What is the phenomenon of subcooling What is the phenomenon of supercooling and the degree of subcoo

Definition of the phenomenon of supercooling:

During crystallization, the actual crystallization temperature is lower than the theoretical crystallization temperature. At a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at that pressure, the phenomenon that the liquid still does not solidify is called supercooled phenomena of liquid. The liquid at this point is called supercooled liquid, which is a thermodynamic condition.

The unstable state will quickly solidify under the action of external friction and make the temperature rise, which is manifested in a V-shaped supercooling curve. The purer the liquid, the more obvious the supercooling phenomenon is. High purity water - 40 degrees Celsius.

It just started to freeze. This is because the liquid is too pure to have the "crystal nucleus" needed for coagulation. When the necessary substances are available, such as putting in a small amount of solids or shaking the liquid, the liquid can solidify quickly.

Principle of the phenomenon of supercooling:

Ice formation is actually a crystallization process in which water molecules of a liquid below their standard melting point are already present in the water with crystal nuclei (ice crystals).

A crystalline structure is formed around the nucleus.

The process of attaching to ice crystals and forming ice can be carried out. But some water is too clean, free of dust and impurities, and the container is very clean and smooth, without such crystal nuclei, ice crystals cannot form because there is nowhere to cling to, so the liquid part of the temperature axis can be extended, even if the temperature is below the freezing point (0°), the water will remain in the liquid state until uniform nucleation crystallization is formed.

In order to carry out the phenomenon of ultra-freezing, the following three conditions must be met:

1. A bottle of water that is very pure, no sediment, no impurities. (Distilled water is preferred.)

2. A smooth container with no scratches on the inside.

3. Store in the refrigerator for a period of time in a refrigerator that can be frozen to minus a few degrees Celsius. (e.g. hours).

What is the phenomenon of supercooling? The foreign guy poured a bottle of water in the desert and it froze instantly!

1. Supercooling:When the crystal solidifies, the solidification temperature should be slightly lower than the solidification temperature, because the solidification temperature is a liquid solid state and the presence of both a solid state is a steady state. The lower the degree of subcooling, the longer the solidification time, allowing the grains to have enough time to grow.

2. Supercooling:If solidification is to take place, a driving force is applied, and this temperature difference slightly below the solidification temperature is the driving force of this solidification process, which is called supercooling. Degree.

So the smaller the degree of supercooling, the larger the grains, and the greater the degree of supercooling, the smaller the grains. However, after the degree of supercooling is large to a certain extent, the atoms do not have time to align and solidify to form quasicrystals and amorphous.

System Instructions. A liquid whose temperature is below the freezing point but still does not solidify or crystallize is called a supercooled liquid. Supercooled liquids are unstable, and as long as a few crystals of the substance are added, crystallization can be induced and the temperature of the supercooled liquid can rise to the freezing point. This unstable state, which changes quickly under a small perturbation, is called metastability.

As the arrangement of molecules or atoms inside a crystal is regular, whereas inside a liquid it is irregular. And the crystallization center contributes to this transformation from disorder to order. The purer the liquid, the more difficult it is for the crystallization center to form. If it is lowered below the freezing point and still not formed, it is subcooled.

In fact, liquid metal always cools below the theoretical crystallization temperature before it begins to crystallize, and the time crystallization temperature is lower than the theoretical crystallization temperature, which is called supercooling. The difference between the theoretical crystallization temperature and the actual crystallization temperature is called supercooling.

<> supercooling phenomenon refers to the phenomenon that the actual crystallization temperature is lower than the theoretical crystallization temperature and hail collapse during crystallization. Under a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at this pressure, and the liquid is still not solidified, it is called the supercooling phenomenon of the liquid, and the liquid at this time is called the supercooling liquid.

Cause: In the process of experiment, if the solution is pure and the cooling rate is fast, it is not easy to produce crystallization centers in the solution, and the phenomenon of supercooling will occur.

