What are the conditions for cloud formation? Causes and conditions of cloud formation How clouds are

In nature, clouds are visible polymers floating in the air composed of small water droplets or condensed Xiaoice crystals formed by the liquefaction of water vapor in the atmosphere when cold. Three conditions are required for its formation: the presence of water vapor in the air, a decrease in temperature, and the presence of condensation nuclei in the air.

Physics] [Liquefaction, Sublimation and Condensation] - How are clouds formed?

Under the light, the evaporation of water surfaces and plant leaves such as rivers, rivers and oceans produces a large amount of water vapor. Affected by the temperature of the atmosphere below the boiling point of the water surface, the water vapor content changes greatly in the atmosphere, thus showing various forms, and clouds are one of these forms.

In the atmosphere from the ground upwards, the closer to the ground, the higher the temperature and the denser the air; Conversely, the higher you go, the cooler the temperature and the thinner the air. When water vapor enters the atmosphere, the thinner the air rises as the altitude increases, and the lower the air pressure, the rising water vapor expands due to the decrease in volume and the specific gravity increases.

Since the expansion of water vapor consumes its own heat, the temperature in the rising air decreases. As the temperature decreases, the ability of the atmosphere to hold water vapor becomes less and less. When the temperature drops to a certain level, the air is saturated with water vapor.

At this time, if the air continues to rise, excess water vapor will precipitate.

When the temperature in the atmosphere is higher than 0 during the rise of water vapor, the excess water vapor will condense into small water droplets. When the temperature is below 0, the excess water vapor is condensed into Xiaoice crystals.

When these small water droplets and Xiaoice crystals gradually increase and "come together" together to reach a certain number, a cloud is formed that can be seen through the naked eye.

In addition to the two basic conditions of sufficient water vapor and air cooling, there is also one of the most critical factors, which is "condensation nuclei".

If the air is free of any impurities and is absolutely pure, the water vapor molecules in the atmosphere cannot attach to the condensation nuclei.

The "adhesion" between individual water vapor molecules in the atmosphere is very small, and due to the limited ability to merge with each other, they are finally "together" together and then "separated". Even the small fraction of water vapor molecules that come together by eliminating all odds will be so small that the small droplets will evaporate rapidly. Therefore, their efforts can be described as "all the work they have done".

The atmosphere contains a large number of particles, typically dust, as well as a large number of tiny particles such as salt and smoke particles, which are called "condensation nuclei".

Condensation nuclei play a particularly critical role in the formation of clouds. It not only condenses and gathers a large amount of water vapor, but also makes them attach to itself.

As a result of the condensation nucleus, a large number of water vapor molecules that collide and join together are finally "agglomerate", and they "break into wholes" to form clouds of different sizes.

1. The water on the ground absorbs heat and turns into water vapor, which rises to the upper layer of the sky vapor layer. Due to the low temperature of the upper layer of the steam layer, the volume of water vapor decreases, the proportion increases, and the steam decreases. Due to the high temperature below the vapor layer, the jujube heat is absorbed during the descending process, and then rises again to meet the cold, and then descends, and so on, which forms a cloud.

2. Clouds absorb the heat emitted from the ground and reflect it back to the ground, which helps keep the earth insulated. But the clouds also reflect sunlight directly back into space, which has a cooling effect.

3. Which effect prevails depends on the shape and position of the cloud. In this layer of the atmosphere more than ten kilometers from the ground, the closer to the ground, the higher the temperature, the more abundant the air; The higher you go, the cooler the temperature and the thinner the air.

4. On the other hand, the water surface of rivers, lakes and seas, as well as the water of soil, animals and plants, evaporate into the air and turn into water vapor.

Cloud formation is mainly caused by condensation of water vapor.

Clouds floating in the sky are made up of many tiny water droplets or ice crystals, and some are made up of small water droplets or Xiaoice crystals mixed together. Sometimes it also contains some large raindrops, ice and snow particles, and the base of the cloud does not touch the ground and has a certain thickness.

Cloud formation is mainly caused by condensation of water vapor. We all know that in this layer of the atmosphere more than ten kilometers from the ground, the closer to the ground, the higher the temperature and the denser the air; The higher you go, the cooler the temperature and the thinner the air.

On the other hand, the water surface of rivers, lakes and seas, as well as the water of soil, animals and plants, evaporates into the air at any time and becomes water vapor. When water vapour enters the atmosphere, it becomes clouds that cause rain, or condenses into frost and dew, and then returns to the ground, seeping into the soil or flowing into rivers, lakes and seas. Later, it evaporates (sublimation) again, and then condenses (condensation) and declines.

The cycle goes on and on.

After the vapor enters the lower atmosphere from the evaporation surface, the temperature here is high, and the water vapor contained is more, and if the hot and humid air is lifted, the temperature will gradually decrease, and at a certain height, the water vapor in the air will reach saturation. If the air continues to be lifted, excess water vapor will be precipitated. If the temperature there is higher than 0°C, the excess water vapor condenses into small droplets; If the temperature is below 0 °C, the excess water vapor condenses into Xiaoice crystals.

When these small water droplets and Xiaoice crystals gradually increase to the point where the human eye can recognize them, they are clouds.

1. When the sun shines on the surface of the earth, water evaporates to form water vapor, and once the water vapor is supersaturated, water molecules will gather around the dust (condensation nuclei) in the air, and the resulting water droplets or ice crystals scatter sunlight in all directions, which creates the appearance of clouds. In addition, clouds can take on a variety of shapes, and they are divided into many types depending on the height and shape of the sky.

2. Long-term observation and practice have shown that the generation and dissipation of clouds, as well as the evolution and transformation between various types of clouds, are carried out under certain conditions of water vapor and atmospheric movement. People can't see water vapor and can't see atmospheric movements, but they can see every move of water vapor and atmospheric movement from the evolution of clouds, and water vapor and atmospheric movement play an extremely important role in weather phenomena such as rain, snow, ice, and hail.