Potassium dioxide, KO[subscript 2], (potassium superoxide) is an important compound owing to its ability to react with carbon dioxide to produce oxygen. This unique ability is employed to design rebreathing devices for submarines, space vehicles, and space suits. "Rebreathers" for firefighters and miners have also been designed using potassium superoxide. We provide instructions for performing two classroom demonstrations: (a) The demonstration of potassium superoxide's ability to react nearly quantitatively with carbon dioxide, and (b) the paramagnetism of potassium superoxide. Five confirmatory experiments are described in support of the first demonstration. (Contains 2 figures and 12 notes.)