Ion Drift Velocity

Sharon Elsdon


I was wondering if anyone could help me.
Our Physics A Level teacher has asked for an ion drift velocity experiment which involves a piece of filter paper as big as a microscope slide saturated in ammonium hydroxide. Then a dress pin is attached either end with a croc clip. A piece of potassium permanganate is placed in the middle and a current is put through it.
On the video they shared with me I can see the drift occurring and something building on one of the dress pins. What would this be? I can hazard a guess but want to be sure.

I also wonder if anyone has any good experiments that they carry out with their A Level students for ion drift velocity?