← Everything Everywhere Daily: History, Science, Geography & More
Everything Everywhere Daily: History, Science, Geography & More
Sodium: The Dangerous Yet Vital Element
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It is a metal that's part of a mineral that helped build empires, an ion that allows your nerves to fire and your muscles to move, and it's found in your kitchen. It's helped preserve food, shape trade routes, powered industries, and become one of the most common substances around the world. Yet when it's in its elemental form, it can literally be explosive. Learn more about sodium on this episode of Of Everything Everywhere Daily. This episode is sponsored by Quint's. Summer is here, and if you happen to live in a place with actual seasons as I do, that means wearing entirely different clothes. Wool sweaters are great when the temperatures drop, but they're not the best option when you're outside in the sun. Quint's has European linen pants and shirts that are the perfect warm weather upgrade to add to your rotation. Starting at just $34, their T shirts are soft and easy to wear, and their lightweight cotton sweaters are perfect for cool summer nights. I just got two Quint T shirts myself and I love them as always. Everything at quince is priced 50 to 80% less than similar brands, and they can do that by working directly with ethical factories and cutting out the middleman. So so you're paying for quality, not brand markup. Elevate your summer wardrobe. Go to quince.com daily for free shipping on your order and 365 day returns. Now available in Canada too. That's Q U I-N-E.com daily for free shipping and 365 day returns. Quints.com daily. This episode is sponsored by Dripdrop. Travel. Exercise, heat, long days and even just forgetting to drink enough water can all leave you feeling drained. And when that happens, water alone isn't always enough. That's where Drip Drop comes in. Drip Drop uses science based formulas for rapid hydration so you feel results fast while getting three times the electrolytes of leading sports drinks. It has six key electrolytes as well as 15 essential vitamins and nutrients. Drip Drop comes in a variety of flavors including zero sugar options, and it's trusted by athletes, medical professionals, first responders and people who simply want to stay better hydrated. I use the zero sugar version and it tastes great. Right now, Dripdrop is offering my podcast listeners 20% off their first order. Go to dripdrop.com and use promo code everything. That's dripdrop.com promo code everything for 20% off. Stock up now@dripdrop.com and use promo code everything. Sodium is one of the most familiar chemical elements in daily life, even though almost no one Encounters it in its pure metallic form. It's the element behind table salt, Baking soda, Sodium vapor lamps, lye, Many industrial chemicals, and one of the most important electrical signals in the human body. It's also a good example of how an element can be violently reactive in isolation, yet essential and harmless when bound into common compounds. Sodium sits in group one on the left side of the periodic table, with an atomic number of 11 and a single electron in its outermost shell. And that lone valence electron Is the key to nearly everything about sodium's behavior. Because its outermost electron Is held loosely by the nucleus, Sodium readily gives it up to form a positively charged ion, Thereby achieving a stable electron configuration. This eagerness to lose an electron Makes sodium intensely reactive and a strong reducing agent. Pure sodium is a soft, silvery metal. In fact, it's so soft that it can be cut with a knife. When freshly cut, it has a shiny metallic surface, but it quickly tarnishes in the air as it reacts with oxygen and moisture. It has a relatively low boiling point For a metal at about 97.8 degrees Celsius, which means that it melts just below the boiling point of water. And it's also light with a density lower than water. So a piece of sodium would actually float. Perhaps the most famous property of sodium Is its reaction with water. Pure sodium reacts with water to form sodium hydroxide and hydrogen gas. This reaction releases a lot of heat. The heat can ignite the hydrogen gas, which is why sodium thrown into water may fizz, Skate around the surface, Catch fire, or even explode if enough hydrogen and heat build up. And this isn't just a chemistry class stunt. It is a direct consequence of sodium's eagerness to lose its outer electron. There are many videos online that show the reaction of sodium in water. And it's pretty violent. In fact, all Group 1 elements behave this way, and the heavier the element, the. The more reactive it becomes. Because sodium is so reactive, it's never found naturally as a free metal. Instead, it's