Bubbles are made of two components, soap and water, though simple, these chemical components create what is known as film. Film is defined as the layers of a bubble, there is an outer and inner shell of soap, as well as a layer of water molecules sandwiched between them. This unique combination allows air to remain trapped inside when it is formed into a spherical shape. The structure of a bubble is determined by surface tension, which is what holds a bubble together creating equilibrium forces surrounding the bubble. Surface tension is defined as the force between liquid molecules at the surface or edge of a liquid causing the surface to act like an elastic sheet. This photo demonstrates the behavior of a bubble in a cylindrical structure. The behavior shows a concave surface. As the spring stretches, soap stabilizes the liquid through a concept called the Marangoni effect. This effect occurs when a liquid flows away from areas of low surface tension to those of high surface tension. Therefore in locations in which the film is stretched, the surface concentration of soap decreases, this causes the surface tension to in turn increase. Thus, the area of increased surface tension is centralized to the farthest area from the edges of the spring, causing a squeezing force seen in the concavity of the film.