Injecting saturated sodium silicate solution into transition metal salt solution causes precipitation of metal silicates in downward-growing structures—the reverse of the well-known “chemical garden” phenomenon. The macroscopic structures created by this precipitation are highly visually distinct (budding, fracturing, jetting, and popping, with intermediate behaviors), but are also highly dependent on conditions: salt concentration, salt identity, silicate solution injection rate, and needle size. In-depth physical analysis of this behavior has been impeded by the fact that multiple experimenters often disagree which particular behavior they are seeing under any particular set of conditions. We present an empirical analysis of this behavior that allows unambiguous identification of the precipitation "regime" independent of experimenter's judgment.

Empirical analysis of "reverse chemical garden" precipitation behaviors

251st National Meeting (2016)

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