If you get into a predicament in outer space, yelling won’t get you very far, because sound waves need a medium to travel through. Here on Earth, that’s usually air, although we can also hear quite well underwater.
But wouldn’t it be cool to hear what vacuum actually “sounds” like? This idea struck science student and YouTuber Cody Reeder after a recent acquisition of a new vacuum chamber - an enclosed container from which air and other gases are sucked out with the use of a special vacuum pump, creating a low pressure environment inside.
There are a great many things you can do with a vacuum chamber, such as testing scientific instruments that will need to operate in outer space, or removing air bubbles from liquid plastics before they’re moulded, a process called ‘vacuum degassing'.
Or - why not stick a camera in there and simply record the air going out, thus creating a perfect demonstration of how sound waves travel with the help of the air around us. That’s exactly what the latest video on Cody’sLab is about.
The video is just a quick impromptu demonstration, but the effect vacuum has on sound is really impressive. The camera is placed inside the chamber, but even once Cody closes and seals it, you can hear him talking through the glass - as he keeps talking and the air is removed from the chamber, you’ll notice a huge difference. (If you’re wearing headphones, do watch out for the loud moment when he starts letting the air back in!)
In the traditional sense of what we refer to as ‘sound’, the vacuum of a chamber is a great approximation of the lack of sound one would experience in outer space where the vacuum is far more pronounced, with only rogue hydrogen atoms here and there floating through the nothingness between celestial objects and interstellar clouds.