Termodinamika Kuliah 1 - Pendahuluan dan Konsep Dasar

Hello, welcome to the

thermodynamics course and this is the

first lecture which is about the introduction and

basic concepts So there are five contents that

we will discuss in this video in

this first lecture, the first we will

discuss the definition of thermodynamics and

its relationship to energy Then the

second we will discuss the system and

control volume, the third we will

discuss the properties of state and

equilibrium, the fourth we will

discuss what is the process and cycle, the

fifth we will discuss the zeroth law of

thermodynamics so in

this first lecture we will discuss more

Emm terms and also vocabulary that

we will use throughout the

thermodynamics lecture, yes Well here there is

one example in the picture on

the right, this is an example of the

application of thermodynamics, namely

Power

Plan or power plant, yes, so

thermodynamics is a

science that is actually very close

to our lives, so we will

discuss some important vocabulary and terms,

yes In this first lecture

Well, we will discuss from the term, yes,

or from the name of thermodynamics,

so thermodynamics can be

defined as the science of energy

So if statistics is the science

of data, yes, while thermodynamics

is the science of energy In essence we

discuss all forms of ee

energy changes, yes, it is a study

of thermodynamics, well, then from the

root of the word thermodynamics comes from

Greek, namely terme which

means heat or color and dynamic yes

or dynamis yes which means power, so

e thermodynamics is actually from the beginning of

e the development of human civilization, it is

a science that discusses the

conversion of heat

into power or work into power or

work, yes, One of the discoveries or

one of the tools that ee the first time

thermodynamics was used, it seems, is

ee the steam engine, yes, it converts heat

into power or work, which is

one of the markers of the

industrial revolution, well, what we will discuss throughout

eh the thermodynamics course

are the laws that are indeed the laws

of Thermodynamics, the

first is the first law, yes, the

first law of thermodynamics, this is

none other than the law of conservation of energy,

yes, and energy is a quantity or

property of thermodynamics, yes, And we

have studied together even in elementary school, yes, elementary school, junior high school,

