Physics Trivia
0Loading crowd target
0Loading crowd target
8correct to beat the crowd
This physics trivia quiz runs 110 free questions with answers across the whole subject: the SI units and who they are named after, the constants that hold the universe together, the classic experiments from Cavendish's torsion balance to the LIGO detectors, and the people behind quantum and particle physics. It starts with things most people half-remember from school, such as the speed of light, absolute zero and why the sky is blue, and climbs to questions for real enthusiasts: which metal superconductivity was first seen in, what is carved on Boltzmann's tombstone, and who quipped 'Who ordered that?' when the muon turned up. It works as a science round for a pub quiz, a classroom warm-up or a solo test of how much physics you actually retained. Every answer has been checked against an encyclopaedia or primary source, and each question shows its explanation and citation once you have answered, so a disputed fact can be settled on the spot.
30 of 110 questions with answers and explanations. Play the quiz
Q 01Roughly how fast does light travel through empty space?
About 300,000 km per second
Light travels at about 300,000 km per second through empty space, exactly 299,792,458 metres per second; since 1983 the metre has been defined from that speed.
Q 02Whose three laws of motion were first published in the Principia in 1687?
Isaac Newton
Isaac Newton's Principia nearly went unprinted: the Royal Society had spent its book budget on a history of fishes, so the astronomer Edmond Halley paid for publication himself in 1687.
Q 03Which SI unit, symbolised by the Greek letter omega, measures electrical resistance?
Ohm
The ohm honours Georg Ohm, whose 1827 law linking voltage, current and resistance was coldly received; hurt, he resigned his teaching post, and recognition came only with the Royal Society's Copley Medal in 1841.
Q 04What phenomenon makes the daytime sky look blue?
Rayleigh scattering
Rayleigh scattering by air molecules affects short blue wavelengths far more than long red ones, so scattered blue light fills the sky; the low Sun turns orange as its blue is scattered away.
Q 05At 20 °C, how fast does sound travel through air?
About 343 metres per second
Sound moves at about 343 metres per second in air at 20 °C, roughly a kilometre every three seconds, which is why you count between lightning and thunder.
Q 06Absolute zero corresponds to which temperature on the Celsius scale?
−273.15 °C
−273.15 °C is the point where an ideal gas's pressure would shrink to nothing; it can be approached but never reached, though physicists have chilled atoms to within billionths of a degree of it.
Q 07Which SI unit of power is named after a Scottish inventor?
Watt
Watt honours James Watt, whose separate condenser made steam engines far more efficient; to compare them with the horses they replaced he popularised 'horsepower', and one horsepower is about 746 of the units named after him.
Q 08Who received the first Nobel Prize in Physics, in 1901, for discovering X-rays?
Wilhelm Röntgen
Wilhelm Röntgen called the rays 'X' because nobody yet knew what they were; he refused to patent them so that everyone could benefit, and gave his Nobel prize money to his university.
Q 09Ignoring air resistance, by roughly how much does a falling object's speed increase each second near Earth's surface?
9.8 m/s
9.8 m/s is added every second; the figure is slightly larger at the poles than at the Equator, so you weigh a little more in Helsinki than in Singapore.
Q 10In the name of CERN's Large Hadron Collider, what is a hadron?
A particle made of quarks
A particle made of quarks bound by the strong force, like the proton; quarks are never seen alone, because pulling one free takes so much energy that a new quark–antiquark pair forms instead.
Q 11Which British physicist is credited with discovering the electron in 1897?
J. J. Thomson
J. J. Thomson showed in 1897 that cathode rays were particles over a thousand times lighter than a hydrogen ion; his son George later won a Nobel for showing electrons diffract like waves.
Q 12Which SI unit is defined as one cycle or event per second?
Hertz
Hertz honours Heinrich Hertz, who proved in the 1880s that the electromagnetic waves theory had predicted were real; he died at 36 in 1894, just before others turned his waves into radio.
Q 13Which particle, proposed in 1964, did CERN's ATLAS and CMS teams announce they had finally found in July 2012?
Higgs boson
Q 21Which SI unit of energy is named after an English physicist who worked in his family's brewery?
Joule
Joule honours James Prescott Joule, who let a falling weight spin a paddle in water and found that a set amount of work always gave the same heat, showing heat is a form of energy and not a fluid.
Q 22Which physicist led the first self-sustaining nuclear chain reaction at Chicago Pile-1 in 1942?
