How does rain form? How does it fall to the ground?

Arab Weather - Despite what we see of water evaporation and its decrease in some places, the amount of water available on the earth is constant, due to the water cycle that transforms the water from its liquid form to the gaseous form (steam), then it returns to the ground in its liquid form, where the energy is heated The heat from the sun is liquid water, giving it enough energy to break down its molecules and turn them into water vapor.

How do clouds form?

Water vapor is one of the basic components of the air in the atmosphere, and the warmer the air, the more water vapor it can carry, and when this warm, moisture-saturated air (water vapor) rises to the upper atmosphere it cools, and when the air cools to less than The dew point, condenses around "condensation nuclei", which are usually very small particles of dust, smoke, or even salt suspended in the air.

These tiny droplets of water form clouds or clouds, and if you watch clouds in the sky, you will see that they are shrinking and increasing continuously in response to the alternating process of evaporation and condensation.

How does rain come from clouds?

When the water vapor condenses into small droplets and forms clouds it may become rain, but if the water droplets are very small, the air currents will keep them in the upper atmosphere, but as these drops continue to rise, supported by more warm air rising, they have two ways to return to Earth :

• The first method is for water droplets to collide and combine with other drops, eventually becoming heavier than the air can carry, at which point they fall in the form of rain .

• The second way is for the air to push the water droplets upwards and they rise, and when the drops are high enough they freeze and turn into crystals of ice, and attract more water vapor to them, so they grow quickly until they become heavy enough to fall in the form of snow, or melt and fall in the form of liquid rain Where the weather conditions determine the shape in which water droplets fall, between snow, hail, ice grains mixed with rain, or liquid raindrops.

Different forms of precipitation

The form that precipitation takes when it reaches the ground depends on the temperature in the clouds, the temperature on the ground, and the air temperature between them. There are four different forms of precipitation:

• Liquid Rain (Rain): occurs when the degree of cloud temperature and the temperature of the Earth above freezing, and can take three forms, where it is known as the Rain (Rain) when the diameter of drops about 0.5 mm, and be in the form of spray (Drizzle) when they are droplets smaller than that, and the third figure is Elvirja (Virga) occurs when droplets are too small so they do not reach the ground.

• Snow (Snow): occurs when the temperature in the clouds and on the ground less than the freezing temperature of water, less than zero percentile, then water droplets become intense and ice crystals fall to the ground Ktheloj.

• Freezing rain ( Sleet ): sleet occurs when the temperature in the clouds is warmer than the temperature on the ground. The water droplets fall as rain and partly freeze on the way, bringing the precipitation to the ground in the form of a mixture of snow and water .

• Cold (Hail): Sometimes water droplets rise to the top layer of air frozen, Vtaatsalb to drop the size of the rain - icy granules or larger - known as the cold, which reaches the earth in the form of cold , even if the earth 's temperature is higher than the freezing point, where Hail is a common feature of severe thunderstorms in summer .

How does rain differ from one place to another?

The shape of rain is affected not only by weather conditions such as air temperature, but also by land formations. For example, rain is often more in mountainous coastal areas than in flat coastal areas, because when the moist air coming from the ocean rises to cross over the hills, it condenses enough to turn into Rain.

And some of the most spectacular rain can occur when air fronts collide, or masses of warm and cold air, and when that happens, the mass of warm and moist air rises up above the air of the cold front, and as all this warm air rises, it cools enough until the water vapor condenses and falls on The form of heavy rain, and summer thunderstorms are formed by the same mechanism when the appropriate conditions are available.