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Frothy Foam

In this dramatic demonstration, potassium iodide catalyses the decomposition of hydrogen peroxide to oxygen and water.This is an exothermic reaction and water is produced as steam. Food colouring and washing up liquid mixed in with the hygrogen peroxide create coloured fountains of oxygen bubbles during the reaction. A glowing splint can be made to relight in the bubbles, showing that oxygen is present. This is an adaptation of the ‘elephant’s toothpaste’ demonstration.

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