Enrico Fermi
Enrico Fermi's team took Chicago Pile-1 critical on 2 December 1942 in a rackets court under the stands of Stagg Field; the success was reported by phone in an improvised code, as the Italian navigator landing in the New World.
Q 23Which particle did James Chadwick discover in 1932, earning him a Nobel Prize three years later?
The neutron
The Higgs boson is a ripple in a field proposed in 1964 to explain how particles get their mass; Peter Higgs and François Englert shared the Nobel Prize the year after the announcement.
Q 14What random event decides the cat's fate in Schrödinger's 1935 thought experiment?
Radioactive decay
Radioactive decay: if a single atom decays, a Geiger counter trips a hammer that smashes a flask of poison. Schrödinger meant the cat that is at once dead and alive to show how absurd the idea was, not to endorse it.
Q 15Whose principle says buoyant force equals the weight of fluid displaced?
Archimedes
Archimedes' principle, from the Greek mathematician of Syracuse in the third century BC, explains why steel ships float: the displaced water weighs as much as the ship.
Q 16Christian Doppler first proposed his famous effect in an 1842 treatise about the coloured light of what?
Binary stars
Doppler's 1842 paper was titled 'On the coloured light of the binary stars'; his idea that the effect explains star colours was wrong, but the effect itself was right.
Q 17Which SI unit of pressure is named after a French mathematician who experimented with barometers?
Pascal
The pascal honours Blaise Pascal, who in 1648 had a barometer carried up the Puy de Dôme to show that air pressure falls with altitude; weather maps quote hectopascals.
Q 18Albert Einstein's Nobel Prize in Physics was awarded specifically for his work on which phenomenon?
The photoelectric effect
The photoelectric effect, not relativity, is what the citation names; the committee had found no worthy winner in 1921, so Einstein received that year's reserved prize a year late, in 1922.
Q 19Marie Curie won the 1903 Nobel Prize in Physics and a second Nobel in 1911 in which field?
Chemistry
Chemistry: the 1911 prize honoured her discovery of radium and polonium. Amid a press scandal over her private life, a Swedish Academy of Sciences member urged her to stay away; she went to Stockholm and gave her Nobel lecture anyway.
Q 20The Planck constant links a photon's energy to which property of the light?
Its frequency
E = hν: a photon's energy is the Planck constant times its frequency, which is why ultraviolet photons carry more punch than red ones; since 2019 h is fixed at exactly 6.62607015 × 10⁻³⁴ J·s.
The neutron was announced in a letter titled 'Possible Existence of a Neutron' after only about two weeks of experiments; having no charge, it could slip into other atoms' cores, and it was soon being used to split uranium.
Q 24In the acronym LASER, what does the letter S stand for?
Stimulated
Stimulated completes 'light amplification by stimulated emission of radiation'; Gordon Gould coined the acronym in a 1957 notebook, then spent some thirty years fighting to win patents on the laser.
Q 25Superconductivity was discovered in 1911 in which metal, cooled to a few degrees above absolute zero?
Mercury
Heike Kamerlingh Onnes saw the resistance of mercury vanish at about 4.2 K in 1911, having liquefied helium three years earlier; he won the 1913 Nobel Prize for low-temperature work.
Q 26Léon Foucault's famous pendulum of 1851 was the first simple, direct demonstration of what?
The rotation of the Earth
Foucault's pendulum, hung first at the Paris Observatory and then under the Panthéon's dome in 1851, swung in a slowly turning plane, showing the rotation of the Earth directly; he repeated the feat with a gyroscope in 1852.
Q 27Which of the four fundamental forces is by far the weakest?
Gravity
Gravity is weaker than the other three by dozens of orders of magnitude: a fridge magnet lifting a paperclip beats the pull of the whole planet. It still rules at large scales because it reaches any distance and always attracts.
Q 28Murray Gell-Mann took the word 'quark' from which novel?
Finnegans Wake
Finnegans Wake gave Gell-Mann the spelling: he already had the sound 'kwork' in mind, and Joyce's line 'Three quarks for Muster Mark' seemed perfect because his theory then needed just three such particles.
Q 29Which quark flavours make up ordinary matter?
Up and down
Up and down quarks, the two lightest flavours, are the stable ones; the four heavier flavours quickly decay into them, so they turn up only briefly in accelerators and cosmic-ray collisions.
Q 30Which observatory made the first direct detection of gravitational waves in 2015, from two colliding black holes?
LIGO
LIGO's twin detectors in Louisiana and Washington state caught the signal 7 milliseconds apart; they can sense their 4 km arms changing by far less than a proton's width, and the find won a Nobel Prize two years later.