Scientists and engineers have teamed up to develop a new kind of window that can go from transparent to opaque with a flick of a switch. The material is less than a quarter-inch thick, but is composed of two layers of transparent silicon with a layer of liquid between them. Most of the time, the liquid is oil, but when the sun beats down, colored water is introduced to make the window pane opaque, reducing the sun's heat absorbed into the room. The technique was inspired by krill, a tiny crustacean that can change its own body from transparent to opaque for defensive purposes. This new kind of window pane should be 30% more efficient than using blinds, according to computer models, which translates into a huge saving on air conditioning costs. So far, it has only been made in the size of a regular window pane. If it can be scaled up, this material might be suited to covering existing windows, or being the entire window in new construction, or could even be used as an entire building facade. <a href="https://www.fastcompany.com/90775123/these-color-changing-energy-saving-windows-are-inspired-by-an-unlikely-sea-creature">Read how it works at Fast Company.&nbsp;</a>​ (Image credit: <a href="https://commons.wikimedia.org/wiki/File:Meganyctiphanes_norvegica2.jpg" alt="Øystein Paulsen" class="on">Øystein Paulsen</a>)&nbsp; #window #windowshade #energyefficiency