How are bubbles created when water boils? Please tell me

Before boiling, the bubbles produced by the water are large to small. The bubbles move from the bottom to the top, gradually becoming smaller in size, and some may disappear.

When boiling, the bubbles produced by the water are small to large, and when they reach the surface of the water, they burst and release a large amount of water vapor. The bubble moves from the bottom to the top, gradually increasing in size until it bursts at the liquid surface.

The reasons for the change in bubble volume before and after boiling are as follows.

Water is heated unevenly when heated, the bottom temperature is higher, and after the bubbles (buoyancy) move upward, they encounter colder water and become smaller in volume (thermal expansion and cold contraction).

After boiling, the temperature is uniform, but after the upward movement, the water depth becomes smaller, the pressure (P=P liquid Gh) becomes smaller, and the internal and external pressure of the bubble should be kept the same (only in this way will it not break), and the volume of the bubble becomes larger.

When the mass of the gas is constant, the larger the volume, the smaller the pressure).

The reasons for the change in bubble volume before and after boiling are as follows.

Water is heated unevenly when heated, the bottom temperature is higher, and after the bubbles (buoyancy) move upward, they encounter colder water and become smaller in volume (thermal expansion and cold contraction).

After boiling, the temperature is uniform, but after the upward movement, the water depth becomes smaller, the pressure (P=P liquid Gh) becomes smaller, and the internal and external pressure of the bubble should be kept the same (only in this way will it not break), and the volume of the bubble becomes larger.

When the mass of the gas is constant, the larger the volume, the smaller the pressure).

When the cold water is just heated, the bubble is getting smaller and smaller when it rises, because the bubble is the air dissolved in the water at this time, because it is just heated, the convection of the water is not too obvious, that is, the lower water temperature is higher, and the upper temperature is lower, so due to the principle of thermal expansion and cold contraction, the bubble is getting smaller and smaller in the process of rising. After the water boils, the bubble is getting bigger and bigger, because at this time the bubble is a large amount of water vapor produced by water boiling, the convection has basically stopped when boiling, the upper and lower water temperatures are basically the same, there is no problem of thermal expansion and cold contraction, but because the pressure of the water increases with the increase of depth, so the bubble is more than above, the smaller the pressure of the water, so that the internal and external air pressure is unbalanced, and the inner air pressure is greater than the outer air pressure, so the bubble will expand and become larger, only to reach the water surface and burst, and the water vapor inside will be emitted into the air.

Why do bubbles go from large to small before water boils, and from small to large when boiling?

When boiling, the distance between the water molecules at the boiling point suddenly increases due to sufficient energy, and the liquid state changes from a gaseous state, and the composition of the bubbles that emerge violently is pure water vapor.

The boiling of water is a violent vaporization phenomenon. At this time, a large number of bubbles rise and become larger, and when they burst to the surface of the water, the water vapor inside is emitted into the air. During the boiling process, although the water is continuously heated, it can only make the water constantly turn into water vapor, and its temperature remains the same.

Water vapour. The water vapor at the bottom and the water vapor above are constantly pooling together and getting bigger.

The change in the size of the bubbles before and after the boiling of water is due to the fact that when the water heats up to the boiling point, the gas molecules inside the liquid are gradually converted into a gaseous state and bubbles are formed.

When the water temperature is lower than the boiling point, the dissolved gases in the water exist in the form of molecules, and the interaction force between molecules is strong, and the gas molecules cannot be assembled to form bubbles. When the temperature rises close to the boiling point of water, the average kinetic energy of the dissolved gas molecules in the water increases, the interaction force weakens, and the gas molecules begin to aggregate to form tiny bubbles.

When the water temperature reaches the boiling point, the average kinetic energy of the gas molecules inside the liquid increases, the interaction force weakens to a certain extent, and the gas molecules are able to overcome the surface tension of the liquid and form stable bubbles. At this point, the bubbles gradually increase and rise from the liquid, eventually reaching the surface of the liquid to burst and release gas.

Therefore, the change in the size of the bubbles before and after the boiling of the water is due to the fact that the dissolved gas molecules in the water gradually aggregate to form bubbles under the action of increasing temperature, and at the boiling point they form stable bubbles and release the gas.

Here's how the bubbles change when water boils:

In the heating process before boiling, because water is a poor conductor of heat, the water temperature of the lower part is higher, and the water temperature of the upper part is low, and the gas is obviously affected by thermal expansion and contraction, so the bottom bubble gradually shrinks during the rising process. And after boiling, the temperature of all parts of the water in the container is the same.

The vapor after water vaporization forms bubbles, and the bubbles are affected by the pressure during the rising process, and the pressure of the water decreases as the water goes up, and the bubbles will gradually become larger.

The bubbles in the liquid before boiling are not the vapors after the liquid has vaporized, but the air that was originally dissolved in the liquid. Because the higher the temperature, the weaker the solubility of the gas in the liquid, so that part of the empty and bright gas that was originally dissolved in the liquid cannot be dissolved after the heat of the Calibre and overflows the liquid.

The bubbles before boiling, the more they reach the liquid, the smaller they become. The reason is that when the liquid is heated, the temperature of the upper layer of the liquid is lower than that of the lower layer, and the solubility of the upper layer of the liquid is stronger than that of the lower layer.

In the bubble, some of the gases that cannot be dissolved in the liquid in the lower layer float to the lower temperature of the upper layer, and dissolve in the liquid again, making the bubble smaller. Most of the bubbles produced before boiling have become smaller and disappear before reaching the surface of the liquid.

The bubble during boiling is the vapor after the liquid has vaporized, and this bubble becomes larger the higher it reaches the upper layer of the liquid. This is because the bubbles in the lower layer are wide and mixed with other bubbles as they float up, making the bubbles bigger and bigger. The bubbles produced during boiling will burst when they reach the surface of the liquid.

After rupture, it forms water vapor with the surrounding boiling water, and after leaving, it is cooled and liquefied into small water droplets, which is the "white gas" we see.

The bubbles get bigger and bigger when the water boils.

After boiling, the temperature of all parts of the water in the container is the same, and the vapor after water vaporization forms bubbles, which are affected by the pressure during the rising process, and the pressure of the water is smaller the higher the water is up, and the bubbles will gradually become larger.

The state of water: 1. Solid.

The solid state that can maintain a certain volume and shape the head of the wheel is ice, snow, frost, and hail.

2. Liquid. A form of matter that can flow, deform, and be micro-compressible, and the liquid state of water usually refers to ordinary water. Liquid states include clouds, rain, fog, dew.

3. Gaseous. The gaseous state is the same as the liquid state, they can flow and can be deformed, but unlike the liquid state, the gaseous state of the substance can be compressed, and the gaseous state of water refers to water vapor.

4. Vitreous.

Liquid water can be transformed into a glass state at about 165 k. The glass state is a cold liquid state, that is, the liquid water remains liquid without freezing below zero degrees Celsius. Glassy water, unlike ice, has no fixed shape and no crystal structure.

It is more like an extremely viscous, solid-state liquid compared to a solid state. The glass density of water is the same as that of liquid.

Under certain temperature and pressure conditions, the state of existence of water can change, which is called phase transition. The high heat capacity of water Compared with other substances, the high heat capacity of water will also make it slowly heat up when it is heated, and it will cool down slowly when it is heated, which plays the role of a natural air conditioner.

The mechanical properties of water people often feel that cotton clothes are very sweat-absorbing and very comfortable to wear, in fact, this is because of the capillary effect of water, so that sweat automatically enters the cotton fiber, thus playing a dry effect. <>