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Why are bubbles round?

Baloon and bubble
Bubbles and balloons have a lot in common!  Scientists refer to them as  "minimal surface structures."  This means that they always hold the gas or liquid inside of them with the least possible surface area.  The geometric form with the least surface area for any given volume is always a sphere, not a pyramid or a cube or any other form.
Bubble Animation
Table Of Contents
An amazing exception to the rule!  (Not really.) When a normally round bubble is surrounded by other bubbles, it can be made to take on a seemingly odd shape.  Here, a bubble filled with smoke to make it more visable, is surrounded by six other bubbles, it appears to be a bubble cube!  If the surrounding bubbles are popped, though, the bubble in the center reverts to its natural "round" shape.
Bubble cube