Bath bomb

A bath bomb causing bathwater to fizzle

Bath bombs are hard-packed mixture of dry ingredients which effervesces when wet. They are used to add essential oils, scent and colour to bathwater. They are a form of bath fizzies.

Composition

Bath bombs' primary ingredients are a weak acid and a bicarbonate base. These are unreactive when dry, but react vigorously when dissolved in water to produce their characteristic fizzing over a period of several minutes; carbon dioxide bubbles on bathers' skin gives a tickling sensation some find pleasant. A common chemical mixture is citric acid and sodium bicarbonate:

C₅H₇O₅COOH + NaHCO₃ → C₅H₇O₅COO⁻Na⁺ + H₂O + CO₂

The other ingredients in bath bombs can vary considerably. Most have scented ingredients — such as essential oils — in their composition to impart a pleasant fragrance to the water, and some are brightly coloured.

Production

LUSH brand bath bombs on display in a shop.

Bath bombs are generally spherical but can be found in a variety of shapes, such as tablets or lumps. Shops offer a wide range of bombs, but they can also be made at home.

References