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Uranium glass vessels.
Uranium glass vessels.
Attila Kisbenedek/AFP/Getty Images

8 Essential Facts About Uranium

Uranium glass vessels.
Uranium glass vessels.
Attila Kisbenedek/AFP/Getty Images

How well do you know the periodic table? Our series The Elements explores the fundamental building blocks of the observable universe—and their relevance to your life—one by one.

Uranium took some time asserting itself. For centuries, heaps of it languished in waste rock piles near European mines. After formal discovery of the element in the late 18th century, it found a useful niche coloring glass and dinner plates. In the first half of the 20th century, scientists began investigating uranium's innate potential as an energy source, and it has earned its place among the substances that define the "Atomic Age," the era in which we still live. Here are some essential facts about U92.

1. IT'S THE HEAVIEST NATURALLY OCCURRING ELEMENT IN THE UNIVERSE.

With a nucleus packed with 92 protons, uranium is the heaviest of the elements. That weight once compelled shipbuilders to use spent uranium as ballast in ship keels. Were it employed that way now, sailing into port could set off defense systems.

Uranium was first found in silver mines in the 1500s in what's now the Czech Republic. It generally appeared where the silver vein ran out, earning it the nickname pechblende, meaning "bad luck rock." In 1789, Martin Klaproth, a German chemist analyzing mineral samples from the mines, heated it and isolated a "strange kind of half-metal"—uranium dioxide. He named it after the recently discovered planet Uranus.

French physicist Henri Becquerel discovered uranium's radioactive properties—and radioactivity itself—in 1896. He left uranyl potassium sulfate, a type of salt, on a photographic plate in a drawer, and found the uranium had fogged the glass like exposure to sunlight would have. It had emitted its own rays.

2. ITS TRANSFORMATIONS PROVED THE ALCHEMISTS RIGHT … A LITTLE.

Uranium decays into other elements, shedding protons to become protactinium, radium, radon, polonium, and on for a total of 14 transitions, all of them radioactive, until it finds a resting point as lead. Before Ernest Rutherford and Frederick Soddy discovered this trait around 1901, the notion of transforming one element into another was thought to be solely the territory of alchemists.

3. IT'S HIGHLY UNSTABLE.

Uranium's size creates instability. As Tom Zoellner writes in Uranium: War, Energy, and the Rock That Shaped the World, "A uranium atom is so overloaded that it has begun to cast off pieces of itself, as a deluded man might tear off his clothes. In a frenzy to achieve a state of rest, it slings off a missile of two protons and two neutrons at a velocity fast enough to whip around the circumference of the earth in roughly two seconds."

4. IF YOU INGEST IT, THANK YOUR KIDNEYS FOR KEEPING YOU ALIVE.

Traces of uranium appear in rock, soil, and water, and can be ingested in root vegetables and seafood. Kidneys take the burden of removing it from the bloodstream, and at high enough levels, that process can damage cells, according to the Argonne National Laboratory. But here's the good news: After short-term, low-level exposures, kidneys can repair themselves.

5. URANIUM MADE FIESTA WARE COLORFUL … AND RADIOACTIVE.

Before we recognized uranium's potential for energy—and bombs—most of its uses revolved around color. Photographers washed platinotype prints in uranium salts to tone otherwise black and white images reddish-brown. Added to glass, uranium gave beads and goblets a canary hue. Perhaps most disconcertingly, uranium makes Fiesta Ware's red-orange glaze—a.k.a. "radioactive red"—as hot as it looks; plates made before 1973 still send Geiger counters into a frenzy.

6. "TICKLING THE DRAGON'S TAIL" WAS KEY TO MAKING THE FIRST ATOMIC BOMBS.

Uranium occurs naturally in three isotopes (forms with different masses): 234, 235, and 238. Only uranium-235—which constitutes a mere 0.72 percent of an average uranium ore sample—can trigger a nuclear chain reaction. In that process, a neutron bombards a uranium nucleus, causing it to split, shedding neutrons that go on to divide more nuclei.

In the 1940s, a team of scientists began experimenting in the then-secret city of Los Alamos, New Mexico, with how to harness that power. They called it "tickling the dragon's tail." The uranium bomb their work built, Little Boy, detonated over the Japanese city of Hiroshima on August 6, 1945. Estimates vary, but the detonation is thought to have killed 70,000 people in the initial blast and at least another 130,000 more from radiation poisoning over the following five years.

