Conduction Process in Solids, Liquids and Gases HMT Tutorial- 6, Heat and Mass Transfer, GATE Video Lecture | Study Topper Handwritten Notes & Videos for GATE ME - Mechanical Engineering | Best Video for Mechanical Engineering

yes so in this video I am going to share
with you in which type of matter
conduction process can happen so in if
you'll see conduction canwe takes place
in solid in liquid and also in gas
liquids and gases solids right so I have
already shared with you if you have
watch my videos if you haven't don't
worry in this video I'll share with you
how it is happening in solids as well as
liquids as well as in gases so let's get
started with the first one that is
solids so in case of solid what is
happening exactly suppose that we are
having a rod and this is a good
conductor of heat that's why temperature
I mean heat it can fall it can flow
quite easily heat transfer it quite
easily and it does but it quite happen
can quite easily but most important
thing is that this metal must have good
thermal conductivity that's what it does
but it will be much more now suppose
that in this rod is good conductor of
heat right and it's thermal conductivity
is about 100 watt per meter Kelvin
suppose that we are leaving a source of
heat here in this side that's why the
temperature of this side is 100 degree
centigrade and this side is 30 degree
centigrade so according to according to
second law of thermodynamics we know
heat is always flow from higher
temperature to lower temperature so heat
flow would be like this but the question
is this how it is happening or why it is
happening that's it that is the main
reason I am creating this video to make
you understand how heat transfer is
taking place because of conduction in
case of solids the same in liquids the
same in gases if you understand this
concept then you will remember for all
the time why it is happening how it is
happening this is most important these
two questions can
you topper even in the college not only
in the university examination in the
complete examination also so always as
two questions how it is happening and
why it is happening these two questions
can change your life my dear it isn't
that amazing
I don't think so this is not amazing
this is MA this is amazing right so
let's go for it what I am trying to
share with you today then in case of
solids what is happening in case of
solids there are two main reasons
because of those two listens conduction
process is going on what do you want to
know what are those reasons I think so
you wanted to know right so here because
of free electrons free electrons okay
morph electrons will be in the solid the
probability of heat as per rate would be
more thermal conductivity of that body
will be more are you getting my point
now second that's because of lattice
vibration there are two most important
reason that is why heat task what is
taking place in solids if we if you want
to give percentage the latest vibration
because of lattice vibration there is
30% chance or 30 percent 30 percent
contribution of heat transfer and
because of free lake taal 70 percent
contribution of heat transfer so these
two reasons are quite important now one
more thing which is I have already
shared with you but here I am also
sharing for revision or if you haven't
watched those videos at least you will
understand what you will get extra
knowledge about it so what is that if
you'll you know you feel they're two
solid metal one is pure another one is
alloy you know these days we are using
alloy much more than pure probably you
have seen we are using alloy wheel a
motorcycle also so this will see
strength and durability then okay that's
that's fine that's fine that's fantastic
but if you will see thermal conductivity
then pure metal is always much
is having more thermal conductivity than
alloy so this is the most important
thing you need to remember if you are
preparing for complete examination alloy
means brass steel is also alloy pure
metal means copper either these are pure
metal right now I have already share
with you what is solid what is happening
how it is happening I already shared
with you in case of solid I hope you
wanted to know in case what is happening
is of liquid right so let's go for it
liquid so you know this is change and
also new for many that conduction can
also takes place in liquids but my dear
listen to me this is also you know this
is also possible all this is this is
possible that's why I'm sharing with you
because I have also got this knowledge
from my teacher right so what is
conduction process in liquid in case of
liquid what is happening that's because
of you know it is happening that's
because of because of because of you
know that the process and internal other
must say molecules molecules are
directly connected with each other each
other in case of liquid that's because
of that molecules are directly connected
to each other
suppose that this liquid and we have put
it this liquid in up end up in you know
you know you know in a bucket and if we
have supplying heat here if temperature
will be increased here and template
definitely temperature will be increase
in this side and this side having less
temperature then what will happen the
this from this side this in molecule
will start moving to that side molecule
and they will connect with each other
and you know heat transfer process will
takes place that process is known as
liquid conduction thermal conduction in
liquid right now third process third in
gases in giasses so in gases what is
happening and when a white is happening
that's because of molecular momentum
transfer okay
molecule momentum transfer of momentum
transfer of molecule you must say that
also right so if we if we if we if you
wanted to know its concept then I must
say high high velocity and temperature
high velocity and temperature molecules
molecules collide with collide with a
low velocity low velocity and
temperature molecules if high velocity
temperature molecules will collide with
low velocity temperature molecules then
what will happen what will happen there
would be transfer or heat taking place
if there is temperature depends between
one place and another place and this is
the whole process a node is known as
conduction in gases now one most
important concept that is also important
in case of completion if you are
preparing for completion if he had
preparing for completion then I must say
I must share this field with you right
if you prefer competition then must say
you will get caution conduction in
liquids as well as in gases like
companies in this is most important
conduction liquids and gases so if we
will compare then liquid conduction of
liquid is having much more value much I
mean conduction conductivity of liquid
is more than conductivity of gases and
you know probably you know or maybe you
do a you know you will know it you don't
exactly you know we used mercury we used
mercury in thermometer we used mercury
in thermometer you know why we are using
there are few reasons like murky mercury
is low pressure because of low pressure
and because of high density high
conductivity I must say I cannot know
density high conductivity and this is a
liquid but of course this is a matter
liquid metal and you know the thermal
conductivity of mercury is eight point
one what per meter Kelvin mercury right
so mercury is having maximum highest
thermal conductivity mmm liquids and if
you say gases gases having very less
thermal conductivity there is one reason
water is a more thermal conductivity I
mean I'm sorry liquid having no thermal
conductivity than gases because in
liquid molecules are attached together
directly but in gases there is little
bit defense that's why in case of gases
heat transfer is taking place because of
high temperature and high velocity
molecule is collide with high I'm sorry
low temperature and low velocity
molecule that's because of these two
reasons you know that the temperature is
when heat is transferring higher
temperature to lower temperature in case
of gases as well as in case of liquid
now let me share with you another grab
okay so what it what's that gap Delta
will show you thermal conductivity in
gas is okay what per meter Kelvin and
thermal temperature
okay so h2 then helium I must say here
here here having very less thermal
conductivity about 0.026 what per meter
Kelvin we are having way less thermal
conductivity one more things we've
temperature of a temperature if
temperature of gas is temperature of
gases here from here we can understand
that gases will increase the temperature
will increase then thermal conductivity
of gases will also increase but remember
my dear this is I mean if temperature
temperature is increasing thermal
conductivity is also increasing but this
is happening only in case of gas are you
getting my point this is happening in
case of gas only so this is all about
all about and will never about
conduction taking place in solid liquid
and gas okay thanks for watching see you
soon in my next video bye bye