Rain: Cause and Importance (Easy Explanation) Video Lecture - Class 9

hello friends this video on natural
resources part 8 is brought to you by
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this was all about air now let's talk
about another natural resource which is
just present naturally in around us and
that's rain so what comes to your mind
when you think of rain so a rainy day
reminds us of an umbrella or a raincoat
holiday on a rainy day rainy season is
full of water everywhere so what causes
rain so what causes so much of water
suddenly falling down on the earth so
what what causes rain so let's
understand the in that process of what
makes rain happen now when you look at
the water bodies now if you look at
their diet language earth no more than
half of it is covered with water so we
have huge number of water bodies now
during daytime in the presence of Sun
and the water gets heated and when water
gets heated a large amount of water also
evaporates that is the water gets then
voted into water vapor so that's common
now what happens when the water gets
converted into water people now when the
water is getting heated the layer of air
exactly above this water body like that
is the air which is located somewhere
here so that air is also getting heated
now when the air gets heated what
happens that hot air rises up because as
we know hot air is less dense and
anything which is less dense will rise
up now this hot air is not only hot air
the hot air also contains the water
vapor in it like this water vapor which
was formed so the water evaporates so
here in the water bodies you have water
they evaporate to form water vapor at
the same time they heat the air above
the water bodies so the hot air along in
the
the people they start rising up now as
the air starts rising up it gradually
starts cooling down as well because you
know gradually it is going away from
this hot water body so as it rises up it
gradually cools down now as the air
gradually cools down what happens this
cooling causes condensation of the water
vapor into liquid water droplets because
right now what is going up so right now
whatever was going up was basically a
mixture of hot air
plus the water vapor but when they have
gone sufficiently up the hot air start
cooling down so in the hot air cools
down what will happen the water vapor
now the way when you heat let's say you
take water and you heat water so what
will happen evaporation will take place
so water will get converted to water
vapor now similarly if you do the other
way around so if you have water vapor
and if you cool it then what will happen
it will get converted to liquid water
droplets so that is what is happening so
as it has reached at sufficiently height
the air cools down and this cooling
causes condensation of water vapor into
liquid water droplets now where the
where do these liquid water droplets go
so this liquid water droplets they start
accumulating on dust particles which are
present in that most fear so that mostly
you have known of dust particles a lot
so on let's assume here that this black
thing that you see this represents a
dust particle and this is the blue thing
is the water liquid water droplets so on
this dust particle the liquid water
droplet starts accumulating so what
happens you have you had lot of water
vapor here so all of that water vapor is
gradually getting converted to liquid
water droplets so all of these liquid
water droplets gradually you know kind
of condense together they all come
together so they all group together and
gradually they turn bigger and bigger
and this is what that makes the cloud
and when the clouds become big and heavy
enough they fall down as rain rain
because as long as they are not that
heavy
that means they remain at the top as
long as they are not very dense when
they as long as they are less dense the
moment they become very heavy very dense
they tend to come down and how do they
come to come down they come down with
the form of water droplets because cloud
is nothing but the condensed form of
water so basically it is water droplets
okay so then it comes down in the form
of water droplets and that is what we
see as rain now sometimes if the
temperature is extremely low for example
in the hill stations you might have seen
that there is no rainfall rather there
is snowfall that's because the
temperature was so less that these
liquid water droplets were not liquid
water droplets rather they were small
bits of snow or small bits of ice so it
falls in the form of ice so this is how
rain is caused so I hope that this
entire process appeared simple so let's
so let us look at a quick recap of the
entire process of formation of rain so
the first step is water evaporates from
water bodies in presence of the Sun then
this water vapor heats up the air so
this hair get air gets heated up now hot
air is less dense therefore it rises up
now this hot air also contains the water
vapor with it now as the air rises up it
gradually cools now when the air cools
down what happens the water vapor
condenses to form liquid water droplets
these liquid water droplets they get
accumulated on the dust particles which
are present in that mousse fear now the
water droplets gradually turn bigger and
bigger now water droplets when heavy
enough they fall as rain so this is a
simple process by which rains happen now
what's the importance of rain why I mean
is there any importance of rain at all
when rain plays a very crucial role
firstly in agriculture because as we all
know that
for cultivation we need a lot of water
because plants need water water contains
several nutrients dissolved in it and as
a result when this water is taken up by
the plants through their roots that
through this water the plant gets all
the necessary nutrients so water is a
key ingredient for the growth and
development of plants so we need water
so for agriculture in fact even if you
see even today in villages the farmers
they desperately wait for rain so
weather when the rainy season comes
their entire fields get irrigated
secondly rain provides fresh water which
is needed for survival of various life
forms so what it is something which is
needed by all the life-forms so we all
need water right so from Blaine we
actually get some fresh water because
otherwise you might say that up in
oceans also we have so much of water but
that is all saltwater so if we want to
get fresh water from the ocean we
actually need to remove the salt from
the seawater so that is again a long
process a time consuming as well as a
process which involves a lot of cost so
there so that means rain is you know
it's like a direct source of fresh water
and fresh water to something which is
needed by survival of different life
forms whether it is plants animals
insects birds
all of them need water thank you please
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