Lecture Notes: Introduction to Thermodynamics

Overview

• Interactive lecture using demonstrations and the book "Statistical Physics for Babies" by Chris Ferry.
• Focus on basic principles of thermodynamics through simple examples and demonstrations. ##jwowkwo z

Movement and Distribution

• Ball Movement Example: Illustrates how energy added to objects causes movement and distribution.
  • Six balls in a divided space can be on the left or right.
  • Movement shows randomness in distribution—unlikely to find all on one side.
• Scientific Explanation: Non-interacting gas molecules in a box.
  • Removing a partition leads to spontaneous distribution.
  • Key thermodynamics concept: Spontaneity increases system disorder (entropy).

Entropy and Probability

• Entropy measures the number of different combinations or states.
  • States with more combinations are more likely (higher entropy).
• Example with Colored Balls: Shows probability of different distributions.
  • Most likely to find even distribution due to more possible configurations.
  • Entropy increases with more disorder in a system.

Thermodynamic Processes

Endothermic and Exothermic Reactions

• Endothermic Process: Ammonium nitrate dissolving in water.

  • Absorbs heat, increasing system energy and entropy.
  • Demonstrated with cold packs: Reaction goes right, absorbing heat.

• Exothermic Process: Crystallization of sodium acetate from solution.

  • Releases heat, decreasing system energy and entropy.
  • Demonstrated with hot packs: Reaction goes right, releasing heat.

Balance of Energy and Entropy

• Thermodynamics balances entropy (disorder) and energy (enthalpy).
• Nature's tendency to increase entropy vs. decrease energy.
• Understanding balance is crucial for predicting reaction outcomes.

Applications: Phase Diagrams

• Phase Diagrams: Visual tools to understand material state under different conditions.
  • Water phase diagram: Shows states based on temperature and pressure.
  • Binary phase diagram: Composition vs. temperature (e.g., copper-zinc system).
  • Ternary and other specialized diagrams for various applications.
• CALPHAD (CALculation of PHAse Diagrams): Computational tools for phase diagram calculation.

Course Goals

• Learn to calculate and interpret phase diagrams.
• Understand the theoretical framework for equilibrium and phase balance.
• Practical application via software tools like Thermo-Calc.

Final Thoughts

• Thermodynamics is complex but fundamental.
• Encouragement to embrace the challenge as understanding deepens over time.