Scientists Are Tweeting About The Strangest Experiments They’ve Ever Done

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Lead (Pb) is one of the most infamous elements in the periodic table. Though it’s now widely known as the source of lead poisoning, humans have been using the heavy metal for thousands of years. It’s soft, has a relatively low melting point, is easy to shape, and doesn’t corrode much, making it incredibly useful. It’s also relatively abundant and easy to extract. But lead is so much more than just No. 82 on the periodic table. Here are 10 facts about the element lead.

1. The element lead is easy to extract.

One reason people have been using lead for so long is because it’s so easy to extract from galena, or lead sulfide. Thanks to lead’s low melting point of 621.4°F (compare that to the melting point of iron, 2800°F), all you have to do to smelt it is put the rocks in a fire, then extract the lead from the ashes once the fire burns out.

Galena is still one of the major modern sources of lead. Missouri, the biggest producer of lead in the U.S. (and home to the largest lead deposits in the world), designated galena as its official state mineral in 1967. Galena is also the state mineral of Wisconsin, where it has been mined since at least the 17th century. Several towns across the U.S. are named after the mineral as well, most notably Galena, Illinois, one of the centers of the American “Lead Rush” of the 19th century.

2. People have been using lead since prehistory.

The oldest smelted lead object ever found was discovered in a cave in Israel in 2012. Researchers have dated the wand-shaped tool—potentially a spindle whorl—to the late 4000s BCE, tracing its origins to lead ores in the Taurus mountains of what is now Turkey.

3. Lead poisoning can be fatal.

Lead has a fairly similar chemical structure to calcium. Both have two positively charged ions. Because of that, inside the body, the toxic metal can bind to the same proteins as the vital mineral. Over time, lead poisoning occurs as the element crowds out the minerals your body needs to function, including not just calcium, but iron, zinc, and other nutrients.

Lead can travel through the body in the same way that those minerals can, including passing through the brain-blood barrier and into the bones. As a result, exposure to lead—whether through paint, pipes, contaminated soil, or any other means—can be very dangerous, especially for children, for whom lead poisoning can cause learning disabilities, delayed growth, brain damage, coma, and death. Scientists believe there is no safe threshold for lead exposure.

4. Ancient Romans really loved lead.

Lead use reached new heights during the Roman Empire. Ancient Romans used lead to make cookware, water pipes, wine jugs, coins, and so much more. Lead acetate was even used as a sweetener, most often in wine. As a result of ingesting a little lead with every bite of food and sip of water or wine, modern researchers have argued that two-thirds of Roman emperors (as well as plenty of common folk) exhibited symptoms of lead poisoning. A 20th-century examination of the body of Pope Clement II, who died in 1047, showed that lead poisoning led to the religious leader’s sudden demise, too—though there’s still some speculation of whether he was poisoned by an enemy or if he simply drank too much lead-sweetened wine.

5. Lead is a very stable element.

Lead atoms are “doubly magic.” In physics, the numbers 2, 8, 20, 28, 50, 82, and 126 are considered “magic” because those numbers of protons or neutrons completely fill up the atomic nucleus. Lead has 126 neutrons and 82 protons—two magic numbers. As a result, lead isotopes are incredibly stable. Lead-208 is the heaviest stable atom.

6. Lead made car engines quieter—at a high cost.

It’s not surprising that we no longer add lead to gasoline (TIME magazine called it one of the world’s worst inventions back in 2010). But why was it ever there in the first place?

In 1921, a General Motors researcher discovered that adding tetraethyl lead to gasoline reduced “engine knock” in cars, when pockets of air and fuel explode in the wrong place and time in a combustion engine. In addition to producing a loud sound, it also damages the engine. While there were other available chemicals like ethanol and tellurium that could similarly provide the octane boost to reduce knocking, leaded gasoline was easier and cheaper to produce, and unlike tellurium, it didn’t reek of garlic.

Unfortunately, it came at a high cost for the refinery workers that produced leaded gasoline (who many of whom were sickened, driven mad, and killed by their exposure to it) and the environment as a whole.

