Thermodynamics Trivia
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100 free Thermodynamics trivia questions with answers — science & nature quiz, new questions added Oct 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 100 questions with answers and explanations. Play the quiz
Q 01Why does water boil cooler on Everest?
Lower pressure
Lower pressure: the summit air presses down with only about a third of its sea-level force, so water boils at about 70 °C and food takes far longer to cook.
Q 02Which way does heat never flow on its own?
From a colder body to a hotter one
From a colder body to a hotter one: heat makes that trip only when work forces it, which is why a refrigerator has to be plugged in.
Q 03Which unit was defined as the heat needed to warm one gram of water by one degree Celsius?
The calorie
The calorie comes from calor, Latin for heat; confusingly, the 'Calories' on food labels are kilocalories, each enough to warm a whole kilogram of water by one degree.
Q 04What is absolute zero on the Celsius scale?
−273.15 °C
−273.15 °C is the bottom of the scale, yet matter would not be perfectly still there: quantum mechanics leaves atoms a residual zero-point motion.
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 06Which English physicist used a falling weight to spin a paddle wheel in water and measure heat's mechanical equivalent?
James Joule
James Joule found the churned water warmed by a fixed amount for each unit of work done, evidence that heat is a form of energy, and the SI unit of energy now bears his name.
Q 07Which physicist coined the word 'entropy' in 1865?
Rudolf Clausius
Rudolf Clausius built the word from the Greek for 'transformation' and deliberately made it resemble 'energy', because he saw the two quantities as close relatives.
Q 08At which reading do the Celsius and Fahrenheit scales show exactly the same number?
−40
−40 is the one point where the scales cross: a Fahrenheit degree is only five-ninths the size of a Celsius degree, so its 32-degree head start at freezing has run out by then.
Q 09Which practical problem drove the early development of thermodynamics?
Steam engines
Steam engines were powering British industry long before anyone understood the physics behind them, and Sadi Carnot's 1824 book set out to supply the missing theory.
Q 10Who built the world's first vacuum pump in 1650?
Otto von Guericke
Otto von Guericke, the mayor of Magdeburg, went on to pump the air from two joined copper hemispheres and show that teams of horses could not pull them apart.
Q 11Boyle's Law says which two gas properties are inversely proportional?
Pressure and volume
Pressure and volume: halve a trapped gas's space and its pressure doubles, a rule Boyle published in 1662 after years at an air pump designed by his assistant, Robert Hooke.
Q 12Denis Papin's 1679 'steam digester' was essentially an early what?
Pressure cooker
Pressure cooker: Papin called it an 'engine for softening bones', and to keep the sealed pot from bursting he fitted it with the first safety valve.
Q 13Who developed the concepts of heat capacity and latent heat at the University of Glasgow?
Joseph Black
Q 21What is held constant in an isochoric process?
Volume
Volume stays fixed, so the gas can do no work by expanding and all the heat added goes into its internal energy, as when a sealed tin can is put on a fire.
Q 22Which thermodynamic quantity is written with the symbol H?
Enthalpy
Enthalpy, from the Greek for 'to warm in', only got its name in the early 20th century; before that, the same quantity went by the plain label 'heat content'.
Q 23The zeroth law says two bodies each in thermal equilibrium with a third must share what with each other?
The same temperature
The same temperature: plain as it sounds, this is what lets a thermometer work, since its reading is only its own temperature once it has settled into balance with whatever it touches.
Joseph Black noticed that melting ice soaks up heat without getting any warmer, and reasoned that the heat had become hidden, or 'latent', inside the water.
Q 14Which James Watt innovation slashed the Newcomen engine's appetite for fuel?
The external condenser
The external condenser came to Watt on a walk across Glasgow Green in 1765: condensing the steam in a separate vessel let the cylinder stay hot instead of being chilled on every stroke.
Q 15Thomas Newcomen's 'atmospheric engine', the workhorse of the early 1700s, was used mainly for what job?
Pumping water out of mines
Pumping water out of mines was almost its only use, and it burned fuel so wastefully that curing its appetite became James Watt's great project.
Q 16Which law did the 1850 paper 'On the Moving Force of Heat' first set out?
The second law
The second law emerged as the paper kept Carnot's insight about engines while rejecting the old belief that heat is a fluid that can never be used up.
Q 17Which American published 'On the Equilibrium of Heterogeneous Substances' in the 1870s?
Josiah Willard Gibbs
Josiah Willard Gibbs published it in a little-read Connecticut journal in dense mathematics, so years passed before chemists grasped that it had founded a new branch of their science.
Q 18Which engine ignites its fuel by compression heating alone, with no spark plug?
Diesel engine
The diesel engine compresses air fifteen-fold or more, which heats it past the fuel's ignition point, so the fuel burns as soon as it is injected; Rudolf Diesel patented the cycle in the 1890s.
Q 19A process that occurs with no heat exchange is called what?
Adiabatic
Adiabatic: with no heat getting in or out, any work done on a gas goes straight into its internal energy, which is why air squeezed quickly grows hot.
Q 20What stays constant during an isobaric process?
Pressure
Pressure: 'isobaric' joins the Greek for 'equal' and 'weight', and a gas heated under a freely sliding piston shows it, swelling in size rather than pushing any harder.
Q 24Why is the zeroth law called 'zeroth'?
It was added after the others
It was added after the others: the name dates from the 1930s, when the other three laws were long established, and because it logically comes before them it was slotted in at zero.
Q 25What does the third law of thermodynamics say happens as a system nears absolute zero?
Entropy reaches a minimum
Entropy reaches a minimum, and for a flawless crystal that minimum is exactly zero, which hands chemists a fixed starting line for measuring the absolute entropy of any substance.
Q 26Which gas law says that a gas expands in direct proportion to its absolute temperature?
Charles's law
Charles's law honours Jacques Charles, who worked it out in the 1780s but never published; Joseph Gay-Lussac verified it, put it in print in 1802 and gave him the credit.
Q 27The 1959 lecture 'The Two Cultures' likened not knowing a famous law of thermodynamics to never having read whom?
Shakespeare
Shakespeare: the speaker, C. P. Snow, said he had asked highly educated company to describe the law, the one about entropy, and got a response that was 'cold' and 'negative', his proof that arts and sciences no longer talked.
Q 28A negative change in Gibbs free energy indicates what kind of process?
Spontaneous
Spontaneous: the sign is the whole test, so even a reaction that soaks up heat will run on its own if it is hot enough for the entropy gained to outweigh the cost.
Q 29Who gave entropy its statistical meaning as a count of microscopic arrangements?
Ludwig Boltzmann
Ludwig Boltzmann has the resulting formula, S = k log W, carved on his tombstone, even though he never wrote it down in that form himself: Max Planck did.
Q 30Which gas did Heike Kamerlingh Onnes turn liquid in 1908, making his Leiden lab the coldest spot on Earth?
Helium
Helium turns liquid only about four degrees above absolute zero, and three years later that extreme cold let Onnes discover superconductivity, electric current flowing with no resistance.