Why do bubbles take only Spherical Shape?
How fascinating are those beautiful, round, mystical spheres that we blow and chase around! Bubbles – so round! But why haven’t we seen a square, triangle or a rectangular bubble?
The soap film creates a flat plane when you start to blow a bubble on a bubble wand. This flat surface has the smallest surface area but with zero volume of air. When you start blowing air in that soapy film, the liquid soapy skin starts to stretch. This creates a surface tension or tightness in the bubble skin, and it tries to shrink the bubble into a shape with the smallest surface area for the volume of air in it. Thus it takes the shape of a sphere and we have round bubbles.
Exception – When a round bubble is surrounded by other bubbles they stick together to form a different shape and the bubble in the center looks like a cube. If the surrounding bubbles are popped, the one in the center gains back its spherical shape!
thanks Mocomi