I’m Ken Kuwako, your Science Trainer. Every day is an experiment!<\/b><\/p>\n
Imagine the hustle and bustle of the city or the deafening roar of a jet engine vanishing in an instant, leaving you in a world of pure silence where only your music remains. Are you using “Noise-Canceling” technology? While it’s now a standard feature in our smartphones and earbuds, there is actually an amazing application of wave physics hidden behind the scenes. Today, I want to share a unique way to let an entire classroom witness this invisible power to silence sound!<\/p>\n
At its core, “sound” is simply a vibration of air that travels as a wave. In a nutshell, noise-canceling technology works by using sound to cancel out sound.<\/p>\n
A microphone picks up the surrounding ambient noise, and the system instantaneously creates an identical wave but in reverse (this is called an inverted phase). When these two waves collide, the peaks of one meet the valleys of the other, flattening the wave and causing the sound to disappear. In physics, we call this the Principle of Superposition. Here is what it looks like when demonstrated with a spring:<\/p>\n