Technologies Inspired by Nature
Originally published on Cosmos Magazine
After 3.5 billion years of evolution, nature has come up with some ingenious solutions for everything, from defying gravity with stickiness to staying cool in the heat. Cathal O’Connell explains.
HIVE MIND GRID
Though nobody ever tells them what to do, bees in a hive instinctively sense what jobs need doing and get on to it – based simply on where in the hive they are and what other bees are doing around them. Regen Energy in the US adapted this ‘swarm logic’ to improve the efficiency of energy grids. Instead of using a central system to redirect power loads, the company places local controllers that communicate wirelessly with one another, and figure out on their own where power needs to go.
In 1941, Swiss electrical engineer George de Mestral went hunting in the Alps and afterwards noticed his clothes, and his dog’s fur, were covered in burdock burrs. This mechanism of clinging to passing creatures is the burdock’s way of spreading seeds across greater distances. Mestral put one of the burrs under a microscope and discovered the simple hooks which allowed it to cling to loops in his socks and in dog hair. The discovery inspired Mestral to create velcro, which he patented in 1955.
The secret to a gecko’s gravity-defying grip turns out to be the rows of tiny hairs, called setae, on its toes. The hairs cling to any surface using the sticky van der Waals force, which only works at microscopic scales. The advantage is a reversible, strong grip without the need to deposit an adhesive. In recent years engineers have managed to reproduce similar setae from silicone, leading to myriad variations of gecko-skin technology. Among them are a gizmo to allow humans to climb a sheer glass wall, robots able to pull objects hundreds of times their own weight, and grippers for space repairs.
WHALE FIN WIND-TURBINE
In a Boston gift shop, Frank Fish, a biologist, noticed the bumps running along the fins on a statue of a humpback whale, and assumed the artist had made a mistake. Instead of protruding from the back edge of the fins, the bumps surely ran along the front. But the artist was right. A row of warty ridges creates tiny vortices which help the fin cut through the water, and explains the humpback’s surprising agility. After studying this ‘tubercle effect’, Fish discovered that adding rows of bumps to turbine blades reduced drag and noise, and increased their efficiency.
Inspired by the microscopic scales on shark skin, NASA scientists developed a drag-reducing coating for ships. The technology helped the Stars and Stripes win the Americas’ Cup sailing race in 1987. The coating was so successful, the competition deemed it an unfair advantage and banned the technology before later reinstating it.
BULLET TRAIN KINGFISHER
A high-speed train emerging from a tunnel generates a tremendous thunderclap due to the air pressure that builds up in front of the nose. In the 1990s Japanese engineer Eiji Nakatsu noticed that kingfishers could dive into the water with barely a splash. His design for the Shinkansen bullet train, based on the kingfisher beak, not only reduced the noise of the train but was also more aerodynamic, using less power and enabling higher speeds.
African termites have evolved some clever designs to keep their mounds at a nearly constant temperature, in environments that swing from 40 °C in the day to less than 2°C at night. Termites construct their mounds with a passive cooling system, using a series of vents along the top and sides. Architect Mick Pearce used a similar strategy when he designed the Eastgate centre, an office complex in Harare, Zimbabwe. Warm air exits through chimneys at the top of the building, while cooler air is drawn up from underground.