high school about the law of

conservation of energy, yes, so if ee there is

one object above ee one height H,

yes, then he has

ee potential energy yes that is mgh yes

then he will change ee

this potential energy when the object

falls into kinetic energy yes 1/2 MV

p^ Well that is more or less the law of

conservation of energy yes in ee mechanics

Well here we will also discuss later the

first law of thermodynamics in

relation to the law of conservation of energy, namely the

relationship between work then there is heat

then there is internal energy yes

we have actually studied all of them in high school

but in thermodynamics in this lecture in

engineering we will deepen

from ee the law of conservation of energy

yes Well the first law of thermodynamics

deals more with the titas yes quantity quantity

while eh for

this second law discusses more about the quality of

energy Well this may be something that is still foreign to

our ears maybe yes when we

first studied thermodynamics e

in engineering or on campus or at

university yes that we will discuss the

quality of energy and not just

quantity yes so the second law of

thermodynamics will be related to

entropy yes E where the second law of

dynamics states that energy

not only has quantity but

also quality and the conditions for a process to

occur are that it takes place in a direction where

the quality decreases yes So it does not

increase so naturally ee energy

will flow from

higher quality to lower quality energy

yes For example, there is

one picture on the right side of

this slide yes there is one or a cup of

coffee yes if this is coffee

that may have just been served yes in a

cafe Let's say He has a temperature of 70

degrees Celsius yes Well 70 degrees

Celsius we can interpret this as

temperature yes if we put the temperature

there thermometer there we put the

temperature sensor yes it reads 70 degrees

Celsius yes Well this is one ee

quantity later yes quantity or

property we will study later namely ee

temperature but here of course there are

many ee water molecules yes water molecules

then there are many particles that

move and

EE this collective movement

causes the coffee to be hot yes Well

in this coffee there is energy yes Well

there is energy that will move to the

environment yes so if this cafe

Let's say it has air conditioning He has a temperature of 18

to 20 degrees Celsius then

the coffee itself is 70 degrees Celsius and

in our daily lives we

know that there will be a flow of heat yes

Q with the symbol q yes E there is a flow of

heat from this coffee to the environment in

this case is yes cafe So

if the first law of thermodynamics

states that in this coffee

there is energy, namely the quantity, the

second law of thermodynamics states

that there will be a flow of energy from

higher quality energy, namely

in this case coffee, yes, because its quality is

higher. It has a

higher quality and value ee compared

to the environment, yes, so there

will be a flow of heat, yes, from the

EE temperature is higher to the temperature is

lower or the quality is

higher to the quality is lower, yes,

why is it called a

higher quality, yes, because with

this 70 degrees Celsius heat, if we

convert it into work later with the

symbol W, yes, maybe it should be white

with the symbol w B, yes, then the work of 70

degrees Celsius will be much

greater than the 18 to 20

degrees Celsius, yes, and that is nothing other than

the principle of

thermodynamics itself, yes, namely converting

heat into power or work, the

higher the heat, the greater

or better we can

convert it into ee power or work, yes,

Well, the second law of thermodynamics states

that there will be a flow of heat and from

or there will be a flow of energy from the

higher quality to the

lower and Not on the contrary, yes,

for example,

Ee, we cannot heat this coffee to

70 degrees Celsius by taking

heat from outside. Is that right or not?

If, for example, Ee, we might

do it, then it is a violation, yes, if

someone says that, Okay, if I

have coffee at 70 degrees Celsius in

the environment or in a room that is 18

to 20 degrees Celsius, then I can

make

this temperature lower, let's say it

becomes 15 degrees Celsius, then

this 70 degrees Celsius rises, let's

say it becomes 75 degrees Celsius.

