抄録
Microorganisms in water, when exposed to a sheet of rice paper, feed and deplete its starch sources and upon being introduced to iodine solution the rice paper failed to develop the expected deep blue black colour. Chlorination of sample water from pond and distilled water using the sodium hypochloride solution (NaClO) from the electrolysis of brine in an improvised device yielded the expected deep blue black colour of the rice paper with iodine solution due to disinfection of microbes. The oxidizing ability of chlorine was observed to be due to its bleaching action on bromothymol blue, 'Olong' tea and methylene blue solutions to colourlessness and the purple coloured iodine layer in hexane. These characteristic properties of chlorine were successfully investigated by grade 11 students of a Japanese high school in environmental science lessons.