always found in compounds, Especially salts. The most important is sodium chloride, or ordinary table salt. Despite humans having used sodium compounds for thousands of years, we had no idea that sodium was a thing or an element. The key breakthrough came in 1807, when the English chemist Humphry Davy Isolated sodium by electrolyzing molten sodium hydroxide. By passing an electric current through molten compounds, he was able to break them apart into their elemental components. In the same period, he also isolated potassium, calcium, strontium, barium, and magnesium. The name sodium is derived from the Latin word Sodanum, which refers to a headache remedy made from a sodium rich plant, while its chemical symbol is Na, comes from natrium, the Latin name used in some European languages and ultimately adopted as the official chemical symbol. Sodium is usually ranked as the sixth most abundant element in the Earth's crust by weight, after oxygen, silicon, aluminum, iron and calcium. Sodium makes up roughly 2.3 to 2.8% of the Earth's crust by weight, depending on the source and estimate. Because it can't be found in its pure form in nature, it occurs in minerals such as feldspars, rock salts and soda minerals, as well as in dissolved sodium ions in seawater. Sodium chloride, AKA table salt, is the most famous sodium compound, and I've already done an episode on the subject. However, it is far from the only important compound. Sodium hydroxide, also known as caustic soda or lye, is a powerful base used in soap making, paper production, drain cleaners and many chemical processes. Sodium carbonate, or soda ash, is used in glass making, detergents and water treatment. Sodium bicarbonate, or baking soda, is used in baking, as an antacid, in fire extinguishers and for odor control. Sodium hypochlorate is the active ingredient in many household bleaches, and sodium nitrate has been used as a fertilizer and as a preservative. Sodium compounds are everywhere because sodium ions are stable, soluble and easy to work with. And this is perhaps the biggest paradox of sodium. In its pure form, it's extremely reactive and dangerous, but as an ion, it's very stable. In nature, sodium plays several roles. Geologically, it is a part of the rock cycle and the ocean's chemistry. Sodium is weathered out of rocks, carried by rivers and eventually accumulates in seas, lakes, salt flats and evaporate deposits. In dry regions, sodium salts can accumulate in soils, sometimes causing problems for agriculture by damaging soil structure and interfering with plant growth. Biologically, sodium is essential for all animals. In humans and other animals, sodium ions help regulate fluid balance, blood volume, nerve impulses and muscle contraction. Nerve cells use sodium and potassium gradients to generate electrical signals. When a nerve impulse travels down a neuron, sodium channels start to open. Sodium ions then rush into the cell and the electrical charge changes. This is one of the basic mechanisms that allows thought, sensation, movement and your heartbeat. Sodium is also central to the body's water balance. Where sodium goes, water tends to follow. This is why sodium affects blood pressure and fluid retention. The kidneys carefully regulate sodium levels, conserving it when intake is low and excreting it when intake is high. Hormones such as aldosterone also help to control sodium levels. Humans do need sodium, but not in large amounts. Too little sodium can result in hyponatremia, a dangerous condition in which blood sodium levels fall too low. This can happen from severe illness and excessive water intake, certain medications, or extreme endurance exercise without proper electrolyte replacement. Symptoms can include headache, confusion, nausea, seizures, and in severe cases, even death. However, too much sodium, especially over long periods of time, is also a problem. High sodium intake is associated with increased blood pressure in many people, and high blood pressure raises the risk of heart disease, stroke and kidney disease. The main source of excess sodium in modern diets is usually not the salt shaker, but processed foods, restaurant meals, cured meats, soups, sauces, snacks and packaged food. In the industrial world, sodium is enormously important. The largest sodium related industry is salt itself. Sodium chloride is mined from underground deposits extracted from seawater or produced from brines. It is used for food, road de icing, water softening, animal feed and chemical manufacturing. Salt is also the starting point for the chloral alkali industry, which uses electrolysis of brine to produce chlorine gas, hydrogen gas and sodium hydroxide. These products feed into plastics, disinfectants, paper, textiles, detergents, pharmaceuticals and many other