Scanning Tunneling Microscope
A probe is moved back and forth across the surface of a sample. When electrons jump, or tunnel, across the gap between the sample and the probe, an electric current is produced. A computer uses data about changes in the probe's position to produce an image of the sample's surface. Interpreting Diagrams How is the distance between the probe tip and the sample kept constant?
Scanning tunneling microscope
Modern scanning tunneling microscopes produce images of metal samples or biological specimens such as DNA.