Go ahead and order this battery pack, as the noise-canceling wallpaper may not be too far away.
Scientists have found that when they mount small sections of moth wings on a hard surface, they are able to absorb up to 87% of incoming sound waves.
The University of Bristol’s research team initially discovered that single scales on moth wings absorb the echolocation calls used by bats.
Absorbing sounds are all too high to be heard by humans, so more work is needed to reduce the range of absorption that will be used in practice.
But in the future, we may be able to mimic this wing-canceling wing texture on the outside of buildings to absorb traffic noise or reduce aircraft weight.
Professor Marc Holderied of the School of Biological Sciences said: “Moths will inspire the next generation of sound-absorbing materials.
“New research has shown that one day it will be possible to decorate the walls of your home with ultra-thin sound-absorbing paper, using a design that copies the mechanisms that stealthy acoustic camouflage offers to moths.”
An image close up of a moth wing showing a ladder on the surface. These absorb the echolocation calls that bats use to find prey and effectively hide them from their predator.
A close-up image of a ladder lying on the wing of a moth, showing its unique ribbed structure
Moths are under great predation pressure from bats and have developed a large number of defenses in their survival effort, including their unique structure that absorbs echolocation calls.
ECOLOCATION AND ARTENES
Bats hunt at night by echolocation, where they use sound waves and echoes to determine the location of their prey.
Moths are under a lot of predation pressure from bats and have developed a lot of defenses in their effort to survive.
Scientists at the University of Bristol discovered in 2020 that moth wing scales act as sound absorbers, making them almost invisible to their nocturnal predator.
Male hawks are also known to rub their genitals against their abdomen to emit a sharp ultrasonic squeak that scares away some bats.
An elephant hawk
Bats developed the ability to “see” in the dark by echolocation about 65 million years ago.
Echolocation is when an animal emits a sound that is reflected in nearby objects, allowing it to create an image of its surroundings in low light and find food.
Moths are under a lot of predation pressure from bats and have developed a lot of defenses in their effort to survive.
British scientists discovered in 2020 that moth wing scales act as sound absorbers, making them almost invisible to their nocturnal predator.
They proceeded to study whether the wing structure could be used in sound-absorbing panels when not moving in free space.
Professor Holderied said: “What we needed to know first was the performance of these moth scales if they were facing an acoustically highly reflective surface, such as a wall.
“We also needed to find out how absorption mechanisms could change when scales interact with this surface.”
Scientists attached small sections of the moth wings to an aluminum disk before systematically testing their absorption capacity.
Sections of the wing were tested with and without the attached flakes, both on the surface of the upper and lower wing.
They observed how sound absorption was affected by the orientation of the wing relative to the incoming sound and the number of layers of wing scale used.
It was revealed today in Proceedings of the Royal Society A magazine that the wings absorbed up to 87% of incoming sound energy, even when mounted on a sound-absorbing substrate.
The noise cancellation effect is also broadband and omnidirectional, covering a wide range of frequencies and angles of sound.
The lead author, Dr. Thomas Neil, said: “What’s even more impressive is that the wings do this even though they’re incredibly thin, with the scale layer only 1/50 the thickness of the length of sound wave they are absorbing.
“This extraordinary performance qualifies the moth wing as a natural acoustic absorbing metasurface, a material that has unique properties and capabilities that cannot be created with conventional materials.”
a: Location of wing samples taken from the moth species Antheraea pernyi for testing. b: Experimental configuration to characterize the angular distribution of the sound reflection of wing and metal disk samples. c: The wing sections were tested with (intact) and without (bald) the attached scales, both on the surface of the upper wing (dorsal) and on the lower wing (ventral).
Graph showing the reflection coefficient of different surfaces when exposed to sounds of different frequencies. The higher the reflection coefficient, the less sound the surface absorbs. Left: upper surface of the wing scale (dorsal) Right: lower surface of the wing scale (ventral)
The research opens the door to use the texture of the wing to create ultra-thin sound-absorbing panels that could be mounted on the outside of buildings.
Noise pollution is the second leading cause of health problems, right after the impact of air quality.
It is related to hearing loss, high blood pressure, heart disease, sleep disorders and stress.
As cities grow stronger with the growth of the world’s population, there is a growing need for efficient, non-intrusive soundproofing solutions.
In addition, they could be used in noisy modes of transportation such as cars and aircraft cabins to reduce their weight and therefore fuel consumption and carbon emissions.
Subsequent research by Bristol scientists will involve prototyping materials with a texture based on the sound absorption mechanisms of the moth.
The absorption they have characterized in the scales of moth wings is all in the range of ultrasonic frequencies and above that which humans can hear, the lowest is 20 kHz.
The next challenge is to design a structure that works at lower frequencies while retaining the same ultra-fine architecture that the moth uses.
How moths use their furs to make them undetectable to bats
You might think that layers of invisibility are science fiction and Harry Potter stuff, but it seems like the realm of insects is really something.
Scientists have discovered that moths can become almost invisible to bats thanks to their furry ones
Tests found that 85% of the sound signals (high-pitched crickets) used by bats to locate their prey were absorbed by moth hairs.
This reduced by almost 25% the distance a bat could detect a moth, increasing its chances of survival.
Moth hairs are actually “hair-like” scales and look structurally similar to the fibers used in soundproofing technology, said research led by the University of Bristol.
Read more here
British scientists discovered in 2020 that moth wing scales act as sound absorbers, making them effectively invisible to their nocturnal predator.