In the future, sound insulation materials may be thinner and more effective. British scientists, inspired by the scales of furry moths, want to develop special ultra-thin wallpapers.
The first picture is a silkworm moth named Ji Toumu (Antheraea pernyi) of medium and large moths, with double comb-toothed antennae, pink-brown wings, and beautiful pink eye patterns in the center of the wings. In 2020, the University of Bristol team began to study how these “deaf” moths work. To avoid the pursuit of bats, they found that Ji Tomu silkworm moth can avoid bats through the sound-absorbing scales on its body.
The foraging method of bats adopts echolocation. In addition to using vision, it also emits ultrasonic waves. The sound waves are reflected back to the bat’s ears when they hit objects. Some moths can hear the sound waves and avoid them, but some moths can’t actually hear them and need another “Skill”.
The team found that these moths have evolved special scales on their wings and chests that can absorb up to 85% of incoming sound. The echolocation of bats is almost useless, so the scientific team wanted to explore whether it could be applied to sound insulation materials.
The team first cut 8-centimeter circles from the wings of dead moths, put them into aluminum disks of the same size, and then used a horn to send ultrasonic signals to the disks. Tissue can absorb up to 87% of sound energy, and they were surprised that the moth’s wings are so thin and the scales are only one-fifth the thickness of the sound wavelength.
The team believes that although the study tested ultrasound waves that the human ear cannot hear at all, the artificial version of the scales should be used in sound insulation materials. Chief scientist Marc Holeried said that the moth scales will inspire the next generation of sound-absorbing materials. Maybe one day we can use Ultra-thin sound-absorbing wallpaper, which combines sound insulation and beauty, and also replicates the trick that allows moths to be perfectly invisible.
(Image credit: University of Bristol)
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