Statistical Thermodynamics

Statistical thermodynamics Collage: It seeks to address how are the microscopic properties of individual molecules related to the properties of a sample which contains 10²³ molecules, or – more macroscopic world. We can think of statistical thermodynamics as a process of model building In the macroscopic world we deal with quantities such as internal energy, enthalpy, entropy, heat capacities, and so on. In the microscopic world we deal with wave functions, particle momenta, kinetic and potential energies, energy levels, and so on. The usual theoretical framework of the microscopic world is quantum mechanics and the fundamental equations are Schrödinger's equations .

The point of contact between the two disciplines is taken to be the function for Entropy S which is a function of the thermodynamic variables S=S(U, V, N) etc, with U being internal energy, V volume.

Statistical thermodynamics involves probabilities, therefore collage shows graphs of distribution of energies of particles present in system. The approach to the foundations of statistical thermodynamic th is sometimes referred to as “Boltzmannian”, collage includes photo of physicist Ludwig Boltzmann , representing a development of ideas originally put forward by Boltzmann—postulates a probability distribution over a set of possible initial conditions for the universe

Collage shows that

1. Statistical thermodynamics is based on the fundamental assumption that all possible configurations of a given system, which satisfy the given boundary conditions such as temperature, volume and number of particles, are equally likely to occur.

2. The overall system will therefore be in the statistically most probable configuration. The entropy of a system S is defined as the logarithm of the number of possible configurations multiplied with Boltzmann’s constant S=k ln W.. The totality of these microstates, and their associated energy, is determined from a partition function..

Message of Collage:The theory of the relations between various macroscopic observables such as temperature, volume, pressure, magnetization and polarization of a system is called thermodynamics.Statistical Thermodynamics is the theory of the physical behaviour of macroscopic systems starting from a knowledge of the microscopic forces between the constituent particles. Thermodynamics is concerned about heat and direction of heat flow,statistical thermodynamics gives properties of heat like heat capacity in terms of structure of matter.

History of Atom Through Postage Stamps

Commentary:The present educational collage shows the history of atoms through postage stams.German physicist named Max Planck (1858-1947) , proposed that energy behaved according to the equation E = hν , indicated birth of the quantum era. Einstein was able to use the idea of quantized energy to Photoelectric Effect .Max Planck stamps and Einstein stamp shown in collage was issued in their honor when they received their Nobel Prize for their findings. Ernest Rutherford, gave basic idea of an atom and advanced it with his “planetary model”. Bohr suggested that the electrons circling atoms traveled in “well-defined circular orbits”. The stamp honoring Bohr shows his signature. Louis de Broglie had proposed a theory whereby any particle exhibits wavelike properties no matter what its size. The de Broglie stamp shows a wave for his de Broglie wavelengths overlaid with amplitude graphs showing where the particle is likely to be found. Nobel Prize winner of Physics (1932) Werner Heisenberg (1901-1976) put forward one of the first ideas of quantum mechanics, the Uncertainty Principle. This collage includes stamp of Werner Heisenberg and illustrates a molecular structure honoring his theory helping to explain the structure of atoms and molecules.

Austria, Erwin Schrödinger (1887-1961)nobel prize winner(1933), model replaced Bohr’s “Well-Defined Circular Orbits” with the idea of an orbital. This became Schrödinger’s wave equation. The stamp for Schrödinger shows wave functions for two different electron orbitals representing the electron density predicted by his wave equation..

Message of collage :Importance of postage stamps in scientific development cannot be denied. From the time of the ancient Greeks until today, the visual concept of the atom is obscure, yet the mathematical concepts have grown stronger. The present collage shows development of models of atoms through postage stamps. It starts with findings of Max Planck and ends at Schrödinger’s wave equation.