Thermodynamics involves energy transfers and changes in systems and their environments. It explains properties of matter at bulk and atomic scales. Historically, thermodynamics developed alongside atomic theory. It addresses questions like how refrigerators cool and what occurs in power plants. Thermal phenomena depend on the substance involved - gases expand more than liquids or solids with heat. Careful definitions of temperature, heat, and internal energy are needed to describe thermal interactions.

1. THERMODYNAMICS
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2. • Thermodynamics
• System
• Surrounding
• Boundary
• Weight vs Mass
• Force
• Heat
• Energy
• Kinetic energy
• Internal energy
• Thermal phenomena
• Temperature
• Thermal contact
• Thermal equilibrium
• Zeroth Law of
Thermodynamics
• Thermometers
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3. Science of
It is difficult to give a
precise definition of
energy but,
Energy can be
proved as the ability
to cause the change.
(Greek word)
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THERMODYNAMICS
•Thermodynamics involves situations in which the temperature or state of a
system changes due to energy transfers.
•Thermodynamics is very successful in explaining the bulk properties of matter.
•Also successful in explaining the correlation between these properties and the
mechanics of atoms and molecules.
•Historically, the development of thermodynamics paralleled the development of
atomic theory.
•Thermodynamics also addresses practical questions:
• How a refrigerator is able to cool its contents
• What types of transformations occur in a power plant
• What happens to the kinetic energy of an object as it comes to a rest

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6. TYPES OF SYSTEMS
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9. Forces can be described as a push or
pull on an object.
They can be due to phenomena such
as gravity, magnetism, or anything that
might cause a mass to accelerate.
In physics, a force is any interaction
that, when unopposed, will change
the motion of an object.
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10. Heat is a form of energy that can be converted into work. Amount of energy is
expressed in units of work.
 It is expressed in joules, foot-pounds, kilowatt-hours, or calories.
 Heat as a form of energy can be converted to other forms of energy.
Heat is the amount of energy flowing from one body to another
spontaneously due to their temperature difference.
HEAT
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11. • There are different forms of energy on this planet.
• Energy is considered a quantitative property which can be transferred from
an object in order for it to perform work.
the fundamental form of living for all living beings
Energy is the ability to do work
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16. we consider why an important factor,
when we are dealing with thermal
phenomena, is the particular
substance we are investigating.
For example, gases expand appreciably when
heated, whereas liquids and solids expand only
slightly. 16
To describe thermal phenomena, careful definitions are needed:
• Temperature
• Heat
• Internal energy
Thermal phenomena involving particular substances is important.

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TEMPERATURE
We associate the concept of temperature with how hot or cold an
object feels.
Our senses provide us with a qualitative indication of temperature.
Our senses are unreliable for this purpose.
We need a reliable and reproducible method for measuring the relative
hotness or coldness of objects.
• We need a technical definition of temperature.

18. thermal contact and thermal equilibrium.
Thermal contact
Thermal equilibrium
we assume that two objects are in
thermal contact with each other if
energy can be exchanged between
them by these processes due to a
temperature difference
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19. Thermal equilibrium is a situation in which ‘two objects would not
exchange energy by heat or electromagnetic radiation if they were
placed in thermal contact.’
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Thermal Contact and Thermal Equilibrium
Two objects are in thermal contact with each other if energy can be
exchanged between them.
• The exchanges we will focus on will be in the form of heat or electromagnetic
radiation.
The energy is exchanged due to a temperature difference.
Thermal equilibrium is a situation in which two objects would not
exchange energy by heat or electromagnetic radiation if they were
placed in thermal contact.
• The thermal contact does not have to also be physical contact.

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If objects A and B
are separately in
thermal equilibrium
with a third object C,
then A and B are in
thermal equilibrium
with each other.
• Let object C be
the thermometer
• Since they are in
thermal
equilibrium with
each other, there
is no energy
exchanged among
them.
 Object C (thermometer) is placed in contact with A until they achieve
thermal equilibrium.
• The reading on C is recorded.
 Object C is then placed in contact with object B until they achieve
thermal equilibrium.
• The reading on C is recorded again.
 If the two readings are the same, we can conclude that A and B are in
thermal equilibrium with each other.

22. We can think of temperature as the property that
determines whether an object is in thermal equilibrium with
other objects.
Two objects in thermal equilibrium with each other are at
the same temperature.
Conversely, if two objects have different temperatures,
then they are not in thermal equilibrium with each other.
Temperature is something that determines whether or not
energy will transfer between two objects in thermal contact.
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