Soap and the death of a bubble bath

[Antigen]

Why do the bubbles all disappear in my bubble bath after I lather up with a bar of soap?

Bubble bath = liquid soap, so why would the addition of more soap ruin my bubbles?

[antechinus]

This is similar to a recent thread about the foaming power of various detergents.

Bubble bath has detergents that are high foaming. The bubble films are made up of a layer of detergent molecules all the same size on either side of a thin film of water. The molecules have a water-loving head and water-hating tail so they all end up pointing in the same direction to form either side of the film.

When you introduce different types of detergents, such as soap, then there are molecules are a slightly sifferent size and shape that want to get into the film. The ordered layers of detergent moleculaes are disrupted by the other detergent and the bubbles cannot form as easily.