Plutonium Trivia
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49 free Plutonium trivia questions with answers — science & nature quiz, new questions added Oct 2026.
This plutonium trivia quiz covers element 94 from the Berkeley cyclotron in 1940 to the power packs still running the Voyager probes. The easy questions handle the basics: the symbol, the atomic number, the planet it was named for, the bomb it fuelled and the spacecraft it powers. From there it moves through the physics and chemistry: six allotropes, the strange melting behaviour, gallium alloys, plutonium-239 versus plutonium-240, half-lives and what makes a sample weapons-grade. The harder half is for science and history buffs: Fermi's phantom 'hesperium', the name Seaborg almost chose, the X-10 reactor and Hanford's 'Queen Mary' buildings, Thin Man versus Fat Man, the Urchin initiator, the demon core, the human injection experiments, Rocky Flats, PUREX and MOX fuel, and the plutonium pacemakers still ticking in 2007. If you enjoyed our periodic table or Manhattan Project quizzes, this is the deep dive on one element. Every answer was checked against the encyclopaedia entry for plutonium before publishing.
30 of 49 questions with answers and explanations. Play the quiz
Q 01What is plutonium's chemical symbol?
Pu
Pu: the team leader picked the letters as a joke about a bad smell, expecting to be overruled, but nobody objected and the symbol became official.
Q 02Plutonium is named for Pluto, which in turn takes its name from the Roman god of what?
The underworld
The underworld: the name simply continued a run of planet-named elements, yet a god of the dead proved a grimly fitting namesake for the metal of the atomic bomb.
Q 03Where was plutonium first synthesised, in 1940-41?
Berkeley, California
Berkeley, California: the university's laboratory went on to find so many new elements that two of them, berkelium and californium, carry the names of the town and the state.
Q 04Which chemist led the team that first produced and identified plutonium?
Glenn T. Seaborg
Glenn T. Seaborg: he broke the news of two further elements on a children's radio quiz show in 1945, days before the formal announcement, after a young panellist asked whether any more had been found.
Q 05Why did the paper announcing plutonium's discovery go unpublished for years?
Wartime secrecy
Wartime secrecy: the team sent its paper to Physical Review in March 1941, but it was held back on security grounds, and the public first heard the word plutonium only after the atomic bombings of 1945.
Q 06Which element, found months earlier in the same laboratory, sits just before plutonium in the periodic table?
Neptunium
Neptunium: Edwin McMillan made element 93 in 1940 and began hunting for element 94, but he was called away to defence work on radar, leaving his colleagues to finish the job.
Q 07Which Italian physicist's team wrongly reported finding element 94 in 1934, later calling it hesperium?
Enrico Fermi
Enrico Fermi: his samples were really fragments of split uranium atoms, so he had achieved nuclear fission four years before anyone recognised it, and his 1938 Nobel Prize cited those supposed new elements.
Q 08What are plutonium's six different solid forms called?
Allotropes
Allotropes: plutonium's six differ so much in density that a warming piece swells and shrinks, which makes the metal notoriously hard to machine.
Q 09Which 1985 film's time machine runs on plutonium its inventor conned out of Libyan terrorists?
Back to the Future
Back to the Future: Doc Brown's DeLorean needs plutonium to generate 1.21 gigawatts, so Marty, stranded in 1955 without any, has to catch a lightning bolt to get home.
Q 10Which country's first nuclear test, in 2006, used plutonium from a reactor it had once agreed to freeze?
North Korea
North Korea: it shut its Yongbyon reactor under a 1994 deal with the United States, restarted it after the deal broke down in 2002, and tested a plutonium bomb four years later.
Q 11Which physicist directed the laboratory that designed the first plutonium bomb?
J. Robert Oppenheimer
J. Robert Oppenheimer: he urged that the bomb's scientists be gathered at one isolated site, and the Army took over a remote boys' school on a mountain mesa to house them.
Q 12What fruit-inspired name do weapon designers give the plutonium core of a nuclear warhead?
The pit
The pit: it sits like a peach stone at the centre of the weapon, and in a modern hydrogen bomb the plutonium is only the trigger that sets off the far larger fusion stage.
Q 13Which element, one step beyond plutonium in the periodic table, is found in many household smoke detectors?
Americium
Q 21Plutonium's radioactivity consists mainly of which type of radiation?
