Kundt’s tube is a popular experiment commonly used in schools, in which standing sound waves are made visible inside a glass tube. A fine powder is stirred up in areas of high sound particle velocities, so that one can measure the wavelength of the sound waves by examining the patterns created. In this way, the ‘invisible’ can be made visible.

However, when looking at educational contexts, Kundt’s tube is an experiment with several shortcomings—despite its popularity and prevalence: The glass tube is big, expensive and fragile. Additionally, during the experiment itself, the sound tends to be quite loud due to the high sound pressure needed so that communicating during the experiment becomes hard or even impossible.

In this article, we propose a silent and low-cost alternative to commonly used setups which can easily be constructed by using 3D-printed parts as well as readily available ultrasonic transmitters. This makes Kundt’s tube even implementable as an experiment done by students themselves.

Kundt的电子管是学校中常用的一种流行实验，在玻璃管中可以看到声波。细粉会在高声粒子速度的区域被搅动，因此人们可以通过检查产生的模式来测量声波的波长。这样，可以使“不可见”可见。

但是，从教育背景来看，Kundt的试管是一个实验，它有几个缺点-尽管它很流行且很流行：玻璃试管大，贵，易碎。另外，在实验本身期间，由于所需的高声压，声音往往会很大声，因此在实验过程中的交流变得困难甚至无法进行。

在本文中，我们提出了一种无声且低成本的替代方法，以替代常用的设置，可以通过使用3D打印的零件以及易于使用的超声波发射器轻松构建该设置。这使得Kundt的试管甚至可以作为学生自己进行的实验来实施。