L1 - States of Matter - Matter in our Surrounding, Class 9 , Science Video Lecture

matter since early times human beings
have been trying to understand the
surroundings as we look at our
surroundings we see a large variety of
things with different shapes sizes and
textures everything in this universe
that we see is made up of material which
is called matter matter occupy space and
has mass all matter is made up of tiny
particles if we were to observe sunlight
falling through a window we would be
able to see tiny particles floating in
the air these particles have spaces
between them let's demonstrate that
using the example of salt dissolved in
water when we dissolve salt in water the
particles of salt get into the space
between the particles of water also you
will observe that there is no change in
the water level thus we have found that
particles have space between them you
will also see that the particles
continuously move a drop of ink slowly
spreads in water matter around us exists
in three states solid liquid and gaseous
matter in the solid state has definite
shape and volume this is because the
particles in solid are tightly packed
fit together in a regular way and there
is no big space between the particles
therefore the force of attraction
between the particles is very strong and
the only movement they make are tiny
vibrations to and fro that is why solids
are rigid and retain their shape if we
take a stone and put it in a box the
pebble retains its shape matter in
liquid state has no fixed shape but has
a fixed volume in liquids the particles
are most closely held together but are
not in a fixed pattern particles move
freely and have greater space between
each other because of the greater space
between the particles the force of
attraction between the particles is
weaker than in the solid
matter in geisha state has no definite
shape and no definite volume in the
gaseous state the particles are far
apart there is a lot of space between
the particles and they move about
randomly at high speeds due to the huge
space between the particles there is no
force of attraction when a stone is
dropped into a beaker with water why
does the stone sink into the water let
us explore generally the density of
solid is high compared to liquid and gas
because there are not big spaces between
the particles gases have much lower
densities than either liquids or solids
let us examine compressibility another
attribute of matter these are empty
syringes close the nozzles of the
syringes with rubber fill one
syringe with chalk pieces fill another
with water and leave one syringe empty
insert the piston and try to compress
the material in the syringe you will see
that the syringe with the solids is not
compressible because the solids are
rigid the syringe with water is
compressible because there is greater
space between particles compared to
solids the syringe which is empty is
easily compressible because the
particles in a gas in this case the air
in the syringe have more space than
solids and liquids this experiment shows
that gas is highly compressible compared
to solids and liquids yet another
attribute which differentiates solids
liquids and gases is diffusion
when perfume is released into the air
the fragrance spreads very fast this is
due to the movement at high speed of
particles and the large space between
them thereby gasses show the property of
very fast diffusion liquids have less
diffusion when compared to gas in solids
diffusion is negligible
things to remember mattered exists in
three states solid liquid and gaseous
solids of definite shape and volume
liquids have no fixed shape but have a
fixed volume gases have no definite
shape and volume the spaces in between
the Constituent particles are minimum in
the case of solids intermediate in
liquids and maximum in gases the forces
of attraction between the particles are
maximum in solids intermediate in
liquids and minimum in gases generally
density is very high for solids moderate
for liquids and much lower for gases
generally compressibility and diffusion
are negligible in solids moderate in
liquids and very high in gases
you