20. BUBBLE – PERFECT SPHERE

What can we say about a sphere? It has incredible symmetry: it remains unchanged under any rotation about its centre, under any rotation about a line throught its centre, and under any reflection in a plane through its centre. It has the largest volume amongst all solids with a given surface area. It has the same width in every direction. An object of great beauty!

And is the bubble a perfect sphere? Well, probably not, with gravity causing some small distortion. But close!

http://en.wikipedia.org/wiki/Soap_bubble

http://en.wikipedia.org/wiki/Sphere