PUBLIC HEALTH ENGLAND / SCIENCE PHOTO LIBRARY PUBLIC HEALTH ENGLAND / SCIENCE PHOTO LIBRARY
This telephone, known as a trimphone, is a British model that was designed in the 1960s. TRIM stands for tone ring illuminator model, as the telephone had an electronic ringer and a luminous dial, both highly innovative features at the time. The luminous dial contained the radioactive element tritium, which allowed light to be emitted from the dial without using electricity. The tritium undergoes beta decay, a process where high-speed electrons (beta particles) are released as it changes from one isotope to another (elements with atoms that vary in their neutron numbers). The emitted beta particles are then used as the illuminating energy source in the trimphone.
Model release not required. Property release not required.