The document describes properties of acids and bases through a series of experiments. It tests acids and bases by touching them to the finger, measuring pH with litmus paper and a pH key, and observing reactions with phenolphthalein, bromothymol blue, magnesium, and baking soda. Acids are sour and not slippery, turn litmus paper red, and react in characteristic ways. Bases are bitter and slippery, turn litmus blue, and react differently. The document also discusses pH, the logarithmic scale used to measure hydrogen ion concentration, and provides examples of calculating pH from hydrogen ion concentration and vice versa.