A soap bubble is created in the same way that detergents reduce the surface tension of water.

Pure water molecules attract each other strongly and will always pull together to form a droplet rather than a film. Detergent molecules reduce the attraction between them but the water molecules retain enough attractive force to create a film.

When a child blows a bubble, the film stretches and forms a sphere. As the water evaporates, the bubble bursts.

Rainbow colours The ‘rainbow’ in a bubble is caused by light reflecting on the surface.