Research Information System
CHEMISTRY: BULGARIAN JOURNAL OF SCIENCE EDUCATION, vol.15, no.2, pp.101-108, 2006 (Journal Indexed in SCI Expanded)
One of the most difficult subjects for students is the concept of
oxidation-reduction. The terms .oxidizing. and .reducing agent. are hard to
understand and usually mixed-up by students. Electrochemistry experiments
could be helpful in making easier to understand this subject. There are many
experiments that demonstrate electrolysis phenomena. However, the experiments
we propose are simple, cheap and could be applied in any level of chemical
education starting from a kindergarten up to the university level. Electrochemical
writing is an electrolysis experiment which shows writing with an electrode
(metal) on a paper soaked with an appropriate electrolyte solution in a
close current circuit. For performing electro-printing experiments, various coins
and other metallic objects are collected. Then, a square piece of aluminum foil
is cut and placed on the top of a rubber surface (rubber sheet). Quantitative
(smooth) filter papers are placed on the aluminum foil and soaked with different
kinds of solutions: aqueous solutions of ammonia, potassium hexacyanoferrate(
II), potassium tiocyanate, potassium iodide or solutions of sodium
sulfate with different acid-base indicators (including natural red cabbage
indicator).