Well, this is a process that is

impossible in our

daily lives. Well, this process can be

done if we

add work from outside. Well, that is the

ee principles that

we will learn throughout

this course, yes, this is an

everyday example, but from this everyday example,

we can know that thermodynamics

is in our daily lives,

which we sometimes take for granted. Well,

hopefully after studying this, we will

no longer take it for granted, we will start

to think more deeply,

so we can study every

phenomenon that is around us and

can use it for applications in

our lives. Okay, let's continue the

study of thermodynamics. it is divided

into two, namely classical thermodynamics

which will be the discussion of

this course, yes, or in this video or in this

series of videos, yes, so

this course, yes, or this series of videos, if

you are not my students

who are ee enrolled or registered at

Unpar, yes, throughout the playlist of

this course, we will discuss only

classical thermodynamics, yes,

this classical thermodynamics is a

thermodynamic approach that does not

need to take into account the behavior of the

constituent particles, yes, So you could say that

this classical thermodynamics is a much

more

macroscopic study, yes, macroscopic, yes, for example,

we will calculate or yes, measure Yes,

if in the practicum in thermodynamics,

we will make measurements or

we calculate P, yes, which is

pressure, then there is another quantity, ee,

namely

volume, yes, then there is another one, namely

temperature, now this is the most frequent

quantity that we will calculate ee

in thermodynamics, yes, what is interesting

is There is a second study, namely

classical or statistical thermodynamics Oh,

sor, namely statistical thermodynamics, yes,

this second study,

statistical thermodynamics, is a

thermodynamic approach that takes into account the

average properties of the constituent particles, so It

can be said that

statistical thermodynamics is a

more microscopic study, yes. For example,

if in classical terminodynamics it

discusses pressure, yes, then in

statistical thermodynamics, yes, it discusses

pressure in the form of collisions between

particles, so let's say I have a

piston or a vessel, yes,

then I press it, yes, or

just a piston, yes, I press it, yes, here there is

a part that can press the

fluid, yes, then inside

here there is the fluid, yes, and in

the fluid, the liquid or gas, so this

can be a liquid or gas,

yes, the liquid and gas certainly

consist of atoms and molecules, right or

not, yes, Therefore, I give

an illustration here, yes, there are molecules

and atoms that EE, let's say it is a

gas or liquid, yes, and in

statistical thermodynamics, if we look at it in a

much more microscopic form of pressure,

yes, so if we press it, of course there

will be an increase in pressure, yes,

because I press it, I compress

it, yes, so the pressure increases, yes, the pressure increases,

the volume decreases, yes, and that is

a relation that we often use

in everyday life, so

the pressure increases, then the volume

will decrease, yes, And if I only

measure or calculate the pressure, then

I studying thermodynamics

classically but if I look at

each ee particle of course the

particle will move and will

start to press yes parts of

the wall right so if I

zoom in there is one molecule that starts to

press to the right ee Sori down

then there is a molecule that presses to

the right yes to the right wall then

there is a molecule that also presses up

because it starts to be pressed by part of the

piston then I calculate the

average here I calculate the average

of the collisions yes so the

average of the

collisions yes or ee momentum yes momentum

of the collisions yes Well this is what

will collectively

determine the pressure that we

calculate Okay so once again the

classical thermodynamics that we will

discuss throughout this course or

throughout this video playlist is

the macroscopic one yes which is the

result of the motion of the constituent particles

without having to take into account the

behavior of the particles so

we just calculate the p yes the pressure

or we just measure in experiments

for example without having to know that there are

how many particles EE

have collisions so much then

how many particles have e

momentum so much yes sor not collisions

should be momentum, yes, how much is it, right?

