Kundt's Tube

This video is taken from the demo lab of NUS High School. The student there made this Kundt's tube.

Kundt's tube is an experimental acoustical apparatus invented in 1866 by German physicist August Kundt.

That time, it was used to measure speed of sound in gas or solid rod.

Today, we used it to demonstrate standing waves and acoustical force.

To make this tube, we need a transparent horizontal pipe with styrofoam beads inside. Do note, do not use styrofoam beads that are too small as static will cause them to stick to the wall of the tube. I saw online that some put cork duct or talc in it, but I never tried before so not sure whether it works.

Then block one end and attached another end to a loud speaker that is attached to a signal generator to produce a sine wave.

Then you will see like what is appearing in this video.