Properties of Soil - Soil - CBSE Class 7 Science Video Lecture

good morning children
today we shall learn the properties of
soil and why there are different types
of soils if a farmer wants to grow
tomato would he be able to grow it
without soil well as we know every crop
requires certain type of soil if someone
has a piece of land he needs to know the
soil otherwise he might sew wrong seeds
which wouldn't grow into a plant you may
have a garden space but if you don't
know about the type of soil you can't
make a nice garden you know there are
many things that make the soil fault
I'll let us take a little fertile soil
from a garden and find what it has first
we takes the soil in a container and
cover it with a lid then we heat the
container if the sunlight is intense we
can also keep the container outside in
the direct sunlight for few hours then
we open the lid look there are drops of
water on the lid where did it come from
well the soil contains water and when we
heat the container that 4 turns into
vapour later the water vapour touches
the lid and cools down to form water
droplets so this shows soil has water
the plants absorb this water through its
roots now we take some soil in the
container and pour water over it look
some air bubbles are forming it shows
that a soil contain air when we pour
water the air which was trapped in small
gaps between the soil particles escapes
in form of a bubble this air in soil
provide oxygen to the roots of the plant
for
many animals which live in soil like
earth warm etc use the air trapped in
soil for breathing the ability of
holding water and air is not same in
different soils if we just look around
we can tell there are different kinds of
soil but why are they different we need
to know what soil consists of in order
to know the difference between the
various soils let us take handful of
soil from the garden let us take a glass
tumbler and fill 3/4 part of it with
water we then add some soil into the
water and still the water with a stick
don't disturb the water for next few
minutes look three different layers are
formed this layer are formed from
different particles of the soil the
bottom layer consists of small gravels
that is stones and pebbles about that is
the sand layer and above the sand layer
there is a layer which consists particle
which are smaller than sand this is
called clay so clay is the smallest
particle in the soil look something is
floating on the water look closely you
may find dead leaves decayed organic
substances etc this is Yuma's you must
provides nutrients to plants and makes
the soil fertile so now we know in
general soil consists of small pebbles
or gravels it also contains sand clay
and other particles to the air and water
are also present in the soil the
deadliest decayed organic substances
found in the soil form the fertile
humors
if a soil has the right structure to
trap air water in it and has the right
amount of you must to provide nutrients
to the plants it would be fertile
you know earth warm lives in soil and
makes the soil loose and then soil can
trap more air and water can also enter
the soil easily so no wonder the earth
warm is known as a farmers friend that
is all for today children bye-bye