Well, while classical thermodynamics, yes,

we can make a graph here,

for example, there are a number of e particles,

here it should be, for example, momentum, yes, Ee

momentum, momentum p-nya P ee, meaning p

p momentum, yes, m * v, yes, then on the

y-axis there is the number of particles, yes,

of course it is not uniform, there are those with large e

momentum, then maybe

ee is in the middle of the value, then

there are also smaller ones, they are

higher, yes, this is eh, each

particle that we actually calculate

statistically How many particles

have a certain momentum, how

many particles have a

certain momentum, yes, then we take the

average and it turns out that this is actually

one entity or one quantity or one

property, later we will study it which is

called pressure, yes, so

our study is classical thermodynamics, yes,

hopefully this example can help What is the

difference between classical and statistical, okay, well,

next, we will probably

study together Later in

this course, there are applications of

thermodynamics, yes, and in

everyday life, we see this application,

the first is a refrigerator, yes,

this refrigerator, ee, transfers

heat, yes, transfers heat from the inside,

so transfers heat from inside yes

because if I have a drink that is EE

in room temperature or food in

room temperature I want to make it

cold yes and that means from hot

to cold yes now if you have

Ee learned thermodynamics you should

understand better yes that from something

hot to cold it means we

take heat yes that

means

we

take heat Okay so there is a

refrigerator yes a box like this yes the

equipment is quite

em yes quite sophisticated yes Ee with ee

refrigerant then ee with compressor

and so on yes then I have

food yes with tea temperature for example

then I want to make the food

to a lower temperature

which means I take heat from

ee the food I throw it out

or into the environment yes And if we

look here t t which is outside here

Suppose t outside from ee the refrigerator

or from the refrigerator is

higher right or

not I is higher Let's say yes

for example if in my house there is 25

degrees Celsius then I have

food which was ee 25 degrees

Celsius too then I can

lower it to around Let's say ee

a dozen yes maybe 12 to eh 15

degrees Celsius if in a

regular freezer, yes And if we look at it together

How can it violate the second law of

thermodynamics Is it true or not because

it should flow from a

higher temperature to a lower temperature,

yes And if we look here

Why is it possible that this refrigerator

has power, yes, surely He, ee,

if the refrigerator is functioning properly, yes,

he takes power from outside, yes

Therefore, later we will learn

together Why can a device

seem to violate the second law of thermodynamics,

yes, because it is possible if

there is power from outside, yes Well, this may be a

little story about

this application, later we will learn

more details about the refrigerator, yes

Then the second is the Pressure Cooker,

yes, this Pressure Cooker is a cooking tool

that can cook much

hotter, much faster than

the usual cooking method, yes, namely, we,

ee, we, ee, cover it with one, ee, a pan

or a pan that is under high pressure

so that the heat contained in the pan

will be much higher, yes,

then in terms of energy, yes,

power plants, ee,

fossil energy, there is Power PL, yes, fossil energy,

then even to the point of ee, studies from

power plants with energy

renewable in this case wind turbines yes

it is also an application of

thermodynamics yes then what we will

also discuss is about car engines yes

there are two strokes then there are four strokes yes

two strokes and four strokes later we

will see together yes Why is there

a fuel that when burned

then put in a mechanism

ee machining can make an object

move yes all are applications

of thermodynamics yes okay now

we discuss one or so many

vocabularies yes and terms in

Thermodynamics the first is called a

system the second is called the

environment yes and the third is

called the boundary yes so ee

this system is the quantity or material that

we study yes so that is what is called a

system yes So if I have

one object yes one object or I make

ee discontinuous Like this Well if

this one object I I I I Study yes

then I want to know ee its nature

I want to know its characteristics

then I want to know the

thermodynamic quantities yes then this is called a

system that we are ee

reviewing yes that is from ee the system

yes then what is outside the system yes

what is outside the system is the

environment yes so the environment is

an area that is in outside the system

or what is called

surroundings in English okay well

eh the boundary between the system and the

environment or real or

imaginary surface yes that is what is called a

boundary yes yes So

this dotted line is the boundary yes Well

then in simple analysis we

assume that the boundary

has zero thickness yes meaning it

has no thickness it also has no

mass and no volume yes to

make our analysis easier in

everyday life or in ee analysis which is

rnya Yes of course we have to take into account

from this boundary but in the

simple study of Thermodynamics which

we will discuss throughout this course

we assume that this boundary has no

mass has no thickness yes and

also has no volume Okay Well there is something

called a fixed boundary or

fixed and a moving boundary yes if the

boundary is fixed Yes we both know

that ee This is a boundary that does

not change yes for example I

have ee a box yes a cube yes ma'am

like this then I assume

as this is my system so this

is the

