It's a warm summer night in the city, but instead of sleeping with the windows open to let a breeze in, you've got them all closed to keep your bedroom quiet. It's a 'lesser of two evils' decision that people living in crowded urban centers might soon not have to make. Researchers in South Korea have developed a remarkable new type of window that dampens sound while still allowing air to pass right on through.
Developed by Seong-Hyun Lee at the Korea Institute of Machinery and Materials and Sang-Hoon Kima at the South Korea Mokpo National Maritime University, the nitty-gritty of how the window works is detailed here. But in layman's terms, the windows are made up of two plates of transparent acrylic sitting 40mm apart that work as a resonance chamber, diminishing the energy of sound waves passing through. And to maximise the window's efficiency, it's perforated with 50mm holes that allow more sound to enter and get trapped, without obstructing breezes.
The exact science of how the windows work is of course far more elaborate and worth a read if you've got a few moments, but in testing it's been found to reduce sounds by an impressive 20 to 30 decibels—enough to turn a traffic-filled street into a sleep-friendly murmur—across various frequency ranges depending on the size of the perforations.