Baking powder submarine

In 1953 Benjamin and Harry Hirsch, two brothers in a cosmetics company, discovered that carbon dioxide gas bubbles produced in wet baking powder as part of the chemical leavening process could be used to make a toy submarine dive up and down in fresh water.

[1]: 34  Buoyed by the popularity of the first American atomic submarine USS Nautilus commissioned in that year, a million 4.5-inch (110 mm) plastic ship model prizes were produced by May.

A smaller 2.5-inch (64 mm) version was later produced to be used as a cereal box prize not requiring separate redemption by mail.

[1]: 35 The same principle of operation was later used for toy frogmen powered by baking powder in a small container on the foot of the figure.

However, some other cereal prizes were cartesian divers, which operated on a different principle and did not require baking powder.