THERMODYNAMICS AND ITS LAWS

1. In the name of Allah,
the most Gracious, the
most Merciful.

2. Topic
Thermodynamics and
its Laws

3. Learning outcomes:
• Thermodynamics
• Introduction to
thermodynamics
• Branches of
thermodynamics
• Thermodynamics
processes
• Laws of
thermodynamics
• Summary

4. • What is
thermodynamics?1
• What’s about
thermodynamics?2
• Laws of
thermodynamics?3
Today’s Overview

5. Thermodynamics is a branch
of physics which deals with the
study of relationship between
heat and other forms of
energy.
In particular it describes how
thermal energy is converted to
and from other forms of
energy and how it affects
matter.

6. Around 1850 Rudolf
Clausius and William
Thomson (Kelvin) stated both the
First Law - that total energy is
conserved - and the Second Law of
Thermodynamics. The Second Law
was originally formulated in terms
of the fact that heat does not
spontaneously flow from a colder
body to a hotter. Then in such a way
thermodynamics was introduced.
• Who introduced thermodynamics?

7. Rudolf Clausius William Thomson

8. • Introduction
Thermodynamics is concerned
with many states and processes
but some of the main are:
• Heat
• temperature
• Thermal energy
• Specific heat
• Thermal conductivity
• Heat transfer
• Entropy
• Internal energy

10. 1. Heat
• Thermodynamics, then, is concerned with several
properties of matter; foremost among these is heat. Heat
is energy transferred between substances or systems due
to a temperature difference between them, according to
Energy Education. As a form of energy, heat is conserved,
i.e., it cannot be created or destroyed. It can, however, be
transferred from one place to another. Heat can also be
converted to and from other forms of energy. For
example, a steam turbine can convert heat to kinetic
energy to run a generator that converts kinetic energy to
electrical energy. A light bulb can convert this electrical
energy to electromagnetic radiation (light), which, when
absorbed by a surface, is converted back into heat.

11. 2. Temperature
• Temperature (sometimes called
thermodynamic temperature) is a measure of
the average kinetic energy of the particles in a
system. Adding heat to a system causes
its temperature to rise.
• Several scales and units exist for measuring
temperature, the most common
beingCelsius (denoted °C; formerly called
centigrade), Fahrenheit (denoted °F), and,
especially in science, Kelvin (denoted K).

12. 3. Thermal Energy
• Thermal energy is the energy that comes from heat. This
heat is generated by the movement of tiny particles within
an object. The faster these particles move, the more heat is
generated. Thermal energy is the energy that comes from
heat. This heat is generated by the movement of tiny
particles within an object. The faster these particles move,
the more heat is generated. Thermal energy results in
something having an internal temperature, and that
temperature can be measured - for example, in degrees
Celsius or Fahrenheit on a thermometer. The faster the
particles move within an object or system, the higher the
temperature that is recorded.

13. 4. Specific Heat
• Specific Heat is the amount of heat required to
change a unit mass of a substance by one degree in
temperature. The heat supplied to a mass can be
expressed as
dQ = m c dt (1)
where
dQ = heat supplied (kJ, Btu)
m = unit mass (kg, lb)
c = specific heat (kJ/kg oC, kJ/kg oK, Btu/lb oF)
dt = temperature change (K, oC, oF)

14. 5. Thermal
Conductivity
• Thermal conductivity refers to the amount/speed of heat
transmitted through a material. Heat transfer occurs at a higher
rate across materials of high thermal conductivity than those of
low thermal conductivity. Materials of high thermal
conductivity are widely used in heat sink applications and
materials of low thermal conductivity are used as thermal
insulation.Thermal conductivity of materials is temperature
dependent. The reciprocal of thermal conductivity is called
thermal resistivity. Metals with high thermal conductivity, e.g.
copper, exhibit high electrical conductivity. The heat generated in
high thermal conductivity materials is rapidly conducted away
from the region of the weld. For metallic materials, the electrical
andthermal conductivity correlate positively, i.e. materials with
high electrical conductivity (low electrical resistance) exhibit
high thermal conductivity.

15. 6. Heat Transfer
• Heat transfer by conduction and
convection. Heat is thermal energy. It can
be transferred from one place to another by
conduction, convection and radiation.
Conduction and convection involve particles,
but radiation involves electromagnetic
waves.

16. 7. Entropy
• A measure of the unavailable energy in a
closed thermodynamic system that is also
usually considered to be a measure of the
system's disorder, that is a property of the
system's state, and that varies directly with
any reversible change in heat in the system
and inversely with the temperature of the
system; broadly : the degree of disorder or
uncertainty in a system

17. 8. Internal
Energy
• Internal energy is defined as
the energy associated with the random,
disordered motion of molecules. It is
separated in scale from the macroscopic
orderedenergy associated with moving
objects; it refers to the invisible
microscopic energy on the atomic and
molecular scale.

18. LAWS
OF
THERMODYNAMICS

19. • Zeroth law1
• First law of
thermodynamics2
• Second law of
thermodynamics3
Laws of thermodynamics
• Third law of
thermodynamics4

21. • Zeroth law
• The zeroth law of thermodynamics states that if
twothermodynamic systems are each in thermal
equilibrium with a third, then they are in
thermal equilibrium with each other.
• It is called the "zeroth" law because it came to
light after the first and second laws of
thermodynamics had already been established
and named, but was considered more
fundamental and thus was given a lower
number — zero.

22. • First law of
thermodynamics
• The First Law of Thermodynamics states that heat is a
form of energy, and thermodynamic processes are
therefore subject to the principle of conservation of
energy. This means that heat energy cannot be
created or destroyed. It can, however, be transferred
from one location to another and converted to and
from other forms of energy. For example; A hot gas,
when confined in a chamber, exerts pressure on a
piston, causing it to move downward. The movement
can be harnessed to do work equal to the total force
applied to the top of the piston times the distance
that the piston moves.

23. • Second Law of
Thermodynamics
• The second law of thermodynamics states that
the total entropy of an isolated system can only
increase over time. It can remain constant in
ideal cases where the system is in a steady state
(equilibrium) or undergoing a reversible process.
The second law of thermodynamics says that
when energy changes from one form to another
form, or matter moves freely, entropy (disorder)
increases. Differences in temperature, pressure,
and density tend to even out horizontally after a
while.

24. • Third law of
thermodynamics
• The third law of thermodynamics is
sometimes stated as follows, regarding the
properties of systems in equilibrium at
absolute zero temperature: The entropy of a
perfect crystal at absolute zero is exactly
equal to zero.
• At 0 K, entropy stops. This is known as
absolute zero, and in theory, this is not
possible.