This NOVA video is hosted by Derek Muller, the creator of the Veritasium YouTube channel, who takes a journey to explore the history and use of uranium. Born in an exploding star, uranium became incorporated into the early earth. Seen as useless for much of history, uranium became used as an ingredient in glassmaking. After the discovery of radiation, uranium was recognized as a potential energy source for the generation of power, and of atomic bombs. The fear of a Nazi uranium bomb led to the United States developing and using atomic bombs in World War II.
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NOVA Uranium: Twisting the Dragon's Tail, Episode 01
Physicist Derek Muller, host of the Veritasium YouTube channel, explores the origin, early history, and uses of uranium in war and the generation of electricity.
Uranium is formed in exploding stars. As the earth, sun and planets formed in a giant rotating nebula, uranium and other elements were incorporated. Earth’s uranium later became concentrated in rocks due to various geological processes. These rocks are found in Europe, the United States, and Australia.
Muller begins his exploration of uranium at the Joachimstal silver mine in the Czech Republic. The miners originally thought the uranium bearing rock to be useless, and they discarded piles of this material outside of the mine. The rock was named “pecheblende” meaning “hard luck rock” because the finding of pecheblende meant that the silver veins had run out. In the mine, pecheblende can be seen as a fluorescent glow under a UV blacklight. First identified as an element in 1789, uranium was named for the newly discovered planet Uranus. The element’s only use had been in glassmaking to create pale-yellow sparkling glassware that also glows under a black light.
French physicist Henri Becquerel first discovered radioactivity in uranium when he found that a lump of pecheblende would create a fogged image when placed upon a glass photographic plate. This effect was even created in a dark drawer independent of sunlight. Becquerel reasoned that the rock was emitting invisible, light-like energy. Marie Curie, the first physics “superstar”, studied uranium for her doctoral thesis. She also discovered that uranium bearing rock contained other elements, and she discovered a new, glowing radioactive element named radium. This new element became incorporated in fad-medicine and cosmetics, as well as a working treatment for tumors. Radium bearing bandages were placed upon tumorous growths to reduce them in a pain-free manner.
After seeing a vial of glowing radium at a party hosted by Marie and Pierre Curie, Ernest Rutherford and his partner Frederick Soddy began to study the invisible world of the atomic nucleus. They discovered that the atom of an element such as uranium contains a tiny, central nucleus thousands of time smaller than the atom itself. This nucleus contains smaller particles named protons and neutrons, and the number of protons defines the identity of each element. Hydrogen has one proton, helium has two protons, etc., up to uranium, which contains 92 protons and is the largest nucleus on earth! Rutherford and Soddy also observed that the uranium nucleus ejected pieces of itself containing protons. This caused the atom to change identify and was a scientific discovery of actual “transmutation”, the change of one element into another, that had been unsuccessfully sought by the medieval alchemists. Eventually, through 14 generations of change, uranium finally converts into its “barren daughter” lead. Each step in the transmutation process yields a radioactive element such as Marie Curie’s radium. Lead became a dead end and is an inert, non-radioactive element.
Originally a scientific curiosity, uranium and radiation began to assume their terrifying ascent into our modern world in the early 20th century. In 1905, while working as a patent clerk in Bern, Switzerland, Einstein discovered the most famous equation in science, E=mc2. This equation revealed that matter and energy were two sides of the same thing, and that matter could be converted into energy. Matter also contains an enormous amount of energy in that its mass is multiplied by the speed of light squared, an immense number in its own right. The discovery of the equivalence of mass and energy was incorporated into the plot of a science fiction novel by H.G. Wells named “The World Set Free”. In this novel, atomic energy is liberated from matter to power human civilization, as well as to make “atomic bombs”.
In 1933, Hungarian physicist Leo Szilard realized that the idea of atomic bombs explored in the H.G. Wells novel could actually be possible. He realized that uranium could be forced to undergo a “chain reaction” in which the decay of a uranium nucleus would provide a neutron to strike and split an adjacent uranium nucleus, and so on and so on ad infinitum... Szilard also realized that Germany under Adolf Hitler and the Nazis had the scientific know-how to potentially create a uranium-based bomb. In 1939, Szilard learned that German chemist Otto Hahn had successfully split the uranium nucleus achieving the reaction necessary to power an atomic bomb. The Nazis had also just annexed the Czech Republic and had the only source of uranium in Europe at their disposal.
After fleeing Europe, Szilard met Albert Einstein in New York. Einstein had also fled Europe along with a large number of Jewish scientists who had been persecuted by the Nazis. Szilard and Einstein composed a letter to President Roosevelt expressing their concern about a German uranium bomb. Being a scientific celebrity, Einstein was able to have a letter reach the president. Roosevelt took the proposal seriously and started an effort to make an American atomic bomb. Named the Manhattan Project, the program developed the first atomic bombs at a secret city in New Mexico named Los Alamos. After Germany surrendered in 1945, the Americans realized that Germany had not seriously pursued atomic weapons, yet the Manhattan Project was continued, and weapons were developed to use in the war against Japan. (Szilard, becoming the world’s first “antinuclear activist”, wrote the president in an attempt to stop the project). The Manhattan Project represented science on an industrial scale at the cost of billions of dollars. The rare uranium isotope U-235 was enriched from regular uranium. This was the type of uranium susceptible to the chain reaction visualized by Szilard. A mass of U-235 enriched to 80% purity was fashioned into a basketball sized sphere and would form the core of an atomic bomb. The first atomic bomb was detonated at a place in New Mexico named Jornada del Muerto. The actual bomb site is named Trinity, where a stone monument has been erected today. Fragments of green glass, trinitie, fused from desert sand by the heat of the blast are found here. When discussing the Trinity Test, Robert Oppenheimer famously quoted from the Hindu scripture Bhagavad Gita: “Now I am become death, the destroyer of worlds.”
The first atomic bomb used against other humans was dropped on Hiroshima Japan on the morning of August 6, 1945 by a lone, gleaming silver aircraft named the Enola Gay. The single bomb blasted the city into a ruined plain. Later, survivors became afflicted with a horrible new illness named acute radiation sickness. Eventually over 100,000 people would die from the Hiroshima atomic bomb.
The story of uranium and its controversial use in power generation is told in Episode 2 of NOVA Uranium: Twisting the Dragon’s Tail.
