Thermodynamics

tolman law beginner

Tolman Law in a Nutshell

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The Tolman law describes how the temperature in a fixed gravitational field depends on the position (see https://arxiv.org/abs/1803.04106 for a pedagogic…
perpetual motion machines

Why We Don’t Discuss Perpetual Motion Machines (PMM)

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Authorship Authorship Contributions From Anorlunda Introduction You may want to believe the article you read, or the video you saw, or you may be very…
What is Entropy

What Thermodynamics and Entropy Means

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Introduction The student of thermodynamics, as they consider pistons and ideal gasses and such, often begin to grasp the nature of entropy only to find…
Star Equations

Equations of State for Photon Gas and Relativistic Electron Gas

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This Insight develops equations of state that are useful in calculations about cosmology and about the insides of stars. The first calculation is for a…
statmech2

Learn Statistical Mechanics: The Ideal Gas

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Read Part 1: Equilibrium Systems The Ideal Gas: Boltzmann's Approach (The Microcanonical Ensemble) Consider a monatomic gas of ##N## non-interacting…
statmech1

Learn Statistical Mechanics: Equilibrium Systems

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This is the first of a multi-part series of articles intended to give a concise overview of statistical mechanics and some of its applications. These articles…
SpectralParadox

Exploring the Spectral Paradox in Physics

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In terms of wavelength, peak solar radiation occurs at about 500 nm.  Interestingly, this is well within the range of human vision.  When solar radiation…
entropy

How to Determine the Change in Entropy

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How do you determine the change in entropy for a closed system that is subjected to an irreversible process?Here are some typical questions we get…
islingmodel

High Temperature and Low Duality for the Ising Model on an Infinite Regular Tree

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Today I felt like sharing a computation that I thought was interesting. I'm sure I'm not the first to explore the Ising-Ising duality in this context,…
greenhouse

Frequently Made Errors in Climate Science – The Greenhouse Effect

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1.What is meant by "The Greenhouse Effect"? Many gases, such as H2O, CO2, CH4, are transparent to visible light but absorb and emit parts of the infrared…
heat

What Is Heat? Definition in Thermodynamics Explained

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One of the most frustrating misconceptions in thermodynamics centers on the actual definition of heat. Many science and engineering students refer to a…
gas compression

Reversible vs Irreversible Gas Compression and Expansion Work

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Introduction In learning Thermodynamics, one of the difficult concepts that many students struggle with is the difference between reversible and irreversible…
heat errors

Frequently Made Errors in Heat: Elementary Level

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1. Heat, Work, Internal Energy, and Kinetic Energy "If heat is the motion of molecules, why isn't it Kinetic Energy?"In everyday use, we may think…
negative temperature

Negative Absolute Temperatures: Explanation & Examples

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It's a famous result in thermodynamics that you cannot reach absolute zero no matter how hard you try. Given the definition of absolute zero, it is also…
Thermodynamics

Understanding the Second Law of Thermodynamics Clearly

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Introduction The second law of thermodynamics and the associated concept of entropy have been sources of confusion for thermodynamics students for centuries.…