distributed

throughout the peel

.

In the case of the pomelo, its pores are more compact and compressed near both the top and bottom of the peel, whereas in the middle, they’re larger and more spaced out. In other words, you’ve got two layers of small pores sandwiching a layer of big pores, all within the width of the peel.

If you were to cut open a pomelo and magnify a cross section of its peel, you’d find that it’s populated by countless little holes. (Apologies to readers with trypophobia.) Because these pockets of air keep the substance light and absorbent, the pomelo peel resembles other foam products designed to cushion against impact, like packing peanuts and bubble wrap. But porousness alone is not what makes the peel so protective, according to the mechanical engineering team led by Professor Daniel McAdams. Also important is how that porousness is

This is called gradient porousness, McAdams’s team explains in an article detailing its findings, published in November in the American Society of Mechanical Engineers Journal of Mechanical Design.

While gradient porousness occurs naturally in the pomelo peel, its naturally intelligent design has never been replicated in a human invention. Every man-made foam, from Scrub Daddy sponges to yoga mats, is either uniform or random in their distribution of pores. McAdams’s team was curious about whether this gradient affected a foam product’s impact resistance. So they developed a virtual model of it to find out.

Most engineering design is executed on computers, using software built around complex mathematical computations. Computer modeling allows engineers to simulate products without creating real-life prototypes, which can be prohibitively expensive and time-consuming. For their research, McAdams’s team created a pomelo-inspired simulation of aluminum foam, a common material used in cars to absorb shock in parts of the vehicle that are vulnerable in crashes.

Next, they subjected the simulated foam to impact in two virtual experiments. In one, they applied pressure carefully and continuously. In another, they dropped the foam from a height of five feet. In both cases, the pomelo-inspired foam design absorbed more shock than foam with uniform pore distribution. Nature 1, human ingenuity 0.

This is an important discovery, because it has broad applications in nearly every aspect of human life.