Some of the most interesting properties when particle gets converted to nano scale are substances which usually stop light become transparent (copper); it becomes possible to burn some materials (aluminum); solids turn into liquids at room temperature (gold); insulators become conductors (silicon). A material such as gold, which does not react with other chemicals at normal scales, can be a powerful chemical catalyst at nanoscales. These special properties which we can only see at the nano scale are one of the most interesting things about nanotechnology.