Everything is unique at the atomic scale, but measuring details at this level is normally very difficult to do. The resolution of a normal optical microscope is limited by properties of the light it uses to form images. A number of different microscope technologies have been invented to go beyond this limit. One of these, the scanning probe microscope, can also be used to move atoms around!
We brought an atomic force microscope to the exhibition. This tool uses a remarkably simple technique to measure the surface profile of an object with atom scale precision. The YouTube video below outlines how it works:
Moving single atoms around to clone a specific structure is incredibly difficult and time consuming. One of security tags contains around one thousand-trillion atoms (10^15 or 1,000,000,000,000,000). It would take a scanning probe microscope roughly the age of the universe to produce an identical clone of a tag!
In the next element of the exhibition we look at a simple electronic device that is capable of reading a unique fingerprint from atom-scale imperfections.