Why is honeycomb hexagonal?

The perfect hexagonal shape of honeycomb cells — once thought to be an incredible feat of math-savvy insects has now been explained by simple mechanics.  Scientists have marveled at the angular perfection of honeycomb for centuries, but none have been able to clearly describe how it forms. Engineers in the U.K. and China have taken a step forward by showing that the cells actually start off as circles — molded by the shape of a bee's body and then flow into a hexagonal pattern seconds later.

Using a honeycomb grown at a research facility in Beijing, the researchers were able to carefully ward off the bees and photograph the bare honeycomb seconds after formation, providing the first clear evidence that cells naturally start as circles. They then observed honeybees heating the wax after the initial cell formation — a phenomenon identified in previous studies, but never analyzed in close detail — and found this to be the key step in hexagon-formation.  By heating the cells, the bees cause the wax to become molten and flow like lava. Once the wax starts flowing, the cell walls naturally fall flat and take on the shape of a hexagon, like adjoining bubbles in a bath. This is physically the simplest and most stable way for cylinders to merge, Karihaloo said.

Honeycomb cells start off as circles within the first few seconds of formation (a) and then eventually morph into hexagons (b).
(Photo: B.L. Karihaloo, K. Zhang and J. Wang)  

Post text excerpted from Mother Nature Network, Copyright 2013 LiveScience, a TechMediaNetwork company.