» Beccaria/Faraday Pit (well) (0163)

Immagini

DESCRIPTION

Exhibit 163 is the well of Beccaria and of Faraday for demonstrating the distribution of charge on metal. It consists of a metal cylinder mounted on a sturdy base with three legs at 120Â°. In the center of the lid there is an insulated handle to which is attached a metal sphere. At the base of the cylinder there is a hook to which an electroscope can be attached for determining the presence of charge.In the experiment the sphere is charged (let's say positive) and two choices are made.

In the first, the charged sphere is inserted into the cylinder without touching it, the positive charge on the sphere appears on the outside of the cylinder, and the pith balls inside adhere to the sphere. On the inside surface of the cylinder there is an amount of negative charge which equals the positive charge on the sphere. If now one touches the outside surface of the cylinder the positive charge disperses to ground, but the negative charge equal to the positive charge on the sphere remains. If now the sphere is retracted, this negative charge rushes to the outside and the cylinder is now charged negative.

In the second choice, the charged sphere is allowed to touch the inside of the cylinder and the cylinder is now charged positive and the pith balls fall away from the sphere. When the now discharged sphere is retracted, the cylinder remains charged positive.

ISCRIZIONI

Su una etichetta attaccata alla base: G.B.Paravia/Torino/materiale didattico scientifico

BIBLIOGRAPHY

[1] Eligio Perucca, "Fisica Generale e Sperimentale", Vol II, Pag. 440

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