EASY AND SIMLER PROJECTS ON ELECTRO-WRITING-  Dip a filter-paper in a solution of sodium sulphate containing a little amount of phenolphthalein.  Now keep this filter paper on a copper plate.

Join the positive pole of a battery to the copper plate with the help of a copper wire.  Take a long flexible insulated wire and  attach one end to the negative pole of the battery and attach the other with a metallic stylus.

Write  anything on the blotting paper by pressing this stylus.   We will get the writing material which we had wrote  in red colour.

( This process can be used to test the negative or positive pole of a battery.  The red colour will be  get only by negative pole wire).

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