Alessandro Volta is famous for inventing the pile but very few people know that he was the first to discover the phenomenon of thermoelectricity, by which electricity is generated by the junction of different metals kept at different temperatures or, inversely, thermoelectricity is generated when electric current passes through the same metals.
Volta observed that, by heating the terminals of a metallic arc, an electric tension settled in, and that the same disappeared upon arc cooling. Some time later, Thomas Johann Seebeck showed that thermoelectric currents arise by joining different metals kept at different temperatures; then Peltier discovered the reverse effect, i.e. that, by imposing the flow of a direct current in a similar bi-metallic circuit, a difference in temperature between the metal junctions can be observed.
These discoveries could have paved the way for devices for direct production of electricity from heat. But actually the only successful application was in thermocouples, simple devices for direct temperature measurement based on the Seebeck effect. Thermoelectricity received a strong impulse from the introduction of space technology.
The film tells about the historical development of applications based on this phenomenon, describing some of their peculiarities with simple experiments and exploring the possible research options to produce and use thermoelectric materials for industrial, space, and energy applications.