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50 free Thermodynamics trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This thermodynamics trivia quiz runs from the basics every physics student meets to the strange corners of the subject. It starts with the four laws, absolute zero and the Kelvin scale, then moves through the history: Guericke's vacuum pump, Papin's steam digester, Joseph Black and James Watt in Glasgow, Sadi Carnot's single book, Clausius coining entropy and Boltzmann giving it a statistical meaning. From there it heads into the ideas that make the field fun to argue about: Maxwell's demon and the physicists who tried to exorcise it, the heat death of the universe, perpetual motion machines from a 12th-century wheel to a 17th-century bishop, Gibbs free energy and the arrow of time. The opening questions suit anyone who remembers high-school science; the closing ones reward readers who know who named the demon and how cold a lab has ever got. Every answer was checked against encyclopaedia entries before publishing.
30 of 50 questions with answers and explanations. Play the quiz
Q 01How many laws of thermodynamics are there?
Four
The zeroth law was added after the other three were already numbered, because renumbering them was impractical.
Q 02Which way does heat never flow on its own, according to a classic statement of the laws?
From a colder body to a hotter one
That everyday observation is one traditional way of stating the second law.
Q 03Which law of thermodynamics expresses the conservation of energy?
First law
Energy can be transformed from one form to another but cannot be created or destroyed.
Q 04What is absolute zero on the Celsius scale?
−273.15 °C
The same point is −459.67 °F and 0 on both the Kelvin and Rankine scales.
Q 05Which temperature scale is defined with absolute zero as 0?
Kelvin
The Rankine scale also starts at absolute zero but uses Fahrenheit-sized degrees.
Q 06Who is known as the 'father of thermodynamics'?
Sadi Carnot
His 1824 Reflections on the Motive Power of Fire was the only book he ever published.
Q 07Which physicist coined the word 'entropy' in 1865?
Rudolf Clausius
He chose a Greek word for transformation and deliberately made it sound like 'energy'.
Q 08The word 'entropy' was coined from a Greek word meaning what?
Transformation
Clausius first called it Verwandlungsinhalt, transformation-content, before settling on the Greek-derived name.
Q 09Which practical problem drove the early development of thermodynamics?
Steam engines
Carnot's 1824 analysis of engines was later built upon by Kelvin and Clausius.
Q 10Who built the world's first vacuum pump in 1650?
Otto von Guericke
He wanted to disprove Aristotle's claim that nature abhors a vacuum, and did so with his Magdeburg hemispheres.
Q 11Boyle's Law says which two gas properties are inversely proportional?
Pressure and volume
Boyle and Hooke noticed the correlation using an air pump built in 1656.
Q 12Denis Papin's 1679 'steam digester' was essentially an early what?
Pressure cooker
Watching its release valve bob up and down gave him the idea of a piston-and-cylinder engine.
Q 13Who developed the concepts of heat capacity and latent heat at the University of Glasgow?
Joseph Black
James Watt was the university's instrument maker at the time and experimented alongside him.
Q 21What is held constant in an isochoric process?
Volume
It is also called an isometric or isovolumetric process.
Q 22An isenthalpic process occurs at constant what?
Enthalpy
Isentropic, a reversible adiabatic process, is the one that holds entropy constant.
Q 23Per the zeroth law, if A and B are each at the same temperature as C, then what?
A and B are also in balance
The law is tacitly assumed in every temperature measurement and justifies building thermometers.
Why is the zeroth law called 'zeroth'?
Q 14Which innovation by James Watt greatly improved steam engine efficiency?
The external condenser
Watt conceived it while employed as an instrument maker at Glasgow alongside Joseph Black.
Q 15Who wrote the first thermodynamics textbook in 1859?
William Rankine
Originally trained as a physicist, he was a professor of civil and mechanical engineering at Glasgow.
Q 16What did Clausius's 1850 paper 'On the Moving Force of Heat' first state?
The second law
It earned him the title of one of the founding fathers of thermodynamics.
Q 17Which American published 'On the Equilibrium of Heterogeneous Substances' in the 1870s?
Josiah Willard Gibbs
His graphical methods showed whether a process, including a chemical reaction, would occur spontaneously.
Q 18Who presented a purely mathematical, axiomatic thermodynamics in 1909?
Constantin Carathéodory
His approach, using adiabatic accessibility, is often called geometrical thermodynamics.
Q 19A process that occurs with no heat exchange is called what?
Adiabatic
A reversible adiabatic process also keeps entropy constant and is called isentropic.
Q 20What stays constant during an isobaric process?
Pressure
Isochoric processes, by contrast, hold volume fixed.
It was added after the others
The first, second and third laws were already accepted, and renumbering them was impractical.
Q 25What does the third law say happens as temperature approaches absolute zero?
Entropy reaches a minimum
A consequence is that absolute zero cannot be reached in a finite number of steps.
Q 26Which pair are the 'thermal' conjugate variables in thermodynamics?
Temperature and entropy
Pressure-volume are the mechanical pair, and chemical potential-particle number the material pair.
Q 27Which two potentials give the work available at fixed T and V, or fixed T and p?
Helmholtz and Gibbs energies
They cannot be measured directly in a lab but can be computed from molecular thermodynamics.
Q 28A negative change in Gibbs free energy indicates what kind of process?
Spontaneous
The relation is ΔG = ΔH − TΔS, with T in kelvin.
Q 29Who gave entropy its statistical meaning as a count of microscopic arrangements?
Ludwig Boltzmann
His logarithmic law carries a proportionality constant, now one of the SI's defining constants.
Q 30In what year did Boltzmann define entropy via the logarithm of the number of microstates?
1877
The Boltzmann constant is the proportionality factor in that definition.