (nm). Made of just a few atoms, these objects are too small to be seen with the naked eye. In fact, they are barely visible through a good optical microscope and thus require specialized microscopes.

Since the emergence in the early 1980s of scanning tunneling microscopes, which are capable of visualizing objects at the atomic level and transfer the image graphically onto a monitor, scientists and engineers have been trying to manipulate atoms and molecules into precision nanoscale tools. The ability to see the structure of different nano-sized objects has opened up enormous possibilities. To create nanoparticles and nanodevices, researchers follow the same process that biological cells use to create structures. The process, called self-assembly, involves arranging atoms and molecules into larger nanostructures—or building from the bottom up. This contrasts with the "top-down" approach of breaking down large pieces of material and ending up with a smaller structure.

Researchers manipulate individual atoms by controlling their ability to chemically bond. This means disturbing electrons that create the bonds. Subatomic particles, which include electrons, protons, and neutrons, follow the rules of quantum mechanics. Thus, the properties and behavior of substances at the nanoscale can sometimes contradict classical physics and yield unpredictable results. For example, gold normally melts at 1063º C (1945º F). But gold particles smaller than 10 nanometers in size melt at a much lower temperature. In the same way, some materials known for their insulating properties can, on a much smaller scale, be turned into ultra efficient conductors of heat or electricity if properly harnessed.

Researchers are experimenting with substances at the nanoscale to learn about their properties and related phenomena. Based on what they discover, they can determine possible applications. Already, certain nanomaterials make tennis rackets and bicycles both lightweight and stronger than steel; nanocoatings make eyeglasses easier to keep clean and harder to scratch, and give fabrics water and stain repellency. What's more, nanotechnology has the potential to transform numerous industries, including aerospace, agriculture, energy, environmental improvement, information technology, and medicine. For example, researchers may one day deploy nanorobots to rebuild the thinning ozone layer, purify drinking water, and clean up hazardous waste sites.

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