industries. One of the most promising uses for sodium is as a coolant in certain nuclear reactor designs. Once melted, it is excellent at dissipating heat from the reactor core. These are usually called sodium cooled fast reactors or SFRs. They are different from the ordinary water cooled reactors used in most commercial nuclear power plants today. In a conventional reactor, water does two jobs. It carries heat away from the core and it slows down neutrons. Slowed down neutrons are called thermal neutrons and they're very effective at sustaining fission in the kind of fuel most reactors currently use. In a sodium cooled fast reactor, the goal is different. The reactor is designed to use fast neutrons, meaning neutrons that are not slowed down very much. Sodium is useful because it transfers heat well, but it does not significantly moderate or slow neutrons. That allows the reactor to operate in a fast neutron spectrum. Fast reactors can make more complete use of uranium fuel and potentially consume plutonium and other long lived isotopes from spent nuclear fuel. Sodium has also been used in electric lighting. Sodium vapor lamps are gas discharge lamps that produce light by passing an electric current through sodium vapor. They're best known as the old yellow orange street lights that gave many roads, parking lots, tunnels and industrial areas their distinctive nighttime color. They come in two main low pressure sodium and high pressure sodium. A low pressure sodium lamp contains a discharge tube with a small amount of metallic sodium and starter gases such as neon or argon. When the lamp first turns on, the starter gases glow reddish or pink. As the lamp warms up, the sodium vaporizes and the light shifts to a very strong yellow orange. That weakness, the color, was also part of its strength. Low pressure sodium lamps were extremely efficient. They produced a lot of visible light for each watt of electricity, making them attractive for street lighting, highways, security lights, ports and industrial yards. Sodium lamps began being used widely for street lighting beginning in the 1930s along largely because of their efficiency and because their yellow light performed well in fog. A high pressure sodium lamp works on the same basic principle, but under higher pressure and temperature. Its arc tube is commonly made from translucent alumina because hot sodium is chemically aggressive and would attack ordinary glass. High pressure sodium lamps also often contain mercury and other materials that broaden the spectrum. The result is still yellow, orange, but not as bad as low pressure sodium lamps. While sodium vapor lights were very popular during the 20th century, they've been disappearing rapidly over the last several decades. And the reason is actually pretty simple. The yellow light from sodium vapor lamps was tolerable because they were so power efficient. LED street lights, on the other hand, use even less energy, last longer, switch on instantly, work well with dimming and smart controls, and can provide a more natural color. The shift from sodium vapor to LED streetlights has dramatically changed what many cities look like at night. An aerial image of Chicago at night taken in the 1990s shows a massive yellow grid. That same photo taken today is now a completely different color. Finally, metallic sodium is useful for removing reactive elements such as oxygen, chlorine, sulfur, and other non metals from a compound. One particular application is the purification of metal. When titanium tetrachloride is exposed to metallic sodium, the sodium will strip away the chlorine, leaving metallic titanium behind. Likewise, if you took some metal oxide, such as iron oxide, AKA rust, the sodium could strip away the oxygen, leaving behind a pure metal and sodium oxide, also known as soda. Sodium, as an element is not rare, exotic or glamorous, but it is one of the truly foundational elements of civilization. The oceans are full of it, our bodies need it, it's found in our kitchens, and it might even have great use in nuclear reactors in the future. Yet there are problems with consuming too much or too little of it. And in its elemental metallic form, it can be extremely dangerous. And all of these things are true simultaneously due to the dual nature of sodium. The executive producer of everything Everywhere Daily is Charles Daniel. The associate producers are Austin Otkin and Cameron Kiefer. My big thanks go to everyone who supports the show over on Patreon. Your support helps make this podcast possible, and I also want to remind everyone about the community groups on Facebook and Discord. That's where everything happens that's outside the podcast, and links to those are available in the show notes. 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