» Copper Disk with Handle (0018)
Immagini
DESCRIPTION
Copper disk with insulated handle. This instrument was used as a convenient carrier of positive charge for making sparks or for charging capacitances (condensers).A common procedure required charging a disk of resin by rubbing it with cat's fur to make it negative. Then the copper disk covered with rubber or sealing wax was placed on the charged resin disk. By induction, positive charge appeared on the side next to the resin disk and negative charge on the far side. Upon touching the copper disk the negative charge was dispersed to ground. Now upon raising the copper disk the remaining positive charge appeared on its entire surface, ready for experiments like generating sparks. Since the resin disk holds charge for a long time, the copper disk could be positioned again on the resin disk and the experiments repeated. This application was explained in a physics book by A.Privat-Deschanel, translated by A.A.Pozzi [2]:
BIBLIOGRAPHY
- [1] G. Cantoni: Su alcuni principj di elettrostatica, Milano, Vallardi, 1873.
- [2] A.Privat-Deschanel - Trattato elementare di fisica ad uso dei Licei, degli Istituti Tecnici,... - versione italiana con molte aggiunte e note del dott. A.A.Pozzi - Fratelli Dumolard ed., Milano - II edizione (1882) - pag. 448
Dati Catalografici
| Data di costruzione: | --- |
|---|---|
| Data di carico: | 1835-05-25 |
| Nr. Inventario: | 849 (Generale dal 1874) 368 (Antico inv. Gabinetto Fis) |
| Costruttore: | Costruttore sconosciuto |
| Materiale: | rame, vetro |
| Dimensioni: | Diametro del disco: 18 cm; Manubrio: diametro 1 cm; lunghezza 23 cm |
| Conservazione: | ottimo |