This kind of fork-shaped tube was used to study the motions of different parts of a vibrating Chladni plate. If the ends of the tube were held over two zones that were vibrating in the same direction, a sound would be heard, but if the vibrations were in opposite directions they would cancel each other out (interfere) and the sound would be greatly reduced.
Source: Steven Turner; Curator, Physical Sciences, National Museum of American History, Smithsonian Institution.
Corporation, Zenith. 1971. “Track From The “Getting Through“ Album By The Zenith Radio Corporation”. https://www.youtube.com/watch?v=9vqY7cJpwRs&t=16s.
Corporation, Zenith. 1971. “Track From The “Getting Through“ Album By The Zenith Radio Corporation”. https://www.youtube.com/watch?v=9vqY7cJpwRs&t=16s.