Alpha particles
Alpha particles: a sheet of paper stops them, so the plutonium-238 in a spacecraft generator needs almost no shielding and nearly all of its energy stays behind as usable heat.
Q 22What made plutonium at Oklo, Gabon, nearly two billion years before humans did?
A natural reactor
A natural reactor: groundwater seeping through rich uranium ore set off chain reactions that ran on and off for hundreds of thousands of years, and the plutonium they made stayed put.
Q 23Which plutonium-powered probe flew past Pluto in 2015, the dwarf planet its fuel is named after?
New Horizons
Americium: it builds up as plutonium-241 decays, and a tiny speck in an alarm charges the air so that a current flows until smoke gets in the way.
Q 14What is the half-life of plutonium-239?
24,100 years
24,100 years: half of any sample is still there after that long, which is why plutonium waste is buried deep in rock instead of being stored until it fades.
Q 15Enola Gay dropped the first atomic bomb; which B-29 dropped the second, a plutonium weapon, three days later?
Bockscar
Bockscar: named for its usual commander, Frederick Bock, it could not reach its reserve fuel that day and had just enough left to limp to Okinawa after the drop.
Q 16Plutonium would detonate too early in a gun-type bomb, so Fat Man relied on which method instead?
Implosion
Implosion: shaped explosive charges squeezed a plutonium sphere from every side at once, a design so uncertain that it had to be proven in the desert before anyone would trust it in combat.
Q 17Which country's first nuclear test, 1974's 'Smiling Buddha', used plutonium from a Canadian-supplied research reactor?
India
India: it called the blast a peaceful nuclear explosion, but the shock led supplier countries to form a club to stop reactor plutonium being diverted to bombs again.
Q 18Which of these Mars rovers runs on a plutonium-powered generator instead of solar panels?
Curiosity
Curiosity: its radioisotope thermoelectric generator turns the heat of decaying plutonium-238 into electricity, so the rover keeps working through the nights and dust storms that starve solar panels.
Q 19Which twin spacecraft have run on plutonium-238 generators since their launch in 1977?
The Voyagers
The Voyagers: their generators lose about four watts of output every year as the plutonium decays, so engineers have switched off heaters and instruments one by one to keep the mission going.
Q 20Before lithium batteries took over, plutonium-238 powered which implanted medical device?
Heart pacemakers
Heart pacemakers: a plutonium cell could outlast its wearer and spare repeat surgery to change batteries.
New Horizons: nine years out from the Sun and far beyond the reach of solar panels, the probe ran its cameras on one plutonium generator putting out about 200 watts.
Q 24A plutonium fuel cask from which Apollo mission lies on the Pacific seabed instead of the Moon?
Apollo 13
Apollo 13: the generator fuel meant for a lunar experiment stayed aboard the lander the crew used as a lifeboat, and its cask survived re-entry intact before sinking in deep water.
Q 25Traces of plutonium in most people come mainly from what?
Open-air bomb tests
Open-air bomb tests: hundreds of blasts in the atmosphere spread plutonium around the globe until a 1963 treaty drove most testing underground.
Q 26The first self-sustaining chain reaction, CP-1, was achieved in December 1942 under a football grandstand in which city?
Chicago
Chicago: the pile of graphite and uranium was stacked in a disused squash court beneath the stands, in the middle of a crowded city, and its data shaped the first plutonium-making reactors.
Q 27Where was the Manhattan Project's main plutonium production facility?
Hanford, Washington
Hanford, Washington: planners wanted somewhere isolated with abundant water and power, and the reactors went up along the Columbia River, whose flow cooled them.
Q 28What went wrong at a secret Soviet plutonium plant in the 1957 Kyshtym disaster?
A waste tank exploded
A waste tank exploded: its cooling had failed at Mayak, a plutonium works so secret that it was known only by the code name Chelyabinsk-40.
Q 29Workers building 800-foot plutonium separation plants in 1944 nicknamed them after which ocean liner?
The Queen Mary
The Queen Mary: inside each long concrete 'canyon', operators worked behind seven feet of shielding, steering the machinery by periscope and television because the process was too radioactive to approach.
Q 30Which gun-type plutonium weapon design was abandoned because reactor plutonium had too much plutonium-240?
Thin Man
Thin Man: stray neutrons from plutonium-240 would have started the chain reaction before a gun could bring the pieces together, so in summer 1944 the weapon laboratory was reorganised around a new design.