system then what is outside is the

environment yes then these boundaries are

fixed Yes meaning it is rigid yes a

rigid object yes which indeed

Ee cannot move yes Well this is a

fixed boundary or fixed yes but

boundaryy also or limit also it can

be a moving limit for

example piston yes so piston piston

cylinder Suppose like this yes

then He has

ee one

em is it possible in one form can

Elis shape can be round yes which can

move up and down yes when it goes down

yes then ee fluid pressure inside ee

piston increases volume

decreases yes And if it goes up yes if it goes up

then the pressure decreases and

the volume increases yes so the limit

can be a fixed limit and a

moving limit yes Well this is a

ee concept that must be mastered Okay

Well then there is something called a

closed system yes which is called

mass control well in

this system ee no mass

exchange is allowed yes mass exchange

between the system and the environment yes what is

allowed is energy exchange yes So

if he is ee Let's say

like this then I have ee

piston yes box like this yes this

is the limit for example then the right and

left are the limits yes then if this is ee

my system yes a system that has mass m yes

then outside this there is an

environment yes then the mass inside

mass control or inside

this closed system must not change whether

it decreases or increases yes So

no mass exchange is allowed

so Here I can write the

mass exchange, no, yes, or yes, there

should be no mass exchange, yes,

if it is in a closed system, yes, but

what is permitted is the exchange of

energy, yes, so here, if it is

an exchange of

energy, yes, this is

permitted, yes. For example, if

the environment has a lower temperature,

yes, like the coffee earlier, yes,

for example, 25 degrees Celsius, then the

closed system has a temperature of 80

degrees C. Celsius then of course there will be an

exchange of energy or energy transfer

from a higher temperature to a

lower temperature but the mass does not change

well it is different from an open system, yes Eh

if the open system is called a

control volume, yes So the volume does

not change, yes if it is

above the mass control, it means the mass

does not change, well in this system there can

be an exchange of mass and energy

between the system and the environment, yes For

example, a nozzle, yes Eh nozzle, eh nozzle,

like that nozzle,

like we want to water the plants, yes we

have a hose then we want to

accelerate the fluid, then we have to

reduce the surface of the hose, yes So more or

less the picture is

like this, yes from one surface, ee, yes

one surface that is

higher, yes then e here there is

a fluid that enters, yes with one

speed V1 then exits with a

speed V2, yes Where v2 is

greater than V1, yes eh

this green one is the limit, yes imaginary limit

Im iminer yes iminer iminer okay, well

then this is also an imaginary limit,

imaginary limit, yes so once again the limit

can be imaginary or indeed, eh one object

that is indeed limit Yes but anyway Eh

this is a control volume yes CV or

control volume yes So there is a

mass exchange because the fluid changes Is it true

or not yes there is water or gas coming in here

then there is also water or gas coming out

yes but what we see is that there is a volume

that does not change yes Therefore,

mass and

energy exchange between the system and the environment may occur yes

Well then there is one more system here

called an isolated system yes if the

system is isolated isolated system it is

not allowed to occur both yes

so mass exchange is not

allowed then

there is also no energy exchange yes this is an

isolated S

yes Well what is important is in

engineering analysis or analysis Yes we have to

define the system clearly

Is it open closed or

isolated yes Well with experience we

can see in ee applications of

thermodynamics When do we determine it

as a closed system When do we

determine it as an open system yes

And we have to know what mass exchange is

like and what energy exchange is also

like yes Next we will

discuss about properties yes properties or what

I usually call quantities yes Well

this property is a characteristic

of a system yes that is

the property yes Well

familiar properties for example there is pressure temperature

volume mass yes maybe I add

there is one more energy yes with the symbol e yes

Well that is eh example of a

property that is often we use it, yes,

this property is divided into two,

yes, so the quantity or here I call

it a property, yes, in thermodynamics,

there are two types, namely the quantity or

property I write here so that it is

not confused, intensive which does not

depend on mass, yes, and extensive which

depends on mass, yes, an example of intensive

is temperature, yes, So if intensive,

the easiest thing for us to know

which quantity is intensive or

extensive,

yes, so intensive does not depend on

mass, does not depend on

mass, yes, for example, if I have one

fluid or one liquid or one gas

that does have a temperature t, yes, it is easy

for us to know whether it is intensive or

extensive if I divide it in two, for example,

I divide the mass in

two, yes, I divide it in two, yes, there is a

first part, there is a second part, yes,

intensive does not depend on mass,

meaning the temperature is certainly the same, yes,

for example, if I have ee coffee

or tea, the temperature is 80, I divide it in two,

both are still 80, right? Is that right?

Both of them don't become 40, right? It would be

very strange if, for example, I have

one ee tea or coffee 80, I share it

with my friend, why is the temperature not divided in two?

