Soap allows water to bubble

Water molecules stick together too well to produce a bubble. The attraction between them prevents the water from spreading to produce the surface of the bubbles, but soap pushes the molecules apart, stretching the water into a thin film.

Asoap bubble’s surface is a sandwich of soap and water. Without soap, water cannot produce bubbles, as surface tension holds the molecules together, preventing the water from spreading into a thin film. The surface tension is due to the fact that all water molecules involve electric charges allowing them to attract the surrounding water molecules. Under the water surface, water molecules attract each other from all angles, but the molecules near the surface can only move downwards. The attraction is so powerful that you can pour more water into a glass than it can actually hold, without any water spilling out. When you add soap to the water, the soap molecules will be located on the surface, squeezing in between the water molecules, so surface tension is reduced. A thin film of water can now be produced, as the soap settles on both sides of the water, keeping down the tension. You make a bubble by blowing at the film. Normally, the bubble will soon become unstable, as the water evaporates, making the film thinner, but if you add glycerin, it will bind to the water, curbing evaporation and making the bubble stronger.