NANOTECHNOLOGY—TECHNOLOGY ON A MOLECULAR SCALE - Chemistry: Notable Research and Discoveries - page 50

ScanningTunnelingMicroscope
According to quantum mechanics, atoms do not tend to
have an exact position and velocity. Due to variations in mo-
tion, atoms can jump around, even to the extent of escap-
ing a container or passing through a barrier. This behavior
is not observed in everyday activities—macroscopic objects
contain so many atoms that the fl uctuations of a few indi-
viduals are unimportant, and, as described in the sidebar
on pages 20-21, the behavior of the group is predictable.
But quantum mechanical effects appear in objects the size
of atoms. A tennis ball will always bounce back when it hits
the net, but an atom may occasionally encounter a barrier
and continue through. Passage through a barrier is called
tunneling in quantum mechanics.
Developed in 1981 by Gerd Binnig and Heinrich Rohrer
at the IBM Zurich Research Laboratory in Switzerland, the
Scanning Tunneling Microscope passes an extremely thin
Researcher using a scanning tunneling microscope (Volker Steger/
Peter Arnold, Inc.)