Medieval artisans were the first nanotechnologists

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Medieval artisans were the first nanotechnologists. They knew that by putting varying, tiny amounts of gold and silver in glass, they could produce the multicolored effects found in stained-glass windows. Large zinc oxide particles appear white, while at the Nanoscale they are clear. This property is used in newer clear sunscreens. The chemical reactivity varies as the size of the particle changes. The purpose of the experimental activity outlined in this module is to demonstrate the different rates of reaction caused by particle size. Why do properties change? One reason why properties of structures are different at the Nanoscale is because as particles get smaller, the ratio of surface area-to-volume of the structure increases. Most atoms are at or near the surface. Because chemical reactions take place on the surface of a particle, if there is an increased surface area available for reactions, the reaction can be very different. Where can nanotechnology be used in our everyday lives? Nanotechnology is becoming more and more prevalent and has the ability to affect all aspects of our lives; from clothing, cosmetics, computing and healthcare to futuristic ideas such as elevators to space. The study of materials behavior and properties can be manipulated to make more lightweight, robust structures and smaller, more efficient devices across a range of industries. Where is nanotechnology already being used? • Carbon nanotubes are being used in the sports industry to make lighter and more robust equipment such as tennis rackets and lightweight bikes. • Nanotechnology is used in surface coatings which have special properties like water, fire or scratch resistance, or are self cleaning e.g. in waterproof and stain- resistant clothing, paint, self-cleaning windows. • Face -creams and cosmetics also contain nanomaterials (also called liposomes/nanosomes), which help retain moisture and deliver active ingredients to cells. • Nanotechnology is applied in the miniaturization of computers and other electronics and in more powerful and efficient data storage techniques. • Nanoscience is applied in the development of faster and more sensitive medical testing devices and treatments. • Sun creams use nanoparticles of zinc oxide or titanium dioxide to absorb the harmful UV rays from the sun, while making the sunscreens appear ‘invisible’. Macro-sized particles are not transparent. • Nanotechnology can help the environment – advances in nanoscience are 269 Physicsal Science Department
producing more efficient solar cells and materials and devices which require lower operational energies. Nanoscience can also be used for water purification in developing countries. How do we make stuff using nanotechnology ? Broadly speaking, there are two approaches in nanotechnology for manufacturing: top-down This can be considered as the miniaturization approach. It is the main technique used in the electronics industry, to make smaller more powerful computers. It involves building something by starting with a larger component and

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