Tungsten is a mind-bending material. Nothing about it is ho-hum. It's one of nature's most breathtaking creations and a virtually ignored part of modern life. Below, I've assembled some of tungsten's most interesting factoids. Read them, sure, but more importantly, look on this as a small illumination of the previously unknown. Specifically, if all the really cool stuff on this page is new and it's about a material that's been around you since you were born, what other incredible things lie in store for those curious enough to look?
Tungsten is one of the foundation elements of our civilization–right up there with iron (structures) and silicon (computers). Tungsten lightbulb filaments have lit the lives of every person on the earth. Without them we would literally be "in the dark." Despite the relatively recent development of just-bearable fluorescent lights there's likely to be more hot tungsten in our lives owing to an ultra-efficient new light technology that uses photonic crystals of tungsten. Tungsten has the highest melting and boiling points of any element, 3420°C (6200°F) and 5700°C (10300 °F). If you could transport a piece to the surface of the sun, it would actually be a liquid. Put another way: if you accidently dropped your BOMApen from the space shuttle, it would probably hit the Earth ("Whoops!").
How can one comprehend such high temperatures? Try this: Most ovens operate at a maximum of 500°F–about 400 to 450°F above room temperature. So achieving the melting point of tungsten would require putting one oven inside another oven, inside another oven, inside another oven...and so on for a total of thirteen ovens and turning them all on to their highest setting. If you tried this with real ovens somehow sized to fit one within the other like this, all the copper would melt starting with the fifth oven in and all the steel would melt starting with the 7th oven in. Only a few ceramic parts MIGHT make it to the thirteenth oven.
Since 1912, Tungsten (the element or, perhaps, an uncle) has been widely used to make the most essential part of any lightbulb–the filament. BOMApens have the tungsten content of 3000 to 6000 one hundred watt light bulbs, depending on model and configuration. Many fluorescent lights make use of the fluorescent materials, Calcium and Magnesium Tungstate. Tungsten is quite dense. A cup of water weighs 8 ounces. A cup of tungsten weighs almost 9 POUNDS. Water's density is exactly 1 gram per cubic centimeter. Tungsten's density is usually agreed to be 19.35 g/cc. This is HIGH density–well outside the range of normal experience. For scale, consider that both granite and aluminum have a density of only about 2.7 g/cc. So Tungsten is SEVEN times denser than stone! Other common dense materials just don't compare:
- Most iron and steel have density right around 8 g/cc–less than half the density of tungsten.
- Lead has a density of 11.3 g/cc–about 40% lower than Tungsten
- Both Lead and steel float on Mercury, with a density of 13.6 g/cc–about 30% lower than Tungsten
Tungsten carbide–the same material your pen is surfaced with–is extremely hard and durable. It's the material of first choice in cutting tool bits from machine shops to mines to oil drilling rigs. The technology of making metal cutting toolbits out of tungsten carbide was first developed by German researchers in 1922. In 1927 modern toolbits using cemented carbide (cermets) were invented. It was one of the technological underpinnings of the Nazi's ability to mass produce high precision weapons of war. For a metal, Tungsten is remarkably stiff and rigid—fully twice as rigid as steel, almost four times stiffer than titanium, six times stiffer than aluminum and about 100X stiffer than plastics. This property allows the manufacture of very rigid machine tools. Tungsten alloy tool holders are considered THE premier holders and command amazingly high prices. Tungsten makes excellent X-ray and gamma-ray shielding. It's a half again better than lead by thickness. This, plus its strength and biocompatability, make it idea for medical equipment designed to deliver radiation with pinpoint accuracy and little exposure to surrounding tissues. Infact,
Tungsten was recently chosen as the material of choice for a revolutionary new pinhole X-ray camera. The term “heavy metal" poisoning is a name sometimes used to describe poisoning by lead (density 11.3 g/cc), cadmium (8.7 g/cc) or mercury (13.6 g/cc). These elements are really only marginally heavy. Really heavy elements that you might someday have occasion to come into contact with, like Gold (19.3 g/cc), Platinum (21.5 g/cc), Tungsten and Tantalum (16.4 g/cc) are also extremely safe. Extremely fine, pure tungsten wire has the distinction of being the strongest material in the world. Even more astounding is that this was discovered in the 1920's. It's tensile strength hits a whopping 600,000psi; beating out such modern high tech materials as boron fiber (~500,000 psi), carbon fiber (350,000 to 450,000 psi) and ultra-high tensile music wire (400,000 to 575,000 psi). Who would have guessed that the very same material that delicate and fragile lightbulb filaments are made from is used to smash through tank armor? Armor piercing projectiles made of tungsten are well know to the militant world. Considering the popular alternative is depleted uranium, a highly poisonous material, tungsten once again is the good guy...or something. Bullets and buckshot have traditionally been made from lead–one of the most perniciously toxic materials in everyday use. So rather than continuing to spray it indiscriminately all over the planet, a composite material containing tungsten has been developed. It's just catching on. The earth is 4 billion years old, sure, but how long did it take for the core to form? Ask tungsten. A new study pins the formation of the core as occurring during the first 30 million years. Rather clever scientists have figured this out by analyzing the amount of tungsten 182 in the earth's mantle. The reasoning goes like this: tungsten 182 is only produced as a decay product of hafnium 182. Any and all of the tungsten on the early (not-solid) earth would have sunk into the core because of it's high density and because it doesn't readily incorporate into minerals. Hafnium, being chemically similar to titanium, would have been easily locked into relatively lightweight minerals and would have stayed on the outside as soon as there was an outside–when the mantle started forming, covering the core and presumedly ending the core's independent formation. So all the tungsten 182 that we have access to came from hafnium built into the mantle. Comparing the abundance of tungsten 182 in the mantle to its abundance in a non-cored object like an asteroid gives a mantle deficit of tungsten 182 that can be accounted for by 30 million years of core formation. Whew!
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Level One: The pens and an introduction to their features