Perhaps everyone has observed how a thin crust of ice forms on the surface of the water when it freezes. Broken, it runs on the surface, and it is simply impossible to drown it. And the thing is that solid water is lighter than liquid water.
Archimedes' law
The amazing ability of ice to float and ply on the surface of the water is due to nothing more than the basic physical properties, which are studied in the course of middle and high school. It is known for certain that when heated, substances tend to expand, like, for example, mercury in a thermometer; also, when the temperature drops, water freezes and increases in volume, forming an ice crust on the surface of reservoirs.
An increase in the volume of frozen water often plays a cruel joke with those who forget containers with liquid in the cold. Water literally tears apart the container.
The opinion that microscopic pores filled with air appear in the newly formed ice mass is not erroneous, but it also cannot explain the fact of floating up properly. In accordance with the principles derived and formulated by the ancient Greek scientist, which later received the name Archimedes' law, bodies that are immersed in a liquid are pushed out of it with a force that is equal to the weight characteristics of the liquid displaced by this body.
Physics of water
It is known for certain that ice is about one-tenth lighter than water, which is why giant icebergs are submerged in the ocean by about nine-tenths of their total volume and are visible only for a small fraction. These weight differences are explained by the properties of the crystal lattice, which is known to have no ordered structure in water and is characterized by constant movement and collision of molecules. This explains the higher density of water in comparison with ice, the molecules of which, under the influence of low temperatures, show low mobility and a small energy component and, accordingly, lower density.
It is also known that water has the maximum density and weight at a temperature of 4 ° C, a further decrease leads to an expansion and a decrease in the density index, which explains the properties of ice. That is why in reservoirs heavy four-degree water sinks to the bottom, making it possible for a cooler one to rise and turn into non-sinking ice.
Ice has specific properties, for example, it is resistant to foreign elements, has a low reactivity, differs in the mobility of hydrogen atoms, and therefore has a low yield point.
It is clear that this property is fundamental for the preservation of life on Earth, because if ice had the ability to submerge under the water column, over time, all water bodies of the Earth after a decrease in temperatures could fill with layers that are constantly forming on the ice surface, which would lead to a natural disaster and the complete disappearance of flora and fauna of water bodies from the equator to the opposite poles.