The solution is: when the supercooling reaches a certain level, the crystal can be precipitated by quickly stirring and rubbing the pipe wall to produce the crystal center or adding the crystal seed, so as to achieve the purpose of controlling the degree of supercooling.

The <> supercooling phenomenon refers to the phenomenon that the actual crystallization temperature is lower than the theoretical crystallization temperature during crystallization. Under a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at this pressure, and the liquid is still not solidified, the phenomenon is called the supercooling phenomenon of the liquid, and the liquid at this time is called the supercooled liquid.

Cause: In the process of experimentation, if the solution is pure and the cooling rate is fast, it is not easy to produce crystallization centers in the solution, and supercooling will occur.

The solution is: when the supercooling reaches a certain extent, the crystal can be precipitated by quickly stirring and rubbing the pipe wall to produce a crystallization center or adding crystal seeds, so as to achieve the purpose of controlling the degree of overcooling of the jujube balance.

The supercooling phenomenon is a phenomenon in which the actual crystallization temperature is lower than the theoretical crystallization temperature during fast-moving crystallization.

Under a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid under this pressure, and the liquid is still not solidified, it is called the supercooling phenomenon of the liquid. The liquid at this time is called a supercooled liquid, which is a thermodynamic one.

The unstable state will quickly solidify under the action of external friction and so on, and the temperature will rise, which is manifested in a V-shaped shape on the pre-cursor curve of supercooled mu.

In order to carry out the phenomenon of ultra-freezing, the following three conditions must be met:

1. A bottle of water that is very pure, no sediment, no impurities.

2. A smooth container with no scratches on the inside.

3. Put it in the place that can be frozen to Celsius.

Refrigerator at minus degrees for a while.

The phenomenon of supercooling refers to the phenomenon that the actual crystallization temperature is lower than the theoretical crystallization temperature during crystallization. Under a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at this pressure, and the liquid is still not solidified, it is called the supercooling phenomenon of the liquid. This is a thermodynamically unstable state, which will quickly solidify and rise in temperature under the action of external friction, which is manifested in a V-shaped supercooling curve.

The phenomenon of supercooling refers to the phenomenon that the actual crystallization temperature is lower than the theoretical crystallization temperature during crystallization. At a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at this pressure, and the liquid is still not solidified, it is called the supercooling phenomenon of the liquid. This is a thermodynamically unstable state, which will quickly solidify and rise in temperature under the action of external friction, which is manifested in a V-shaped shape on the supercooling curve.

Liquid overcooling. Ice formation is actually a crystallization process, if there is already a crystal nucleus (ice crystal) in the water, the water molecules of the liquid below its standard melting point will form a crystalline structure around the nucleus, attach to the ice crystals, and the process of ice formation can be carried out. But some water is too clean and free of dust and impurities.

The container is very clean and smooth, and without such a crystal nucleus, the ice crystals are so rotten that they cannot form because they have nowhere to cling to, so that the liquid part of the temperature axis can be extended, and even if the temperature is below freezing (0°), the water will remain in a liquid state until uniform nucleation crystallization is formed.

Being able to see this phenomenon illustrates three things:

1. The uniformity of this bottle of water is very good (very pure or homogeneous true solution);

2. In the process of cooling, the cooling is very uniform and not disturbed;

3. The inside of the container is smooth.

Principle: Under a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at this pressure, and the liquid is still not solidified, the phenomenon is called the supercooling phenomenon of the liquid, and the liquid at this time is called the supercooled liquid.

Because the liquid in the bottle is in a "supercooled" state – the liquid temperature is below freezing, but the liquid is not solidified. This is because it requires some force to initiate the process of solidification, allowing a small number of liquid molecules to be neatly arranged into what a crystal looks like, rather than as in a liquid. This process is called nucleation.

This helps some of the liquid molecules to form a crystal-like condensation nucleus in the first place, and other molecules can line up around it. It could be a speck of dust, a rough spot on the surface of the container, or a shock wave when you quickly remove the bottle from the refrigerator.