Although simple chemical formula, the water - a substance with very unusual properties.It carries a lot of mysteries that are sometimes beyond the power of even the scientists unravel.Here are five of the most interesting facts about water:
1. Hot water freezes faster than cold
Take two water containers: one pour hot, and in another - cold water and place them in the freezer.Hot water freezes faster than cold, even though, logically, the first was to turn into ice cold water: hot water because it is necessary to first cool to cold, and then turns to ice, while the cold water to cool off is not necessary.Why is this happening?In 1963, a Tanzanian student named Erasto B. Mpemba (Erasto B. Mpemba) freezing prepared ice cream mix, noticed that the hot mixture in the freezer freezes faster than cold.When the young man shared his discovery with the physics teacher, he just laughed at him.Fortunately, the student proved persistent and persuaded a teacher to conduct an experiment, which confirmed his discovery under certain conditions hot water freezes faster than cold indeed.
Now this phenomenon of hot water freezing faster than cold is called "Mpemba effect."However, long before it is a unique property of water, it was noted by Aristotle, Francis Bacon and René Descartes.
Scientists have until the end and did not understand the nature of this phenomenon, explaining the difference in his or colds, evaporation, ice formation, convection, or the influence of diluted gases at the hot and cold water.
2. supercooled and "instant" freezing
Everyone knows that water always turns to ice when cooled to 0 ° C ... except in some cases!Such a case, for example, is supercooled, which is a property of very pure water to remain liquid even when cooled to a temperature below the freezing point.This phenomenon is possible because that the environment does not contain any crystallization centers or nuclei which might cause the formation of ice crystals.And so the water remains in liquid form even when cooled to a temperature below zero degrees Celsius.
crystallization process can be triggered, for example, gas bubbles, impurities (pollution), uneven surface of the container.Without them, the water will remain in the liquid state.When the crystallization process starts, you can see how supercooled water instantly turns to ice.
Note that the "superheated" water also remains liquid even when heated to a temperature above the boiling point.
3. «Glass" water
Do not hesitate to call, how many different states have water?If you answered three: solid, liquid, gaseous, then you are mistaken.Scientists have isolated at least five different states of water in liquid form and 14 states in the frozen form.
remember a conversation about a supercooled water?So, no matter what you do, at a temperature of -38 ° C even the purest supercooled water suddenly turns into ice.What will happen when the temperature decreases further?At -120 ° C water starts to happen something strange: it becomes extra-viscous or viscous as molasses, and at temperatures below -135 ° C it turns into a "glass" or "glassy" water - solid, in which no crystalstructure.
4. Quantum properties of water
At the molecular level, water is even more surprising.In 1995, scientists conducted experiments on neutron scattering gave an unexpected result: physicists found that the neutrons are aimed at water molecules, "see" 25% fewer hydrogen protons than expected.It turned out that at a speed of one attoseconds (10 -18 seconds) there is an unusual quantum effect and the chemical formula for water instead of H2O, it becomes H1.5O!
5. Do you have the memory of water?
Alternative official medicine homeopathy states that a dilute solution of the drug may have a therapeutic effect on the body, even if the dilution factor is so great that the solution is not left with nothing but water molecules.Proponents of homeopathy explain this paradox concept called "water memory", according to which the water at the molecular level has a "memory" of a substance, once dissolved in it and retains the properties of the initial concentration of the solution after there are no longer any molecule ingredient.
international team of scientists led by Professor Madeleine Ennis (Madeleine Ennis) from Queen's University Belfast (Queen's University of Belfast), criticized the principles of homeopathy, in 2002 conducted an experiment to disprove once and for all the concept.The result was reversed.After that, the scientists said they were able to prove the reality of the effect of "memory of water".However, experiments carried out under the supervision of independent experts, have not yielded results.The debate about the existence of the phenomenon of "memory of water" are continuing.
on materials 5 Really Weird Things About Water
Articles Source: mainfun.ru
