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Nanotechnologies Nanotechnology is a relatively new field of science that makes more headlines every year. It is a field that focuses on the small --the extremely small. In nanotechnology, people manipulate atoms and molecules to make new things. Those things can be materials or devices. Throughout history, people have made new things from altering or combining substances that already exist. But nanotechnology works the opposite way. In nanotechnology, researchers develop a substance from the small to the large by manipulating the basic building blocks of matter. The result could be miniature materials or devices that have completely unique properties. Science of the small The basic building blocks of nanotechnologies are atoms and molecules. All substances are made up of molecules. A drop of water, for example, is made up of millions of water molecules. If you were to keep dividing the drop into smaller droplets, you would end up with one molecule. That one water molecule would have the same properties as the drop of water. 
Molecules are made of atoms held together by chemical bonds. The water 590
molecule consists of two hydrogen atoms and an oxygen atom. Diamonds are made up of a molecule of carbon atoms bonded together. Salt is made of the sodium chloride molecule, which is one sodium atom bonded to one chloride atom. Atoms and molecules are so small that a new prefix was coined to measure them: nano. The prefix "nano" comes from the Greek word for dwarf. Nano represents one billionth and so one nanometer is one-billionth of a meter. That's about the size of one strand of the width of your hair split into about 50,000 pieces! It's also about the size of ten hydrogen atoms. Things on the nano scale are generally between 1 and 100 nanometers. Proteins in our bodies, viruses, and some particles in the air are nano sized. 
Nanotechnology is not about simply making devices smaller. The field uses the fact that nano size materials can have different properties than their larger counterparts. Color, hardness, melting point, and conductivity are all some of the properties that can change as the material become nano sized. One physical characteristic that can lead to these changes is the increased ratio of the surface area to volume. Surface area is all the area that is on the outside--surface--of the material. Volume is the amount of three-dimensional space taken up by a material. As a material shrinks, its surface area increases compared to its volume, In the nano size, this ratio can increase dramatically, which can lead to different reactions. Gold nano particles, for example, can appear a reddish color and turn liquid at room temperature. It is the arrangement of the atoms and molecules that gives materials its properties. Diamonds and the lead of pencils (graphite) are both made of up carbon molecules. In diamonds, the arrangement and bonds of the carbon atoms make it hard and clear. Graphite is dark and relatively soft. If researchers can pluck individual atoms and decide how to arrange them, they can determine the property of the material. One nano scale material that was discovered in 1991 is also made of pure carbon. Carbon nano tubes are threads of carbon and the arrangement of its carbon makes it light, flexible, and stronger than steel. 591
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