Thermodynamics

"Thermodynamics" comes from the greek words "therme" which means heat and "dynamikos" which means force,power. So "Thermodynamics" is essentially the study of forces due to heat or heat due to forces. It deals with the conversion of energies in terms of heat and mechanical work and their relationship with properties of the system. The field of engineering science, which deals with the applications of thermodynamics and its laws to work producing and work absorbing devices, in order to understand their functions and improve their performance, is known as Thermal Engineering.

An understanding of the common terminology would be very useful before going further.

Terminology:

System: The region of interest for the purpose study. It is assumed that this region can be considered separated or weakly-interacting with the rest of the Universe.

Boundary: An imaginary line that encompasses the region of interest. It should be noted that boundary effects are neglected in Thermodynamics. This can be justified by comparing the number of molecules in a volume of condensed matter to the number of molecules near the surface.

Equilibrium: The state where heat flow into and out of the system are equal. In the case of static equilibrium, no change in temperature occurs. During dynamic equilibrium, more heat flows into the system at certain times, and out at others, so that the temperature does change, but, on average, still stays the same.

Microscopic and Macroscopic Descriptions: The state of a system can be specified in two key ways. The first is with a microscopic description, where the position and momentum of every particle is specified. The other is a macroscopic description, where a relatively few thermodynamic variables (i.e. temperature, pressure, volume) are specified.

Heat: Energy transfer due to temperature difference.

Work: Energy transfer due to movement.

Temperature: Temperature is a property which measures the degree of hotness or coldness of body. This is due to molecular vibration.

Principal laws of Thermodynamics

• Zeroeth law of thermodynamics states that if two objects are each in thermal equilibrium with a third, then they are also in thermal equilibrium with each other.
• The first law of thermodynamics states that energy can be neither created nor destroyed.
• The second law of thermodynamics states that dq=tds.
• The third law of thermodynamics states that at absolute zero (the lowest possible temperature), there is no molecular movement.

Introduction to Thermodynamics

Now let's see the chapters we will cover in what can be called an "Introduction to Thermodynamics" as a University course. Here we are:

• Thermal Properties Of Matter
• Temperature And Heat
• The First Law Of Thermodynamics
• The Second Law of Thermodynamics

Wikibooks

• Engineering Thermodynamics