Effect of Agar Bridge Composition on the CuSO4 Diffusion Rate

Kazuhiro SAWADA* and Noriyuki MORITA

Department of Practical School Education, Tennoji Campus, Osaka Kyoiku University; 4-88, Minamikawahoricho, Tennoji-ku, Osaka-shi 543-0054 Japan

The concentration of agar and KCl in agar bridge may be respectively divided into three groups according to textbooks on chemical experiment. Preliminary experiment was done to examine the difference in the property of the agar bridge by the composition of the agar bridge as follows. Each of the solutions of CuSO4 and ZnSO4 in water was poured into the opposite side of agar bridge, which was prepared with various compositions in a test tube. Then the diffusion velocity of CuSO4 in agar bridge was measured. The obtained velocity in the lapse to time difference have showed a change with the composition of agar bridge. If KCl would have changed the structure of agar gel as well as sugar, the change of velocity by KCl concentration could be consistently explaned. But the one by agar concentration could not be explaned. As the effect of KCl upon the structure of agar gel has been in the stage of hypothesis, various experiments should been systematically done to explane the mechanism of the differencein the diffusion velocity of CuSO4.

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