The 'Perfect Fire' Exists, and Here's What it Looks Like

From campfires first built 35,000 years ago by our human ancestors to bonfires on the beach for roasting s'mores, people have been building fires relatively the same way for thousands of years. Humanity has known for some time what constitutes the "perfect fire," and now researchers are letting us in on the secret.

In a new study published in the journal Nature Scientific Reports, a team from Duke University shows that, all other variables being equal, the best fires are roughly as tall as they are wide.

"Humans from all eras have been relying on this design," Adrian Bejan, a professor of mechanical engineering at Duke University, said in a statement. "The reason is that this shape is the most efficient for air and heat flow. Our success in building fires in turn made it possible for humans to migrate and spread across the globe."

This finding falls in line with Bejan's previous work in Constructal Law, which postulates that all living systems, such as trees, rivers or air currents, are "flow" systems that evolve to provide easier flow access. Now internationally recognized, the law is increasingly finding applications in improving design and maximizing efficiency of man-made systems.

But it seems that since the dawn of time, humans have applied the idea of Constructal Law to building fires, using the same general shape every time. And now we know the reasoning behind why the triangle-shaped blueprint has lasted us until today.

"Our bonfires are shaped as cones and pyramids, as tall as they are wide at the base. They look the same in all sizes, from the firewood in the chimney, to the tree logs and wooden benches in the center of the university campus after the big game. They look the same as the pile of charcoal we make to grill meat," Bejan said. "And now we know why."

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