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ERIC Number: EJ1024877
Record Type: Journal
Publication Date: 2013-Oct
Pages: 2
Abstractor: As Provided
ISSN: ISSN-0031-921X
Big Pile or Small Pile?
Branca, Mario; Quidacciolu, Rossana G.; Soletta, Isabella
Physics Teacher, v51 n7 p406-407 Oct 2013
The construction of a voltaic pile (battery) is a simple laboratory activity that commemorates the invention of this important device and is of great help in teaching physics. The voltaic pile is often seen as a scientific toy, with the "pile" being constructed from fruit. These toys use some strips of copper and zinc inserted in a piece of fruit to produce a low-intensity electrical current to power a digital device. In a voltaic pile of this type, the zinc acts as an anode while the copper acts as a cathode. The reduction reaction [i.e., 2H[superscript +](aq)+2e?H[subscript 2](g)] occurs on the copper (the cathode). The two electrons that are needed for the reduction are taken from the metal (copper), which remains positively charged, while the anode is the zinc, which is oxidized through the reaction Zn[superscript °](m)?Zn[superscript +2](aq)+2e, and the two electrons remain on the metal, which is negatively charged. If the two pieces of metal are connected by an external conductor, electrons flow from the zinc to the copper. The electromotive force of this system is about 0.76 V, which is the reduction potential of zinc, as can be found in the table of standard reduction potentials.
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A