HOW DOES IT RAIN ?

7] HOW DOES IT RAIN ?

We all know that clouds give us

rain. Whenever the sky is covered

with dark clouds, we know that it

is going to rain. The formation of

raindrops in clouds is a long and

complicated process of nature.

Let's see how this happens.During summers, the water ofriver, lakes, seas and ocean gets

converted into vapour by the heat

of the Sun. This vapour mixes with

the air and makes it hot and

humid. Since water vapour islighter than air, they keep rising in the sky

and even a slight decrease in the surrounding

temperature transtorms them into clouds

We know that there are dust particles in the

air. When clouds move from hotter regions

to colder ones, water vapours start

condensing on these dust particles, forming

droplets in the clouds.

Only when the size

of these droplets increase due to further

condensation, they start falling down on theEarth as rain due to the force of gravity.Thus, for rain to occur, it is essential

that hot and humid air should move up so

that water vapour gets Condensed. Lifting

of air takes place in several ways such as

orographic lifting, frontal lifting and

convectional lifting.

Orographic lifting occurs

when air is forced upwards by a natural

barrier, like a mountain, which may come in

its way. In frontal lifting, Cool air mass is

pushed up by a hot mass of air from beneath.

Convectional lifting occurs due to currents

caused by the heat of the Sun. Do you

know that the highest rainfall of the world

takes place at Cherrapunji (Assam) in India?

The average annual rainfall of this place is

1,200 centimetres. In 1861, the total rainfallrecorded here was 2,175 centimetres.In colder regions, condensation of water

vapour takes place not only on the dustparticles, but also on the small particles of

ice formed in the clouds. Condensation also

takes place on ions produced by lightning

in the air. Water condensed on ice

particles also falls down on the Earth in the

torm of hail.