10 Facts About Silicon


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.

Silicon is a metalloid: an element with properties not quite like a metal, nor exactly like a non-metal. If you have a cell phone in your pocket or dirt on your shoes, you’re carrying silicon. Learn more about this ever-present element.


It's the seventh most abundant element in the universe and even more prevalent in the Earth's crust, second only to oxygen as the most common element by weight. The layer under the crust—the mantle—is rich in silicon as well. With an atomic number of 14, it sits right below carbon on the periodic table.



The word silicone might make you think of breast implants, but it's actually a general term for a group of synthetic substances made of alternating silicon and oxygen atoms, with carbon and hydrogen molecules bonded on the sides. By mixing up these side groups of molecules and creating links between chains, chemists can create silicones with all sorts of different properties. Yes, you can find silicones in breast implants, but also in car polish, the insulation around electric cables, and even in your hair conditioner, where they help to calm down frizz. We can also thank silicones for Silly Putty, which was invented during World War II, when scientists were trying to create an alternative to rubber—and instead came up with a new national favorite toy.


Silica is the main ingredient of glass, which humans have been making at least since the Egyptians fashioned beads from the material in 2500 BCE. In China, the Qin and Han dynasties used purple and blue pigments made of barium copper silicates for various decorations, including parts of the famous terra-cotta army.

It took many centuries before people realized the substance could be further separated into two different elements—oxygen and silicon. In the late 1700s, French chemist Antoine Lavoisier noticed that certain materials classified as “earth” substances (which were dry and cold) sometimes behaved like metals (hard, dense, and resistant to being stretched, among other qualities). Silica was one of them. Perhaps, Lavoisier mused, some of the earths were really molecules of oxygen and a yet-undiscovered, metal-like element.

At the time, chemists didn’t know how to remove the oxygen atoms, which form strong bonds with the silicon atoms. That changed in the 1820s, when a Swedish chemist named Jons Berzelius finally managed to obtain silicon in his lab by purifying it from a silicon-containing compound. (Which one, and how he did it, isn't clear.) Berzelius's breakthrough came too late for Lavoisier, who had died in 1794, to see his speculations be proven true.


Also known as silicon dioxide, this molecule is composed of one silicon atom and two oxygen atoms (SiO2). Most of what we call silicon is actually silica, found in both minerals and plants. Many plants create unique microscopic structures called phytoliths using silica they take up from the soil. Scientists aren't sure why: They might offer protection against microscopic harm or provide structural support, or maybe they're just a way for a plant to use up extra silica.

Phytoliths stick around long after a plant decays, which can illuminate the deep history of an area—whether it used to be a forest or grassland, for instance, or how people used the landscape. Dan Cabanes, a phytolith expert and anthropologist at Rutgers University, has used phytoliths to understand how Neanderthals made a home in a cave in northern Spain, creating a sleeping area with grass bedding they used repeatedly. And because phytoliths survive burning, “we can study how they made fire or what type of food they were consuming,” Cabanes tells Mental Floss.

The picture isn’t always perfect, though, because sometimes two different plants make phytoliths of the same shape—and some plants don’t make them at all.



Gorgeous gemstones like amethyst, onyx, and agate are all made of silica. In each rock, the silica molecules are arranged in repeating 3D geometries called crystal structures. Different arrangements, as well as small impurities in the rock, give each gemstone its unique appearance.


Anatoly Mikhaltsov, Wikimedia Commons // CC BY-SA 4.0

Silica also forms the cell walls of diatoms, a type of algae found all over the world. Diatoms, which come in a mesmerizing variety of shapes, can live in both fresh and saltwater. When they die, their cell walls can accumulate into chalky deposits of "diatomaceous earth," which we use in all sorts of things, from cat litter to toothpaste.


Silicon can act as a semiconductor—a material that neither conducts electricity perfectly nor insulates against it, but rather lies somewhere in between. This property is important in many parts of electronics, where you want some control over the flow of electricity. “What's beautiful about semiconductors is that you can tune their conductivity by adding impurities,” Eric Pop, a professor of electrical engineering at Stanford University, tells Mental Floss. Pure silicon is an insulator, but if you ‘dope’ it with tiny amounts of certain other elements, such as phosphorus or arsenic, it becomes better at conducting electricity.

Other materials, including germanium or gallium arsenide, are better semiconductors than silicon, but silicon is the most popular choice among electronics manufacturers (whose concentration south of San Francisco in the 1970s inspired the name "Silicon Valley"). It's cheap, it’s everywhere, and because it likes to oxidize so much, it can conveniently create its own insulating layer when exposed to air.


Engineers like Pop are looking for materials to replace silicon in our electronics to help keep up with the demand for faster computing. “Silicon is sort of like the Honda Civic of semiconductors,” Pop says. “It gets the job done, but it’s not very fast.” However, Pop thinks that even when pitted against superior materials, silicon won’t completely disappear, thanks to its low cost.



Many common building materials are based on silicon-containing substances. Clay minerals, which contain silicon, are used to make bricks, as well as Portland cement, which is then used as the binding agent in concrete.


When Buzz Aldrin and Neil Armstrong became the first humans to walk on the Moon, in 1969, they left a few things on its surface besides their footprints. One was a small silicon disc, inscribed with messages from the leaders of 73 countries, from Afghanistan to Zambia. The disc is housed inside a protective aluminum case and is stashed in a small bag along with a few other items. Silicon was elected official message-bearer because it could endure the huge range of temperatures on the Moon. The disc nearly didn’t make it, though: Aldrin had forgotten all about the bag, tucked into a pocket of his space suit sleeve, and he was already on the ladder to the spacecraft when Armstrong reminded him about it. Aldrin tossed the pouch onto the Moon.

Kodak’s New Cameras Don't Just Take Photos—They Also Print Them

Your Instagram account wishes it had this clout.
Your Instagram account wishes it had this clout.

Snapping a photo and immediately sharing it on social media is definitely convenient, but there’s still something so satisfying about having the printed photo—like you’re actually holding the memory in your hands. Kodak’s new STEP cameras now offer the best of both worlds.

As its name implies, the Kodak STEP Instant Print Digital Camera, available for $70 on Amazon, lets you take a picture and print it out on that very same device. Not only do you get to skip the irksome process of uploading photos to your computer and printing them on your bulky, non-portable printer (or worse yet, having to wait for your local pharmacy to print them for you), but you never need to bother with ink cartridges or toner, either. The Kodak STEP comes with special 2-inch-by-3-inch printing paper inlaid with color crystals that bring your image to life. There’s also an adhesive layer on the back, so you can easily stick your photos to laptop covers, scrapbooks, or whatever else could use a little adornment.

There's a 10-second self-timer, so you don't have to ask strangers to take your group photos.Kodak

For those of you who want to give your photos some added flair, you might like the Kodak STEP Touch, available for $130 from Amazon. It’s similar to the regular Kodak STEP, but the LCD touch screen allows you to edit your photos before you print them; you can also shoot short videos and even share your content straight to social media.

If you want to print photos from your smartphone gallery, there's the Kodak STEP Instant Mobile Photo Printer. This portable $80 printer connects to any iOS or Android device with Bluetooth capabilities and can print whatever photos you send to it.

The Kodak STEP Instant Mobile Photo Printer connects to an app that allows you to add filters and other effects to your photos. Kodak

All three Kodak STEP devices come with some of that magical printer paper, but you can order additional refills, too—a 20-sheet set costs $8 on Amazon.

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

10 Facts About the Element Lead


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.