Don’t blink, a miracle will happen immediately! A bottle of mineral water just rushes to the table, and it starts to freeze from top to bottom.
Now change your position, place the mineral water bottle on the table, and use your finger to flick the bottom of the bottle. This time the ice freezes quickly from the bottom of the bottle to the top.
Not only that, there has been reports on TV that after the soldiers stationed in the Qinghai-Tibet Plateau of my country opened the cap of a bottle of mineral water, the water immediately freezes from top to bottom.
Some people suspect that this is a magic show, while others say that it must be that special medicines are added to the water, but in fact, there is nothing. What's going on?
Magical supercooled pure water
We all know that when the water temperature drops to 0℃, it will freeze, but some water can persist to minus 48.3℃ under normal pressure before freezing. Not only does this water not add any antifreeze agent, it is even pure and cannot be pure. Just like the bottled water just now, it is not ordinary water, but super-cooled pure water, that is, pure water with a temperature below 0℃.
Magical Icing Method
In addition to applying external force to supercooled pure water to freeze, there are other ways. For example, put a piece of ice in a cup and then slowly pour super-cooled pure water on the ice, we will find new ice slowly growing and piled up on ice cubes .
Think about it, if the ice cube is thrown into too cold pure water, will it still freeze? We need to observe patiently and carefully, and you will find that the water in the cup will slowly freeze. But the test effect is not very obvious.
Let’s do another more intuitive experiment. When we place the ice cubes on the surface of super-cooled pure water, we will find that the water surface is slowly freezing, and it only takes a short period of time that the ice cubes can be completely frozen without sinking.
In order to clearly review this process, we will do another experiment and put a small ice cube in supercooled pure water. It was found that the ice cubes lightly placed on the left will freeze slowly in a radial shape from the water surface, while the ice cubes completely immersed in the water will freeze quickly near the ice cubes.
magical condensed nucleus
After reading the above magical icing phenomena, everyone should have discovered the secret to freezing of super-cold pure water - exert external force or add "medicine leads" that is, the ice core.
In fact, two key conditions must be met to make the water freeze, one is sufficiently low temperature and the other is condensation nucleus. The ice nucleus is a homogeneous condensation nucleus, while applying external force makes the inner wall of the bottle a coagulant nucleus, which is a heterogeneous condensation nucleus. Then the question is: If you add cold small gravel to the super-cold pure water, can it promote icing? Please write your answer in the discussion area.
What is the use of cold water?
has studied cold water and freezing, such as how to ensure that fruits and vegetables are below freezing point and not freezing during transportation, so that they do not change the color of the food nor the quality; the body fluid freezing point of polar bone fish is minus 0.6℃, but it can survive at minus 1.9℃, which provides ideas for studying the resurrection of living living bodies.
