REEL.IOZ on Instagram: "This is a Rubens’ Tube, an ingenious invention from 1904 that visually demonstrates how sound waves create standing wave patterns. It’s a long metal tube with small holes along its top and connected to a flammable gas source. When the gas is lit, rows of small flames appear. As sound waves are played through one end of the tube, the pressure variations inside cause the flames to rise and fall in sync with the sound’s frequency. The result is a mesmerizing pattern of peaks