Introduction Fig 1. Kalle watching soap bubbles. Buildings have light-weight roofs in the shape of soap films. Video ( 8.6MB, 2.3MB) A magical fascination arises from seeing colorful soap bubbles flying in the wind. The observer is immediately attracted while watching the beautiful creations and he can imagine touching them with a satisfying childlike curiosity. Yet behind these aesthetically pleasing shapes lie deep mathematical problems, as well as practical applications in architecture, physics and chemistry - which one can understand and appreciate, in spite of their complexity, via the amusing story that unfolds in this video. Young Boy Kalle. The shape of a round bubble is only the simplest example of an incredible wealth of shapes that arise with soap films. Imagine a simple experiment with soap films in the kitchen:

dip a curved metal wire into a mixture of water and dish-washing detergent, and, when you cautiously pull it out, a soap films forms. With amazing elegance and simplicity, this soap film solves a historic mathematical problem, namely, the soap film finds the least surface area amongst all imaginable surfaces spanned by the wire. Therefore, mathematicians call them "minimal surfaces" since they minimize area.