Scanning tunnelling microscope, 1986.
© Science Museum / Science & Society Picture Library
Made by WA Technology of Cambridge, this was the first STM (scanning tunnelling microscope) to be produced commercially. The STM is a type of electron microscope which is used to show three-dimensional images of metal surfaces at the atomic scale. It is able to detect the roughnes of the surface of a sample, the presence of any defects, and the size and conformation of molecules and crystals. The microscope can also be used to analyse the surfaces of organic molecules such as DNA in order to determine their structure. The resolution of the image obtained with an STM is of the order of a nanometre, or 0.000000001 metre.