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J. Perelman
"Entertaining physics". Book 2.
Chapter 6. Properties of liquids and gases

THE SEA, WHICH CANNOT DROWN

This sea exists in the country known to mankind since ancient times. This is the famous Dead sea of Palestine. Its waters are extremely salty, so that they can not live any living creature. Sultry, without rain, the climate of Palestine is a strong evaporation of water from the sea surface. But only pure water evaporates, dissolved as salts remain in the sea and increase the salinity of the water that's why the Dead sea water contains not 2 or 3% salt (by weight), as most of the seas and oceans, and 27 percent or more; with the depth of the salinity increases. Now, the fourth part of the content of the Dead sea are salt dissolved in the water. The total amount of salts in it is estimated at 40 million tons.

The high salinity of the Dead sea makes one feature: the water of this sea is considerably heavier than ordinary sea water. To drown in such a heavy liquid cannot: the human body is the easier it is.

The weight of our body is noticeably smaller than the weight of an equal volume of dense salty water and, therefore, the law of navigation, unable to live in the Dead sea to drown; he POPs up in it like floats in salt water egg (which in freshwater drowning)

Humorist mark TWAIN, who visited this lake-sea, comic thoroughness described the extraordinary feeling that he and his companions experienced swimming in the heavy waters of the Dead sea:

"It was fun bathing! We could not drown. Here you can stretch out on the water at full length, lying on his back with his hands folded on his chest, and a large part of the body will remain above water. You can just raise your head... You can lie very comfortably on the back, lifting the colony to the chin and covering their hands, but soon will turn over as head outweighs. You can stand on your head - and mid chest to the end of the feet will remain out of the water, you will not be able to keep this position. You can't swim on my back, advancing much to go significantly as your feet sticking out of the water and you have to start with only heels. If you float face down, then ludigames not forward and back. The horse is so unstable that can neither swim nor to stand in the Dead sea, and she immediately falls on the side"

In the picture you see a man, quite conveniently located on the surface of the Dead sea; a large proportion of the water allows it in this position to read the book to protect the umbrella from the burning rays of the sun.


People on the surface of the Dead sea (with pictures).

The same extraordinary qualities of the water of the Kara-Bogaz-Gol (Bay of the Caspian sea* and not less salty water of the lake Elton, containing 27% of salts.

Something you have to experience those patients who take salt baths. If the salinity is very high, as, for example, in the old Russian mineral water, the patient has to exert a lot of effort to stay on the bottom of the bath. I heard a woman treated in Staraya Russa, indignantly complained that water was positively pushed her out of the bath". It seems that she was inclined to blame not the law of Archimedes, and the resort...

The degree of salinity of water in different seas several varies, and accordingly the court sitting is not equally deep in sea water. Maybe some of you have happened to see on Board a ship near the waterline so-called "mark Lloyd" - a sign showing the maximum water-lines in the water of different density. For example, below the cargo brand means a maximum waterline:

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Truck brand on Board the ship. Designation marks are made at the level of the waterline. For clarity they are shown separately in the enlarged view. The letters are explained in the text.

 

in fresh water (Fresch Water) .............................. FW
in the Indian ocean (India Summer) IS .......................
in salt water in summer (Summer) .......................... S
in salt water in winter (Winter) ............................ W
in the Planting. Atlant. the ocean in winter (Winter North Atlantik) .. WNA

We have these brand introduced as a compulsory since 1909

Note in conclusion that there is a kind of water, which in its pure form, without any impurities, notably heavier than ordinary; its specific gravity of 1.1, i.e. 10% more than normal; therefore, in the pool with this water man, not even able to swim, hardly could drown. This water is called "hard" water; its chemical formula D2O (included in its composition hydrogen consists of atoms, which is twice heavier atoms of ordinary hydrogen, and is designated by the letter D). "Hard" water in small amounts dissolved in common: in a bucket of drinking water contains about 8,

Heavy water composition D2O (types of heavy water of different composition may seventeen) now produces almost pure form; the admixture of ordinary water is about 0.05%.**

* The specific weight of water of the Kara Bogaz-Gol - 1,18. "In this dense water you can swim without the use of effort and not skirting the law of Archimedes, to drown impossible", says concerning this researcher (A. D. Pelsh, Karabogaz, 1934).
** Heavy water is widely used in nuclear technology, in particular, in nuclear reactors. It is extracted from regular soda industrially in large quantities. (Approx. as amended).

Entertaining physics J. Perelman

 




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