The Singing Tea Strainer
If a jet of water hits the perforated structure of a stainless steel sieve, a whistling sound can sometimes be heard. It occurs when water vortices periodically react on the sheet metal and stimulate resonance vibrations.
In the past, the preparation of tea was started by a whistle, today it is more likely to end with it. In any case, the kettle for the stovetop with its shrill whistle is now almost obsolete, while tea strainers made of stainless steel are becoming more and more common. They cause a strange acoustic phenomenon: numerous videos on the Internet show how the utensils make sounds when cleaning in the sink.
The chance discovery is easily reproducible after a short trial and under the right circumstances, different makes reveal their musicality. On the one hand, the water jet has to hit the metal at a certain speed. This increases with the drop height. With some strainers, the distance between the tap and the sink is not sufficient, and the trick can only be achieved in the bathroom or with the garden hose. On the other hand, the perforated surface only sounds when hit at a certain angle. In order to find the optimal area for whistling, it is advisable to raise and lower the sieve a little under the water jet, varying the inclination. It works best when the beam hits the flat ground. In a series of experiments, my colleague Wilfried Suhr and I were even able to get a screen on the shell side toning…