Yes in our lives,

another example is pressure, if

I divide it by two, the pressure is the same, yes, and

also the density, yes, or in

Greek symbols, it is R. Well, while

extensive quantities are total mass and

total volume, yes, and of course, if

extensive, for example, I have v, it

is V like that, yes, E. Let's say

how much is 1 liter 2 l, yes, then I divide it by

two, of course, this becomes

1 V. This also becomes 12 V, yes, so that's the

difference between intensive and extensive, yes,

meanwhile, there is something called

extensive property, yes, which is per

unit mass, yes, which is called

specific volume or specific energy, yes,

so E is what is called a

specific quantity, yes, so specific volume

is the total volume per mass and

specific energy is the total energy per

mass, which is usually concluded

with a small e, this is concluded with a

small v, yes, later we will learn about

specific volume and then specific energy

too, eh, when we discuss

things related to

thermodynamics, yes, so that is a

property, yes, once again, there is something called a

system, there are systems that are open,

closed, and also isolated,

then we already know what a

property is, namely the characteristics of a

system, yes, as a constellation, it is actually the

same as humans, yes, humans

have characteristics. Yes,

the characteristics are like this, he is

like this, yes, it is more or less the same

as What are the properties of a

thermodynamic system, okay, let's continue,

yes, eh, there is something called a

state or in English it

is called a state, yes, so the state

or state of a

thermodynamic system is when

the system is in an unchanged condition, yes, it

means that in a certain state, yes, in

a certain state, the properties of a system

can be calculated or measured, yes,

and have a fixed or unchanged value,

yes, that is what is called a

state, yes, so for example, if I have,

once again, I have a box, yes, then

inside it there is a fluid, either gas

or e, Liquid, yes, then

when I measure the mass, 2 kg, then I

measure the

temperature, for example, 20 degrees Celsius,

then the volume, let's say 1 m³, yes,

so I can calculate everything,

yes, and it does not change, this is

called a state, yes, if I

heat it, yes, if I heat it, I

heat it, then of course there will be a

change, yes, if I heat it, there will be a change,

yes, for example, it will be

30 degrees Celsius, yes, the mass and eh,

the volume will also be modified, yes,

it will expands also if it is gas, yes,

the volume will be e, e, the bigger it is,

yes, what is interesting is that this is also a

state if it has indeed

eh, it has not changed, yes, like that, yes,

while there is something called a

state of equilibrium, yes, so there is a state or

condition that is called a state of

equilibrium or in English,

namely equilibrium state, yes, this is

a system that is said to be balanced,

so a system, a system is said to be

balanced if there is no potential that is

unbalanced, yes, so there is a keyword,

namely potential, yes, several

types of equilibrium that must be

balanced, yes, in a system,

if we want to say that it is in a

state of equilibrium, it is

thermal equilibrium, yes, thermal equilibrium, for

example, if I have, for example,

this box, yes, from 20, it rises to 30, right, well,

at that time,

eh, what happens

is, for example, I make it again, yes,

when it starts to be heated, yes, of course, not

everything immediately becomes 30, right,

because this area has started to be 30

degrees, yes, if there is fire below,

for example, there is fire below, yes, yes,

what is below, yes, then

above it, there is still 25, yes, over

here too maybe 20 yes still 20 eh

maybe not 20 yes maybe here 22

here 2 ee 24 yes here 23 and

so on yes Well this is said to be not yet in

thermal equilibrium so thermal equilibrium

is when everything has changed

yes for example I continue to increase

the heat until it reaches

equilibrium yes that means everything is

worth 30 degrees at every point of the

system that we are studying yes

then mechanical equilibrium yes when

there is no force ee or no pressure

yes which indeed ee yes does not change

the pressure yes so the pressure in

each of the areas here yes all of the

areas are all the same yes

So it is not in a state of ee changing or

in a state of non-equilibrium yes

then the phase yes the phase must also be weighed

then chemically it must also be in

equilibrium yes so the chemical composition

should not be ee in a state of change yes

so

for example if there is oxygen gas in here

Yes it is only oxygen gas

yes so it is in a state of equilibrium yes

like that okay Well next we

will discuss the state postulate yes

Well the state postulate ee so if we

maybe before I discuss the

definition of the state postulate yes if I

have a system like this yes I

have a system and I want to know its

characteristics or properties

for example there is P I want to know its v

I want to know its t I want to know

its energy and so on yes then ee Do

I have to know all yes that's

the question yes Can I or not

I only know ee P and I only know

its t Then I can derive

the others yes Well it turns out it can yes only

the question is how much is the minimum quantity

that we have to know to derive the

other quantities so that is the

basis of thinking of the state postulate yes

because in a system there are

many characteristics but how much is the

minimum quantity that I have to

know to derive the

other quantities yes so the state postulate is the

state of a compressed system here there

is

a keyword yes that is compressed

meaning there are no forces yes

other forces such as e force yes what is the

fluid like is moving then there is an

