In an atom, the proximity of the next empty track to the outermost filled track determines whether or not that atom can conduct electricity. If the next empty track is close by, the electrons in the outermost track might be able to jump up to it if they are given a jolt of energy from an outside source like a flash of light. When this happens, the electron that jumps is in a track with empty spaces, enabling other electrons to jump from other atoms and join it as it travels around the nucleus. Atoms with a full outside track which is very close to the next track are thus sometimes able to conduct electricity (specifically, at times when they are given a jolt of energy), and they are thus known as semiconductors.
In order to conduct Medal Day ceremonies properly, The Franklin Institute inquired after the marital status, proper name and title, and university affiliation of its award recipients. In addition, the secretary of the Institute made hotel arrangements for medal winners and invited them to bring guests. You can read the letters regarding Bardeen and Brattain's hotel reservations and itineraries by clicking on the thumbnails at right.
Letter to Brattain from Allen / (314 k);
Letter to Allen from Brattain (374 k);
Letter to Brattain from Allen / (515 k);
Letter to Ms. Gladys A. Scott, Secretary to Allen / (462 k);
Letter to Dr. John Bardeen from Allen (705 k);