Although he is best known as an American statesman, Benjamin Franklin also made important
contributions to electrical science in the mid-18th century. At the time, the Leyden jar, the first
capacitor, had just been invented, and Franklin performed experiments to determine the source of the
spark and shock that occurred on discharge of the jar. In these experiments, he used Leyden jars and
Franklin squares (parallel-plate capacitors) that could be disassembled and reassembled. These
devices later became known as dissectible capacitors. One of the more interesting results Franklin
obtained was that an electrified capacitor containing a dielectric could be disassembled, the
electrodes discharged, and the capacitor reassembled without sacrificing its ability to produce a
spark and shock. This result is contrary to what one expects from today’s theory for capacitors
involving ideal dielectrics (those possessing polarization and no other special properties such as
surface effects): al…