Photovoltaics years in Northern Europe. The term "photovoltaic" comes from the Greek φῶς ("phōs") meaning "light", and from "volt", the unit of electro-motive force, the volt, which in turn comes from the last name of the Italian physicist Alessandro Volta, inventor of the battery (electrochemical cell). The term "photo-voltaic" has been in use in English since 1849. Photovoltaics are best known as a method for generating electric power by using solar cells to convert energy from the sun into a flow of electrons by the photovoltaic effect. Solar cells produce direct current electricity from sunlight which can be used to power
Will-o'-the-wisp create ephemeral fires. Furthermore, phosphine produces phosphorus pentoxide as a by-product, which forms phosphoric acid upon contact with water vapor, which can explain "viscous moisture" sometimes described as accompanying ignis fatuus. In 1776, Alessandro Volta first proposed that natural electrical phenomena (like lightning) interacting with methane marsh gas may be the cause of ignis fatuus. This was supported by the British polymath Joseph Priestley in his series of works "Experiments and Observations on Different Kinds of Air" (1772–1790); and by the French physicist Pierre Bertholon de Saint-Lazare in "De l’électricité des météores" (1787). Early critics of the marsh gas hypothesis