The same property that powered bombs is what now makes uranium useful for electricity. "It's very energy dense, so the amount of energy you can get out of one gram of uranium is exponentially more than you can get out of a gram of coal or a gram of oil," Denise Lee, research and development staff member at Oak Ridge National Laboratory, tells Mental Floss. A uranium fuel pellet the size of a fingertip boasts the same energy potential as 17,000 cubic feet of natural gas, 1780 pounds of coal, or 149 gallons of oil, according to the Nuclear Energy Institute, an industry group.

7. THE EARTH CREATED ITS OWN NATURAL NUCLEAR REACTORS BILLIONS OF YEARS AGO.

In the 1970s, ore samples from a mine in what is now Gabon came up short on uranium-235, finding it at 0.717 percent instead of the expected 0.72 percent. In part of the mine, about 200 kilograms were mysteriously absent—enough to have fueled a half-dozen nuclear bombs. At the time, the possibility of nuclear fission reactors spontaneously occurring was just a theory. The conditions for it required a certain deposit size, a higher concentration of uranium-235, and a surrounding environment that encouraged nuclei to continue splitting. Based on uranium-235's half-life, researchers determined that about 2 billion years ago, uranium occurred as about 3 percent of the ore. It was enough to set off nuclear fission reactions in at least 16 places, which flickered on and off for hundreds of thousands of years. As impressive as that sounds, the average output was likely less than 100 kilowatts—enough to run a few dozen toasters, as physicist Alex Meshik explained in Scientific American.

8. AS A POWER SOURCE, IT'S "PRACTICALLY INFINITE."

A 2010 study from MIT found the world had enough uranium reserves to supply power for decades to come. At present, all commercial nuclear power plants use at least some uranium, though plutonium is in the mix as well. One run through the reactors consumes only about 3 percent of the enriched uranium. "If you could reprocess it multiple times, it can be practically infinite," Stephanie Bruffey, a research and development staff member for Oak Ridge National Laboratory, tells Mental Floss. Tons of depleted uranium or its radioactive waste byproducts sit on concrete platforms at nuclear power plants and in vaults at historic weapons facilities around the country; these once temporary storage systems have become a permanent home. 

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The Elements
10 Quick Facts About Cobalt
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How well do you know the periodic table? Our series The Elements explores the fundamental building blocks of the observable universe—and their relevance to your life—one by one.

Cobalt hides out in everyday objects and happenings around us, from batteries and blue paint to medical procedures. We've used it for millennia, even before the common era, but it didn't get proper credit until the 18th century. With its 27 protons, cobalt is sandwiched between iron and nickel in the middle portion of the periodic table with the other "transition" metals, which bridge the main group elements located on either side. Here are ten curious facts about this element.

1. PURE COBALT DOES NOT NATURALLY EXIST ON EARTH.

Though you can find cobalt just about everywhere—in the soil, in mineral deposits, and even in crusts on the seafloor—it's always combined with other elements like nickel, copper, iron, or arsenic, such as in the bright crimson arsenate mineral erythrite. It's usually collected as a byproduct of mining for other metals—especially nickel and copper—and, once purified, is a burnished gray color.

2. COBALT MAY NOT BE RARE, BUT IT IS VALUABLE.

Despite being relatively common, it's considered a critical raw material by the European Union because there are few places where it's abundant enough to be mined in larger quantities. The only mine in the world where it's the primary product is in Morocco.

3. COBALT WAS NAMED AFTER SUBTERRANEAN GERMAN GOBLINS.

Centuries ago, miners in the mountains of Germany had a great deal of trouble trying to melt down certain ores for useful metals like silver and copper, and even dealt with poisonous fumes released from the rock, which could make them very sick or even kill them. They blamed the kobolds—pesky, underground sprites of local folklore (and more recently, the name of a Dungeons & Dragons species). Though the vapors actually arose from the arsenic also contained in the ores, when chemists later extracted cobalt from these minerals, the name stuck.

4. COBALT WAS FINALLY ISOLATED IN THE 18TH CENTURY.

It was not until the 1730s that Swedish chemist George Brandt purified and identified cobalt from arsenic-containing ores, then another 50 years until Torbern Bergman, another Swede, verified Brandt's new element. It is worth noting, though, that at the time the elements were simply in an incomplete list and had not been organized into a meaningful table.

5. COBALT IS BEST KNOWN FOR CREATING A RICH BLUE HUE…

People have been using cobalt-containing pigments to get that rich blue hue as far back as the 3rd millennium BCE, when Persians used them to color their necklace beads. From Egypt to China, artisans created blue glass from cobalt compounds for thousands of years. The color was long attributed to the element bismuth, depriving cobalt of pigment fame. 

