Heat, entropy, and why time moves forward.
Energy flows one way. Entropy only grows. Out of these two facts come steam engines, refrigerators, the arrow of time, and the heat death of the universe. Thermodynamics is the part of physics that feels most like philosophy.
MODULE 1 · TEMPERATURE & HEAT
WHAT IS TEMPERATURE?
Before thermometers, science couldn't even state the question.
HEAT AND THE CALORIC THEORY
How a cannon-boring contract proved heat is motion, not fluid.
HEAT CAPACITY AND CALORIMETRY
Why a pound of water and a pound of mercury refuse to warm alike.
PHASE CHANGES AND LATENT HEAT
Where the energy hides while the thermometer stands still.
MODULE 2 · THE FIRST LAW
INTERNAL ENERGY AND THE FIRST LAW
Energy is conserved; heat and work are two ways to spend it.
WORK, PV DIAGRAMS, AND REVERSIBILITY
When Clapeyron drew Carnot's prose, engineers could read thermodynamics.
ISOTHERMAL AND ADIABATIC PROCESSES
Why a bicycle pump scalds when fast and barely warms when slow.
MODULE 3 · THE SECOND LAW
HEAT ENGINES AND SADI CARNOT
The deepest book in thermodynamics, written by a man who died thinking he'd failed.
THE SECOND LAW
The energy of the universe is constant; its entropy tends to a maximum.
ENTROPY AS HEAT OVER TEMPERATURE
The quantity that holds steady on reversible trips and grows on every other one.
MODULE 4 · ENTROPY & THE ARROW OF TIME
MICROSTATES AND MACROSTATES
You never see ten heads — there's only one way to do it and a hundred others not to.
BOLTZMANN'S FORMULA: S = k log W
The equation they carved on his tombstone.
THE ARROW OF TIME
Why a smashing glass never reassembles, though no law of motion forbids it.
MODULE 5 · KINETIC THEORY OF GASES
THE IDEAL GAS LAW
Three centuries of laboratory arithmetic, collapsed into one line.
PRESSURE FROM MOLECULAR COLLISIONS
Temperature, it turns out, is just kinetic energy per molecule.
THE MAXWELL-BOLTZMANN DISTRIBUTION
The first probability distribution in the history of physics.
EQUIPARTITION AND DEGREES OF FREEDOM
One theorem for every heat capacity — and three cracks that let the quantum in.
BROWNIAN MOTION
The jitter of pollen grains that finally made atoms undeniable.
MODULE 6 · STATISTICAL MECHANICS
THE PARTITION FUNCTION
One sum from which all of thermodynamics falls out by differentiation.
FREE ENERGIES AND MAXWELL'S DEMON
The demon was never free: erasing a memory costs entropy.
FLUCTUATIONS AND DISSIPATION
The hiss in every amplifier is the second law made audible.