pH 4.5 · Limestone
This simulation dissolves a carved cemetery gravestone over accelerated centuries, exactly as acid rain does in real churchyards. Calcium carbonate reacts with the sulfuric and nitric acid that atmospheric pollution creates, and with the mild carbonic acid present in ordinary rainwater, converting solid stone into soluble calcium salts that wash away with every storm. Lower the rainfall pH or raise the rainfall frequency and watch the carved inscription soften, pit and eventually blur into illegibility, while the running years-elapsed and legibility readouts track exactly what field researchers measure on real dated gravestones to reconstruct historical rainfall acidity. Switch between limestone and marble to see why marble headstones from the same era read far more clearly today.