These are silicate garden (also known as chemical garden) experiments with potassium silicate aqueous solutions as media. Nickel and Fe(III) silicate plants were grown in a 10% solution, whereas cobalt chloride was dropped in a 15% solution of potassium silicate. Of the three transition metal chlorides, ferric chloride produces the most dramatic, chaotic and unpredictable results. With cobalt chloride, the growth is rather fast - I had to slow down the video by a factor of 2 to make it pleasant to watch. Some general information on the silicate (or chemical) garden experiment: you start by preparing an aqueous solution of sodium silicate. Then you drop crystals of a transition metal salt. As the salt starts dissolving, an insoluble silicate of the transition metal is formed, and it produces a tubular membrane. This tubular structure grows upwards because the liquid it contains has a lower concentration of the sodium silicate than the concentration in the surrounding liquid. While this sounds simple enough, the phenomena present in the experiment arent all quite so well understood, and there has been a lot of interesting research done into the humble little chemical curiosity: Structural precipitates: The silicate garden type by Hazlehurst, 1941 pubs.acs.org/doi/abs/10.1021/ed018p286 Studies of the growth of “silicate gardens” and related phenomena by Coatman et al., 1980 Three-Dimensional Morphological Chirality Induction Using High Magnetic Fields in Membrane Tubes Prepared by a Silicate Garden Reaction by Duan et al., 2005 Many other publications exist. It is interesting that the results of the experiment may vary a lot, depending on the concentration and temperature of the solution, the salt used and the morphology of the crystal or aggregate of the salt. And other factors.
Posted on: Sun, 11 Jan 2015 05:55:20 +0000