PHYS 334 MACROSCOPIC PHENOMENA AND
THERMODYNAMICS
Tariq H. Gilani Room: 236 Ph. X 7449 E-mail: [email protected] www.sites.millersville.edu/tgilani OFFICE HOURS Mon. 10 to 12 Wed. 2 to 4 Thur. 11 to 12
PLEASE TURN OFF YOUR CELL PHONS!
PresenterPresentation NotesStudents’ introduction
mailto:[email protected]://www.sites.millersville.edu/tgilani
SYLLABUS Text: Schroeder, “Thermal Physics”, Addison Wesley, 1999. Suggested: Gould and Tobochnik, “Statistical and Thermal Physics With Computer Applications” , Princeton University Press, 2010.
Method: Lecture, Discussions, Problems, Simulations.
Assessment: Final grades will be derived from Homework Assignments 15% Three Midterm Exams 20% each Comprehensive Final 25%
All exams will be open book: only textbooks
Assignments: Late assignments maybe accepted for lesser credit or may not be accepted at all. Exam-I on Fundamentals Ch. 1, Ch. 2 and Ch 3 Exam –II on Thermodynamics Ch. 4 and Ch. 5 Exam-III on Statistical Mechanics Ch. 6 and Ch. 7 Grading 93-100% A 90-92.9% A- 87-89.9% B+ 83-86.9% B 80-82.9% B- 77-79.9% C+ 70-76.9% C 60-69.9% C- 55-59.9% D+ 50-54.9% D
MACROSCOPIC SYSTEM
We will explore the fundamental difference between microscopic and macroscopic system
System of many constituents For example: many electrons many atoms many photons many dipoles
Familiar systems Less familiar systems Superconductors Brains Stock markets Neutron stars
Air in this room A cup of water Gases, liquids, solids, polymers
Air in the room
Do we care about the trajectory of a particular air molecule? Will this knowledge be helpful in understanding the air properties? In this case, we should ask: How does the pressure of the air depend on temperature and volume of this room? General questions about a macro system? How does a refrigerator work? Why are the properties of water different from steam and ice? How and why the properties of a sheet of iron different from iron atom? Why heat flows from high temperature to low? Why not opposite?
Single air molecule is microscopic system
Air in the room is macroscopic system
Groups of questions about macro systems
Macroscopic properties For example, thermal, magnetic, elastic properties, etc. Relation of macro system to its individual constituents Macroscopic behavior starting from atomic nature of the matter. (Statistical Mechanics) Time dependence of macroscopic phenomena For example, turbulent flow, hurricanes, etc.
Focus will be on Thermodynamics
We will discuss on 1st and 2nd group Although statistical mechanics will be introductory only
A CUP OF A HOT WATER IN A LARGE COLD ROOM
Important properties associated with this macro system Temperature is important: Hot water cools … temp becomes equal to room temp. Time arrow (direction of time): Does ever a cup of water at room temperature gets hotter? WHY NOT?
No direction of time at microscopic level
Newton 2nd law for a single particle => motion of the particle is time-reversal invariant.
No one has ever observed a ball at rest spontaneously begin to bounce and bounce higher and higher.
Eq. of motion, energy conservation, etc. can not stop this phenomena for a microscopic system
Two cups of similar water Motion of water particles in both cups will be very different. (Microscopic properties) The observable properties (temp, pressure, etc.) of the water in each
cup are indistinguishable. (Macroscopic properties)
The behavior of a macro system is very different from that of its single particle, although both are related.
Examples of the properties of a macroscopic system: Temperature, energy, pressure, volume, entropy, etc.
Familiar More complicated Thermal conductivity of solid, viscosity of a fluid, elasticity, magnetism, strength of a material, etc.
How these macro properties are related to: • Each other? • The properties of individual constituents?
What is meaning of temperature, entropy, etc.?
WORK AND QUALITY OF ENERGY
Hot objects cool. Bouncing balls come to rest.
But cool objects don’t spontaneously become hot.
Stationary balls don’t spontaneously begin to bounce. Although total energy is conserved in
these processes.
The distribution of energy changes in an irreversible manner
Converting energy into heating Wood/coal open flam Heating Rubbing hands Heating Easy and no theoretical limit on efficiency
Can you convert heat back into wood/coal?
Converting stored energy in useful work? Discovery lead to industrial revolution
Automobile Engine: Gasoline KE of automobile
Energy associated with many degrees of freedom
Energy associated with fewer degrees of freedom
Difficult process
Energy associated with many degrees of freedom
Energy associated with fewer degrees of freedom Easy process
Some forms of stored energy are more useful than the other
Can we convert stored energy into useful work with 100% efficiency?
Can we extract energy stored in atmosphere to run a power plant?
Leads us to 2nd Law of Thermodynamics
Next class we will talk about Fundamentals in Thermodynamics.
SIMULATIONS
www.compadre.org/stp OR http://press.princeton.edu/titles/9375/html Download or run as an applet. Java 1.5+ is required.
http://www.compadre.org/stphttp://press.princeton.edu/titles/9375/html
We will use calculus regularly throughout this course. Please refresh your Mathematics For your own practice. Solve the problems distributed
Assignment (Mathematics Refresher)
No class on Friday Jan 21
PHYS 334�Macroscopic Phenomena and ThermodynamicsSyllabusSlide Number 3Macroscopic SystemAir in the roomGroups of questions about macro systemsA cup of a hot water in a large cold roomTwo cups of similar waterWork and quality of energySome forms of stored energy are more useful than the otherSimulationsSlide Number 12
