How did Alessandro Volta’s battery produce an electric current?
The ingenuity people used in harnessing waterpower can be seen in this medieval-style mill. The waterwheel is turned by a stream and is connected to a shaft that leads into the building. At the other end of the shaft is a gear. The connection of a series of gears translates the power from the stream to a shaft that drives a millstone, which grinds flour from grain.
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Alessandro Volta’s battery, known as the voltaic pile, produced a continuous electric current by utilizing chemical reactions to generate electromotive force.1
The device consisted of alternating disks of two different metals—typically zinc and silver or copper—separated by paper or cloth soaked in an electrolyte, such as salt water. This arrangement functioned because the energy released by the chemical interaction between the metals and the electrolyte created a potential difference.12
Specifically, the battery relied on the difference in the degree of binding between electrons in the two metals. As chemical reactions occurred at the electrodes, electrons were effectively pushed through an external circuit, providing a steady flow of electricity. By stacking these pairs of disks, Volta created a reliable source of current that did not require recharging, fundamentally establishing the field of electrochemistry.21