Soap film
![Figure 1: Organisation of surfactants at both surfaces of the soap film](/Images/godic/202502/11/SchemeSoapFilm2512.png")
![Figure 2: Marangoni surface forces due to inhomogeneities in surfactants concentration. The arrows represent the force direction](/Images/godic/202502/11/MarangoniInSoapFilms2512.png")
![Figure 3: thin film interference in a soap bubble. Notice the golden yellow colour near the top where the film is thin and a few even thinner black spots](/Images/godic/202502/11/Thinfilmbubble2513.jpg")
![Figure 4: Picture of a film taken during its generation. The film is pulled out of a soapy solution and drains from the top.](/Images/godic/202502/11/GenerationSoapFilm2513.jpg")
Soap films are thin layers of liquid (usually water-based) surrounded by air. For example, if two soap bubbles come into contact, they merge and a thin film is created in between. Thus, foams are composed of a network of films connected by Plateau borders. Films are used as model systems for minimal surfaces, which are widely used in mathematics.