Agonal breathing of the dying. John Cheyne described it in 1818, and William Stokes in 1854.

This name became very popular in the USSR after March 4, 1953, when the first official medical bulletin on Stalin’s condition was published.

And Esprit de L’Escalier recently discovered this “breath” in an ordinary kettle (LITERALLY, not ironically figuratively) filled with cooling boiling water!

Description of the process:

I put a kettle of cold water on an electric heating coil and after about seven minutes it boils. The kettle is whistling, steam under low pressure passes through a hole in the lid of the spout and due to this, vibrations of the jet and air occur and a whistle is heard. Usually, I take it off the heated spiral and the whistling stops immediately.

But the other day I decided to leave it, turning off the current in the spiral, and let it “calm down” on its own. At first, the whistling continued, the spiral, “clad” with a layer of steel shell, cooled slowly. Then the whistling began to be heard periodically, as if in short pulses. And so it went on for quite a long time, and the periods of “silence” lengthened, the whistles shortened and weakened in amplitude.

That is, it was clear that the boiling in the water had gone from continuous to pulsed, something like sudden “explosions” with intense vaporization.

Moreover, if the kettle was placed on a cold surface, the whistling stopped immediately. This means that the cooling massive spiral continued to supply the water with thermal energy.

But why did the process become explosive, impulsive, and not gradually subside? After all, the heat has already stopped being released from the spiral and it began to cool down gradually. This means that the water, too, should have gradually cooled down and the boiling stopped smoothly.

And suddenly there are such rather long “explosions” of steam at intervals?

An attempt at explanation:

There is a condition called “superheated liquid” or “supercooled.” The fact is that vaporization in water occurs on the so-called “nuclei”, as well as freezing. That is, the water contains certain impurities, usually microbubbles of air dissolved in it, which become the centers of vaporization during boiling. So, if you “degass” water, that is, remove these nuclei-centers of vaporization from it, then the water will not boil calmly and evenly, but at a temperature ABOVE the boiling point, it will “explode” in an instant.. Because there are practically no centers, and any accidental phenomenon that causes the appearance of such a center immediately causes an explosive boiling of the entire volume of water.

“Explosion”!

The same thing happens with supercooled water, when the water is not frozen at a temperature below zero, but it is worth throwing some grain into it, and all the water will instantly turn into ice.

What was going on in the kettle? Due to the relatively long boiling time, the remaining water was degassed and the number of vaporization centers decreased sharply, but evaporation from the surface continued, thereby preventing air from dissolving in it and considering, in addition, that air dissolves in cold water better than in hot water. Therefore, the water at a still high temperature did not “find” the centers of vaporization and did not boil constantly. But when some center appeared by chance, it immediately locally exploded and near this center.

A short whistle sounded.

The same explanation applies, I believe, to another case, described by me in the article “Exploding water”. The water boiled there not because of the heating, but because of the decrease in atmospheric pressure at room temperature. But it also boiled up with an explosion.

Why?

When I just put a cup of water in the vacuum chamber and the pump started pumping air out of the chamber, the pressure dropped and at room temperature it became lower than the pressure of saturated water vapor at this temperature. The water was boiling peacefully. But when I poured a thin layer of oil on a layer of water, then the water boiled with an explosion.

Why?

I think it’s a process similar to a kettle. When the air was pumped out, the water was completely degassed through the oil layer. But it also prevented the reverse process, PREVENTING the external, though very discharged, air from dissolving into the surface layer of water and thereby creating vaporization centers. Water at a very low pressure became “superheated” at room temperature and boiled explosively!

I think this explanation interprets the process of “water explosion” in a vacuum chamber more correctly than the one given in the “Exploding water” note!

Faciant meliora potentes.

If I’m wrong, let my seniors correct me.

6 I 2026