How to write an expository essay on How Rain Comes About 10

Steam. Go to the cloud. Then there is too much rain in the clouds and it rains. If it's cold, it snows, and it's stupid

When the water on the earth is irradiated by the sun's rays, it becomes water vapor and evaporates into the air. When water vapor encounters cold air at high altitudes, it condenses into small water droplets. These small droplets are small, with a diameter of only millimeters and a maximum of millimeters.

They are small and light, held in the air by updrafts in the air. It was these small droplets of water that gathered together in the air to form clouds. For these small droplets to fall to the ground as raindrops, they would have to increase in size by more than 1 million times.

How do these small droplets grow their size to more than 1 million times? It relies mainly on two means:

One is the increase in condensation and condensation.

The second is to rely on the collision and growth of cloud droplets.

In the early stages of raindrop formation, cloud droplets mainly rely on the continuous absorption of water vapor around the cloud body to condense and condense themselves. If the water vapor energy source in the cloud is continuously replenished and the surface of the cloud droplet is often in a supersaturated state, then this condensation process will continue, so that the cloud droplet will continue to grow and become raindrops. However, sometimes the amount of water vapor in the cloud is limited, and the supply of water vapor in the same cloud is often in short supply, so it is impossible to make each cloud drop grow into a larger raindrop, and some smaller cloud droplets have to be merged into the larger cloud droplets.

Rain scene (20 photos) If water droplets and ice crystals coexist in the clouds, then this process of condensation and condensation will be greatly accelerated. When the droplets in the cloud increase to a certain extent, due to the increasing size and weight of the large droplets, they will not only catch up with the slower small droplets in the process of descending, but will also "swallow" more small droplets and make themselves stronger. When the large cloud droplets grow larger and larger, and finally the air can no longer support them, they fall straight from the clouds to the ground, becoming our common rain.

The process of rain formation:

Due to the low temperature of the upper layer of the vapor layer, the volume of water vapor decreases, the specific gravity increases, and the steam falls, due to the high temperature below the vapor layer, the heat absorption during the descent process, it rises again and meets the cold, and then falls, so that the gas molecules gradually shrink, and finally concentrate on the bottom layer of the vapor layer, and form a low-temperature zone at the bottom, and the water vapor is concentrated in the low-temperature zone, which forms a cloud. The clouds gradually become larger, the convection up and down inside the clouds becomes more and more intense, the temperature becomes lower and lower, and finally raindrops fall.

Classification of rain:

1 According to the causes of precipitation:

Convective rain, frontal rain, topographic rain, typhoon rain (cyclonic rain).

2 According to the amount of precipitation:

It is divided into 6 levels: light rain, moderate rain, heavy rain, heavy rain, heavy rain, and extremely heavy rain.

Light rain: mm 24 hours.

Moderate rain: 10 mm for 24 hours.

Heavy rain: 25 mm for 24 hours.

Heavy rain: 50 mm for 24 hours.

Heavy rain: 100 250 mm 24 hours.

Heavy rain: greater than 250 mm in 24 hours.

Benefits of rain

1. Rain is an indispensable part of the earth, and it is the only way for almost all terrestrial plants far away from rivers to replenish fresh water.

2. Rain can irrigate crops and is conducive to afforestation.

3. Rain can reduce the dust in the air and reduce the air temperature.

4. Rain is conducive to reservoir water storage, can replenish groundwater, can replenish river water, is conducive to power generation and shipping.

5. When it rains, you can isolate the noisy world and create a peaceful environment, which can be hypnotized and washed the streets.

6. Rain can wash away garbage on the ground, dilute toxic substances, and purify the environment.

7. Rain can extinguish fires.

8. It can create a romantic atmosphere.

9. You can cleanse yourself.

The bad side of the rain

1. More rain will affect the growth of plants, inhibit the respiration of plants, and even die.

2. In the middle and lower reaches of the Yangtze River in China, there will be a long period of gloomy and rainy weather during the rainy season, when all things are very easy to get damp and mildew.

