In childhood, many of us heard about this remarkable property of sea shells. We checked how much it is true.

The legend that the sink through the years keeps the noise of the sea, you can find out not only in the yard or on beach. In her art works, they are reported as Russian -speaking (Agnia Barto, Semyon Alts, Andrey Lazarchuk, Igor Garin), and foreign authors (Enid Bliton, Louis Aragon). Inspired by this effect, Nikolai Gumilyov gave the name "Sounding sink" The mug of young poets led by him.

At one time on this question answered Head of the ENT department of the Medical Center, Associate Professor of the ENT Cafedra of the educational and scientific medical center of the President of the Russian Federation Ivan Akulich: “No, not true. If we attach a sink to the ear, we will not hear the noise of the sea, but the sounds surrounding us, which simply resonate against the walls of the shell. The same noise will appear if we attach any other container to the ear, such as a glass or a cup. It's all about sound waves. The noise of the sea has a certain sound frequency. Moreover, this is not just some kind of monotonous sound, but the imposition (interference) of different sounds (hissing, rustling, sound of spray, etc.), which our brain identifies as the noise of the sea. In a closed space (in a shell, a cup, glass), the mass of the sounds surrounding us also superimposed on each other, and we hear a certain rumble, which in its frequency is similar to the frequency of sound waves of sea noise, so it seems to us that we hear the sea surf. In addition, if a person has been to the sea, it is easier for him to draw an analogy with his noise. ”

The physical side of the issue was explained in more detail on the portal Live Science. It turns out that the height of the sound audible in the sound shell depends on its size. It takes more time to reflect the sound in a large sink, so such a sound will seem to us below in a tone than in a small one. Nevertheless, whether it is a high or low sound, in almost all shells it resembles the noise of the surf. In the publication National Geographic It is added that to simulate the “shell effect” you do not even need an extraneous object - it is enough to apply your own palm to your ear.

But the world famous popularizer of science Karl Krushelnitsky refutes a very common thought that can be found in National Geographicand on many other natural science and technical sites. All of them claim that the sound that we hear reflected from the walls is the sound of pulsation (or current) of the blood running inside our ear shells. In confirmation of this conclusion, an example often gives: they say, sometimes we hear this pulsation, putting our heads on a soft pillow.

However, this theory, as Krushelnitsky writes (physicist and physician by education), is easy to refute with a simple experiment. Bring the sink to your ear, listen, then run a few minutes on the beach to increase the blood flow throughout the body, and again apply to the magic sink. You will find that the sound intensity of the "sea surf" remains the same. In general, according to the scientist, the sink next to our ear acts as a sound equivalent of sunglasses. She filters a set of sounds that constantly attack our ears and which we constantly ignore. For example, it misses more sounds of the same frequency, but less - another frequency. After that, the pair of the ear + the brain detects changes in the incoming noise. The brain identifies it as an already familiar noise of the surf and hangs the corresponding “shortcut”.

Is the denial of the role of blood flow in the formation of sound from shells or not is true, but scientists converge in one thing: this effect has nothing to do with the real noise of the surf.