6. … BUT COBALT MAKES OTHER COLORS TOO.

The famed "cobalt blue" is actually the result of the compound cobalt aluminate. Cobalt in other chemical combinations can also make a variety of other colors. Cobalt phosphate is used to make a violet pigment, and cobalt green is achieved by combining cobalt oxides with zinc oxides.

7. TODAY WE USE COBALT TO MAKE POWERFUL MAGNETS AND "SUPERALLOYS."

Cobalt is one of the few elements that are ferromagnetic, which means it can become magnetized when exposed to an external magnetic field. Cobalt remains magnetic at extremely high temperatures, making it very useful for the specialized magnets in generators and hard drives. When mixed with the right metals, cobalt can also help create materials called "superalloys" that keep their strength under huge stress and high temperatures—advantageous, for instance, in a jet engine. Most people, however, can find cobalt hiding closer to home, inside some rechargeable batteries.

8. COBALT COULD ONE DAY REPLACE PRECIOUS METALS IN INDUSTRY.

Scientists such as chemist Patrick Holland at Yale University are looking at ways to use cobalt in place of the more rare and expensive metals often used in industrial catalysts. These catalysts—chemical "helpers" that speed up reactions—are used in making adhesives, lubricants, or pharmaceutical precursors, for instance. Precious metals like platinum and iridium often make good catalysts, but they are also pricey, can be toxic to humans, and, as precious implies, are not abundant. There is a "big upswing in people looking at iron, nickel, and cobalt because of their price," Holland tells Mental Floss.

All three could be viable options in the future. The challenge, Holland says, is "walking the tightrope" between creating an effective, reactive catalyst and one that is too reactive or overly sensitive to impurities.

9. COBALT HAS MULTIPLE ROLES IN MODERN MEDICINE.

The metal perches in the middle of the impressively complex molecule vitamin B12—a.k.a. cobalamin—which is involved in making red blood cells and DNA, and helps keep your nervous system healthy. Cobalt also lends an extra distinction to B12: It's the only vitamin that contains a metal atom.

To measure B12 intake in patients, doctors use a "labeled" version of B12 in which the cobalt atom is replaced with a radioactive cobalt isotope. Oncologists and technicians also use the radiation from cobalt isotopes in some cancer therapies as well as to sterilize medical and surgical tools. These days, cobalt alloys are even found in artificial hip joints and knees.

10. COBALT WAS ONCE ADDED TO BEER—WITH DEADLY CONSEQUENCES.

In the 1960s, some breweries added cobalt chloride to their beers because it helped maintain the appealing foam that builds when beer is poured. By 1967, more than 100 heavy beer drinkers in Quebec City, Minneapolis, Omaha, and Belgium had suffered heart failure, and nearly half of them died. At the time, doctors were also administering cobalt to patients for medical reasons without causing this severe effect, so the blame couldn't lie with the metal alone. After studying the remains of the deceased, scientists proposed that the so-called "cobalt-beer cardiomyopathy" had been caused by an unhealthy mélange of cobalt, high alcohol intake, and poor diet. The FDA banned the use of cobalt chloride as a food additive shortly after. 

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The Elements
Sit Down at a Periodic Table That Holds Samples of Every Element
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The periodic table maps out the atomic numbers, electron configurations, and chemical properties of all the elements found on Earth (both in nature and in the lab). But have you ever wondered what a traditional periodic table would look like as a physical table? That’s the question Wolfram Research co-founder Theo Gray asked himself years ago, and the wooden Periodic Table Table was his answer.

As you can see in the video below from Reactions, the furniture piece he built at his office looks like something you might find in your dining room, albeit a little more educational. Its surface features dozens of wooden squares, each one etched with the information for a different element. Beneath each wooden panel, there's a compartment that contains a sample of that element from the real world.

Gray’s table includes straightforward examples of the elements, like a jar of mercury and a chunk of bismuth, as well as some more creative entries like an aluminum knee implant. The 2400-plus items in his collection have long since spilled beyond the table and onto his shelves. While many of the objects are stored within the table itself, in some cases, he has too many examples of one element to keep them in the same spot. Some, like the knee implant, are just too bulky to fit. Valuable elements like gold and dangerous items—like a radioactive bottle of the early 20th-century quack-medicine Radithor—are also kept in more secure locations.

Even Gray’s vast inventory reflects just a small slice of how we see the chemical elements manifested in everyday life. For more examples of where you can find elements in the world around you, check out this illustrated table.

[h/t Reactions]

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