3. When thundershowers come, there are often weather phenomena such as strong winds and thunderstorms. When the wind comes, the sand and rocks are scattered, and the roof is blown down and the wall is blown down. In the wind and rain, things in the street dance in the wind, fly everywhere, and even uproot big trees.

4. Continuous rainy days will also affect people's emotions, making people feel bored and depressed.

5. Raining too much will lead to traffic jams, causing natural disasters such as landslides and mudslides.

6. Rain will erode many buildings.

7. Cause the road to slip, thus causing a car accident.

8. Rain will bring toxic substances in the soil into the groundwater, thereby polluting the groundwater.

1. Rainy season (frontal rain): Warm and moist air currents from the ocean meet cold air from the land. Because the cold air is heavy and the warm air is light, the warm and humid air flow is forced to rise, and when it encounters condensation, it forms a very long and wide rain band, forming a frontal rain.

2. Convective rain: In summer, under the strong sunshine, the warm and humid air in local areas rises sharply, and when it is condensed, it forms noisy rain.

3. Topographic rain: The warm and humid air flow from the ocean, when it encounters mountains, is forced to rise, and when it encounters condensation, it forms rainfall.

Rain is formed through three stages. First of all, the "raw material" of rain, that is, water vapor, is lifted into the air by the wind to form clouds, which in turn form rain and fall to the ground.

The first stage, movement: the cloud is driven by the wind at its location, i.e., moving.

The second stage, unionization: these small patches of clouds, propelled by the wind, unite in a certain area to form a new, larger cloud.

Stage 3, Accumulation: After the small cloud patches unite, the upward gravitational pull within the large cloud mass increases. The upward gravitational pull at the center of the cloud is stronger than the gravitational pull at the periphery.

These upward gravitational pulls cause the cloud to expand vertically. In this way, the clouds expanded upwards and converged one by one. At the same time, it causes the cloud to extend to a relatively low temperature.

As a result, the water droplets and hail particles on the cloud begin to increase. After the above phases, the water droplets and hail particles gain weight so that the upward gravitational pull cannot support them. Eventually, it rains and hails from the clouds to the ground.

Wang Tsai knows all about Astronomy-03 "How is a meteor shower formed? 》

1. Rain is the evaporation of water on the surface of land and sea into water vapor, and the water vapor rises to a certain height and becomes small water droplets when it is cold, these small water droplets form clouds, they collide with each other in the clouds, merge into large water droplets, and when it is so big that the air can not support it, it falls from the clouds and forms rain. The main component of rainwater is water, with a small amount of sulfur dioxide and nitrogen dioxide, usually the pH value of rainwater is about, and the rainwater with a pH value less than is acid rain.

2. The causes of rain are varied, and its manifestations are also distinctive, including drizzle, continuous rain, and downpour showers. Rain usually comes in four forms: frontal rain, convective rain, topographic rain, and typhoon rain.

Rain is a natural precipitation phenomenon, the most important freshwater resource in human life, and an indispensable part of the earth.

In a water cloud, the cloud droplets are all small droplets. They are mainly increased by continuing to condense and colliding with each other. Therefore, in a water cloud, for the cloud droplet to increase to the size of a raindrop, the cloud first needs to be very thick, dense, and watery, so that it can continue to condense and grow; Secondly, there needs to be a strong vertical motion in the water cloud, so as to increase the chance of multiple collisions and merging.

In the thinner and more stable water clouds, the cloud droplets do not have enough opportunity to condense and merge and grow, and can only cause cloudy, cloudy skies, and little rain.

The distribution of the size of the cloud droplets varies from one cloud to another, and the reason for the uneven size of the cloud droplets is the transfer of water vapor in the surrounding air and the evaporation of the cloud droplets. The factors that make the cloud droplets grow are the condensation process and the collision merger process, in the case of only condensation, the size of the cloud droplets is uniform, but due to the replenishment of water vapor, some cloud droplets grow, plus the result of the merger, the larger cloud droplets continue to grow and become larger into raindrops. Raindrops fall by gravity, and when there is an updraft, an upward force is applied to the raindrops, slowing them down, and some small raindrops may be carried up.

Only when the raindrops increase to a certain extent can they descend to the ground and form rainfall.