electric force there is a magnetic force that does

cause imbalance that is

the definition of a compressed system yes it

can be described the state of the system

yes by two

mutually independent intensive properties so remember

intensive is a quantity that if I

divide the volume does not change which is mutually

independent Yes that is the requirement for eh

to obtain the state of

eh these two quantities they must be intensive

and mutually independent yes Well two

properties can be said to be independent if

one of the properties is changed the other

is kept constant yes that is an example

I want to know the

e property or quantity of a

system yes we know there is P there is V there is

t e and so on yes well I only

know two but the condition is that both

must be intensive and independent for

example P and t are both

intensive yes and

extensive Okay intensive and extensive

so I can increase the t so the

t is increased while

maintaining the value of p yes that is

the definition of independent so they do not

affect each other directly yes

like that yes For example if I

know P and t then I can decrease the

p yes or the volume by means of yes the

formula that we may have studied

together in high school namely yes the Boile G

lusak formula yes Where pv / t

= constant yes so that is the condition to

obtain the

ee magnitude of a state or

property of a state it must be

At least we must know two properties

that are intensive and independent yes that

is an example of ee from this yes Well

another example is P and specific

volume right volume yes so P

pressure pressure eh sorry It should not be P

and V yes they influence each other yes

So if P and V are not mutually

independent yes but the

other independent ones are ee these are not

mutually independent yes I forgot earlier they are not

mutually

independent yes why yes If I

increase p the v will also change yes

Well I mean additional examples

for intensive and independent ones

are t and speciesfic volume yes this is the

same yes I increase the t the

volume can still be maintained yes yes

For example I have a vessel yes

box or cylinder I heat it yes

but I keep the volume

unchanged so if it is Gas of course

it will start to heat yes but I can

keep the volume constant yes Until

a certain level of course before yes the limit

is damaged yes like that Well that

is the postulate of the state Okay Well

next there is something called a

process and cycle yes process and cycle

so this process is a change of a

system from an equilibrium state to

another equilibrium state for example yes Ee

if I have I will draw it first yes

I have two properties in ee one

or in the XY axis yes for example

this property 1 this property

du yes usually this property ee

volume This property of pressure yes ee

or vice versa yes yes can p can V yes

can p t yes and and and so on yes

Well ee if I draw it here yes

He has for example

P1 P1 then here there is P2 P2 yes

then he

ee processes Yes like this Well for example

curved yes then he can be straight

like this the change can be like this

yes There are many paths yes later we will

learn together it turns out that different paths

or what is called pet or

path Yes it can cause differences in the

characteristics of the system In this case

the work produced yes Well that will be

discussed later in the lecture or video

Next yes like that yes So this

is a state of equilibrium one this is

state 1 then it changes to

state

two yes like that yes So this is an example

yes so ee it is called a

process yes and a series of states Why is it

called a series of states because if

he is in the middle path Here he passes through

every equilibrium point Is that right or not

yes he passes through every ee

equilibrium point here The small ones yes

so that is a series of states that are

passed throughout the process namely path yes

this can be called path one path two

path 3 each of which passes through

processes or sor

small states like that Well then

there is one process that will be the assumption

of our discussion in thermodynamics,

namely the quasi-static process, yes Well this

needs understanding if it's your

first time hearing this, so the

quasi-static or quasi-balance process

is a very

slow process where the system can change

internally so that all

parts of the process in the system

change simultaneously, yes For example,

if I have a piston, let's say

the piston is facing to the right now, yes, it's a

little different, yes, here there is a limit that

can move,

yes, then I press it, yes, so when

I press the particle at the end

here, it will press, yes, the particle

here, maybe it will also

press there, yes, then the value of P, yes,

or the momentum of this particle, yes, or the

right of the wall here, yes,

between the particle and the wall, yes,

they change slowly, yes,

meaning the p changes, yes, then

each of the particles also

adjusts, yes,

so the process is slow,

not fast, so the p changes,

then the volume changes and they do

not overtake each other, yes, so that's the

difference between a fast process

or a fast process quasistatic yes so

every property that changes does not

precede each other so One of the

properties changes yes internally

the system adjusts to the

other properties yes For example I

enlarge this image yes if this is

from this one state to the

second state yes then there is a process

Let's say straight yes so it's easy

this is the process yes Well Is

n't in every process This

direction is probably here yes Isn't in

every process we have

small states yes Let

's say state 1A 1B and so on yes Well in

every state of course

it

has properties too it has P P and

t also here is also the same it has P