In the 1960s, geochemist Clair Patterson was trying to measure the exact age of the Earth when he discovered a shocking amount of lead contamination in his lab—and everything he tested, from his tap water to dust in the air to his skin and samples of his dandruff. As he continued to experiment, he discovered that lead levels in ocean water began to rise drastically around the same time that lead became a common gasoline additive. Every car on the road was belching lead straight into the atmosphere.

Patterson would later become the driving force in forcing the U.S. government to ban leaded gasoline. (You can read more about him in our feature, “The Most Important Scientist You’ve Never Heard Of.”)

7. Lead was used in paintings …

Historically, lead wasn’t just prized for being an easy-to-shape metal; it was also valued for its color. Though most of us know that lead was historically used in house paint (and still continues to hide in the walls of some homes today), it was also a popular ingredient in fine art for thousands of years.

Produced since antiquity, lead white (also known as Cremnitz white) was a favorite paint pigment of the Old Masters of the 17th and 18th centuries, including artists like Johannes Vermeer and Rembrandt van Rijn.

“For two millennia, white leads—basic lead carbonate and sulfate—were the only white pigments that could deliver moderately durable whiteness and brightness into a drab world of grays and earth colors,” pigment experts Juergen H. Braun and John G. Dickinson wrote in the third edition of Applied Polymer Science: 21st Century in 2000. Like a number of other pigments prior to the advent of synthetic paints, its toxicity was general knowledge, but for many painters, the risk was worth it to achieve the color they wanted. You can still buy it today, but it has largely been replaced with the safer titanium white.

Lead white isn’t the only lead paint lurking in many famous paintings from history. Dutch artists like Vermeer also favored lead tin yellow, which you can see in his masterpiece The Milkmaid.

8. … and in makeup.

During the 18th century, both men and women used white lead powder to achieve fashionably ghostly complexions, though it was known to be toxic. They powdered their hair with white lead powder, too. The dangerous trend caused eye inflammation, tooth rot, baldness, and eventually, death. To top it off, using lead powder made the skin blacken over time, so wearers needed to apply more and more of the powder to achieve their intended look. Queen Elizabeth I, who lost most of her teeth and much of her hair by the end of her life, reportedly was wearing a full inch of lead makeup on her face when she died. While her cause of death remains unclear, one popular theory holds that she was killed by blood poisoning from her longtime reliance on those lead-filled cosmetics.

Researchers have hypothesized that several other famous historical figures either suffered from or died from lead poisoning, including painters like Vincent van Gogh and Francisco Goya. In several cases, exhumations have proved this: A 2010 analysis of what are thought to be Caravaggio’s bones showed very high levels of lead (enough to drive him crazy, if not outright kill him) likely from his exposure to lead paint throughout his life. Hair and skull fragments believed to belong to Ludwig van Beethoven also show very high lead levels, potentially from the wine he drank.

9. Lead is a superconductor.

Which means that if it is cooled below a certain temperature, it loses all electric resistance. If you were to run a current through lead wire that has a temperature below 7.2K (-446.71°F), it would conduct that current perfectly without losing any energy to heat. A current running through a lead ring could continue flowing forever without an outside energy source.

Like other superconductors, lead is diamagnetic—it is repelled by magnetic fields.

10. On Venus, it snows lead.

Venus is the hottest planet in the solar system, with an average surface temperature of 867°F. That’s far above lead’s 621.4°F melting point. In 1995, scientists discovered what appeared to be metallic “snow” on the mountains of Venus—a planet too hot to have water ice. In 2004, researchers at Washington University in St. Louis discovered that Venusian “snow” was probably a mixture of lead sulfide and bismuth sulfide.

This “snow” forms because Venus’s high temperatures vaporize minerals on the planet’s surface, creating a kind of metallic mist that, when it reaches relatively cooler altitudes, condenses into metallic frost that falls on the planet’s tallest peaks.

Source: http://mentalfloss.com/article/572301/Twitter-trending-scientists-tweet-strangest-experiments

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