Hey Markus, I was thinking about your experiment here a little more in depth and why not try and run the voltage up in steps of 0.5vdc @ 150mA since you are using a regulated power supply?

I think you will get a far more revealing scatter plot, I'm just suggesting this because the substrate you are using (silver nitrate,) is electrically conductive and has the same potential difference as the conductors themselves.

Well, I guess the current is proportional to the size of the fractal. The size or better the area of a fractal is difficult to measure, current not. I also will try tin(II) chloride.

Yeah, that's why I suggested the stepped current, you may also want to use another petri dish as a control using silver bromide and liquid ammonia as it will make small uniform crystals ( they will will look like small cubes <1 micro meter)

Oh, also I wanted to commend you for this branch of research, it's about time we stop testing on animals. Good on ya! 

Very interesting take on Tollens' reagent. Usually this is done to determine the presence of an aldehyde and keytone functional groups, it looks like the addition of an electrical current has caused a redox reaction at the anode (the blue precipitate,) did you notice how the brownish silver oxide conjoins with the blue precipitate?

Looks like there might be some dissimilar metals in the silver wire you are using, try putting a few drops of NAOH (sodium hydroxide) in your petri dish the next time and watch what happens.

Hi David, I took the experiment from here: http://agris.fao.org/aos/records/US201300310747?output=xml

A great book by the way.

I noticed that the brownish silver oxide conjoins with the blue precipitate and thought this could be a first idea how to study different chemicals preventing the crystals to grow further (chemotherapeutic agent). The idea is just a few days old, I need to experiment further and collect more data. Will add a few drops NaOH next time and see what happens.

Thanks,

Markus