P and t also yes well every Quantity

changes yes for example yes this p p accent this

P accent accent accent Dou accent Dou accent

yes it changes yes but they do not precede each other

yes Nothing is faster

than the other yes So when

the pressure changes the volume also

changes the t also t also

changes yes Well this process is an

assumptive process yes or assumption yes

which in real life eh

we don't encounter much but in terms of

eh static brush process that is in

thermodynamics we use the

assumptions, yes, for what to calculate

maximum efficiency, we will

learn later in the next chapters, yes,

for example, some types of processes that

we may have learned

in high school, there is something called

isothermal, namely constant t, isohoric, namely

constant v, yes, there is something

called isobaric or

constant p, yes, or adiabatic, yes, So there

is no exchange or no change

in heat, yes, So there is no heat

flowing, yes, like that, yes, so it

is an isothermal, isohoric,

isobaric and

adiabatic process, yes, okay, yes, like that, yes, then

this is what we will probably

learn throughout this course, yes,

then what is related to the

process is a cycle, yes, a cycle

is a system that goes

through a series of

processes, yes, whose condition returns to its

original state, yes, So if I make it

again here, the

x-axis is usually P, the y-axis is

usually P, yes, Uh, pressure and

volume, yes, for example, the first state,

then it moves to the second state, then it moves

to the third state, yes,

then it moves again, back

to the state that was first Yes, this is

called a cycle, yes, this is the

first process, then it tilts a little bit, the

second process, yes, then it comes back

here, up Sorry, we're back

to it, I'll make a new line, yes,

like this, yes, So this is what is called a

cycle, ee, cycle, cycle, yes, so one, second, two, third,

three,

back to one, yes, this is called a

cycle, yes, later we will

also learn a lot of thermodynamic cycles,

yes, which are indeed the characteristics of

several applications or engines that

we will learn, such as the

steam engine cycle, then the ee, ee,

refrigeration cycle, yes, those are examples of

cycles that we will learn

later, okay, now, ee, this is the

last part, namely the zeroth law of

thermodynamics, yes, so the Zeroth Law of

Thermodynamics is interesting, yes, why is

there a zeroth law? Yes, because there is the

first law, then there is the second law that

we discussed in the

previous slide, yes, why is there a

zeroth law, it turns out that this zeroth law was

discovered, maybe not discovered, yes,

formulated by scientists, yes,

long after the first law and the

second law, yes, so

ee, so far, yes, even em, because

far away, yes, it's been 50 years, yes,

So almost half a century, the first law

already exists, the second law already exists, eh,

it turns out there is a zeroth law which is

considered much more fundamental

than law 1 and law 2, that's why it's

called the zeroth law Yes, like

that Well, this zeroth law speaks or

has a definition or has a formulation, ee

ee, so if there are two objects that are in

thermal equilibrium with a third object,

then the two objects are in

thermal equilibrium, yes, for example, ee, if I

have one object, for example, a box

like this, then I have another object, yes,

Okay, I have another one, for example, this B,

this B,

yes, then this one is a, yes,

then a and b are in equilibrium with

object C, yes, weigh it with object C, yes,

I make

another box, yes, more or less like this, yes, this

is C, yes, So if

a If A and C are in

thermal equilibrium, it means the temperature is the same, right,

then B and C are in thermal equilibrium

too, yes,

then a and b are in

thermal equilibrium Well, maybe you think up to

here, yes, Oh yes, ten That's all If A

and C are the same temperature or

thermal equilibrium B and C are thermal equilibrium well

obviously A and thermal equilibrium base Well

why should it be formulated Well that's the

importance there is one ee law yes there is

one phenomenon that is more

fundamental yes which indeed It

seems natural yes

but they call it the

people call it the law of Keol

yes Well the concept of temperature is actually

related to the law of Keol yes

in its application the concept of temperature or

temperature measuring instrument is two objects

in a state of thermal equilibrium if

both objects have the

same temperature yes maybe you also think

here yes yes yes yes yes if I have

two objects eh thermal equilibrium both

have the same temperature yes but that

is the first way of thinking that

humans can measure temperature

using one tool yes So if I

have one ee object yes then I

dip the thermometer yes then

this thermometer will start measuring yes with

its scale t for example in degrees

Celsius yes then I can know

the temperature of eh this substance yes or

system

by looking at the temperature of the

thermometer yes And they are made or yes

Legally Oh this thermodynamics ee the

thermometer has the

same temperature as the system yes

Therefore the temperature measurement that

we have been doing is

one of the applications of ee the Zeroth Law of

Thermodynamics yes yes even though this

looks ee simple yes but it must be

understood that ee this is

one of the ee laws that is indeed important Yes

because it is so important ee was discovered long

after law 1 and law 2 so it

is called the zeroth law of thermodynamics yes

okay that's all for today's lecture ee

in this video I mean and EE

Hopefully all my friends or anyone

who watches this video can also

understand the basic concepts of vocabulary and also

many terms in thermodynamics Okay see

you in lecture or in the next video