Conceptual understanding of electricity: Galvanic cells


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Özkaya A. R. , Üce M. , Şahin M.

The Royal Society of Chemistry Chemistry Education Research and Practice - University Chemistry Education, cilt.8, ss.24-29, 2004 (ESCI İndekslerine Giren Dergi)

  • Cilt numarası: 8
  • Basım Tarihi: 2004
  • Dergi Adı: The Royal Society of Chemistry Chemistry Education Research and Practice - University Chemistry Education
  • Sayfa Sayıları: ss.24-29

Özet

In a recent letter to University Chemistry Education,Alan Goodwin comments on one of the conceptual questions (Question 15) involved in our article.First of all, we would like to thank Alan Goodwin for his valuable comments. He states that he is a little worried by Question 15 and our offered ëcorrectí answer. In his opinion, Question 15 and our offered ëcorrectí answer to it suggest that we believe that current between the electrode compartments will not flow along a conducting wire. We are aware of the fact that if a metal wire replaces the salt bridge in a galvanic cell the ammeter connected through the circuit may show a reading, but we also know that this current reading is very low (as also stated by Goodwin) compared to the current measured using a salt bridge. It is necessary to use a very sensitive ammeter to be able to measure such a low current. We could not measure it when we used an ordinary ammeter in the circuit. Therefore, during the construction of the question, we thought that this very low current could be ignored. Question 15 is very similar to the one involved in the article reported by Ogude and Bradley (Question 11).The only difference between the two is that the one reported by Ogude and Bradley replaced the salt bridge with graphite while our question replaces it with a piece of platinum wire. Ogude and Bradleyís ideas about this issue were probably similar to ours when constructing Question 11, since they offered the same alternative as the ëcorrectí answer, so we do not believe that it is necessary to correct either Question 15 or our offered ëcorrectí answer.