Every year around Halloween, we hear the same concern: you gotta check the candy for poison because strangers put laxatives in Tootsie Rolls, Razor Blades in Apples and drugs in Snickers.
The truth is out there.
Mischmetal
You’ve seen this metal mixture in action before in movies. It’s used on film sets when two swords clash in a fight or when a car grinds against a metal rail during a car chase. The mixture of 35% lanthanum, 63% cerium, and smaller percentages of neodymium, praseodymium, iron, and magnesium is called mischemetal, and it produces showers of bright white sparks when struck with an abrasive object or scratched with a blade. Cerium is the main element responsible for the sparks because it oxidizes rapidly when exposed to air. A large piece of cerium–or a cerium alloy such as mischmetal–forms a passivating oxide layer that protects the bulk of the metal. But striking the metal liberates tiny pieces with exposed cerium metal surfaces that react with oxygen in the air, get hot, and glow.
Credit: Andres Tretiakov @Andrestrujado/ezgif.com
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Quest for the golden flask
The solid coating this round-bottom flask isn’t actually gold, but it could prove valuable one day. Jan Griwatz, a graduate student at Justus Liebig University Giessen, made the compound, 6,7-dimethyl-1,4-naphthoquinone (structure shown), as the first step in a new synthesis of materials that could be used in flow batteries—energy storage devices with enough capacity to power several houses. Effective flow batteries could store solar and wind energy for use after the sun goes down or the wind stops blowing. From this molecular building block, Griwatz hopes to quickly make several varieties of anthraquinone materials and see which work best in flow battery applications.
Submitted by Jan Griwatz
More Chemistry in Pictures and C&EN stories:
If you’re curious about where it all comes from, then this is the show for you. Each week on YouTube and Facebook, host Danielle Bainbridge will give you the perfect dose of weird history. Scary clowns, cannibals, hashtags, national healthcare system, memes, you name it!
The fun starts on Tuesday September 5th. Reblog if you’re as excited as we are!
When did clowns get so terrifying?!?
Well, sure the answer is partly from 1980s horror movies like IT and Killer Klowns from Outer Space, but the reality is much deeper than that. From the Middle Ages through the Renaissance to 19th Century England, clowns have always been around to bring a little chaos.
A refractory ceramic material with a high melting point (over 2200C), lanthanum hexaboride, or LaB6, is a naturally purple-violet ceramic when the samples are stoichiometric, though boron-rich varieties are blue.
Insoluble in water and hydrochloric acid, lanthanum hexaboride’s most valuable properties are its low work function and high electron emissivity, as well as its ability to be stable in vacuum. The work function is loosely defined as the minimum energy needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface, which makes LaB6 an ideal material in applications that require loose electrons.
Because of these properties, LaB6 is mainly used as a hot cathode, often in the form of single crystals or as coatings. These hot cathodes are used in electron microscopes, microwave tubes, electron beam welding, and more. While tungsten filaments are often also used for these applications, LaB6 is many times “brighter” (has a higher current density) and has a much longer lifetime. Similarly, other hexaborides (such as cerium hexaboride) also have low work functions, and are occasionally used as well in these applications. Another application for LaB6 includes as a standard for x-ray powder diffraction to calibrate diffraction peaks.
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A fundamental issue that needs to be addressed is young people’s perceptions of STEM subjects. The disinterest in science and technology fields starts very young; all you have to do is look at the media children consume. Science-related characters are often portrayed as geeky or nerdy, and are almost always male. Instantly this implies that science is not a subject for girls, and children who are interested in science don’t necessarily see it as a positive trait. We are limiting our young people by not showing them what they could be and encouraging them to follow any passions they may have.
I, your tumblr mod and Reactions writer, will be doing an AMA at about 1-2pm EDT today about science writing, podcasting, and scicomm careers. Feel free to drop me a question.
materialsscienceandengineering
materialsscienceandengineering
Any glass that includes uranium can be classified as a uranium glass, of which there are many varieties: vaseline glass, Depression glass, custard glass, Burmese glass, and jadite glass, among others. The uranium content is typically around 2% or lower, but there are some glasses out there containing as much as 25%. The uranium is typically added in the form of uranium dioxide.
Uranium glass, and Vaseline glass, is transparent and yellow to yellow-green, though other colors can be achieved with the addition of further colorants. In the 1800s vaseline glass was known as canary glass and the term vaseline dates from the 1900s because of its similar color to the well-known petroleum jelly. Depression glass is so called because it was produced largely during the Great Depression, and was typically of poor quality even while coming in a variety of colorful patterns. Most, but not all, Depression glass is uranium glass.
Burmese, custard, and jadite glass are all typically opaque forms of uranium glass, but the terms are largely used to differentiate between the appearance or color, not the uranium content of the glass. They can range in color from shades of pale yellow to green to pink.
Because these types of glass contain uranium, they are radioactive, and will typically fluoresce with a rich green color under UV light (though the radioactivity doesn’t cause the fluorescence - the chemistry of uranium does). Uranium is used in glass not for the properties it grants the final product, but solely as a colorant. Its radioactivity typically will register on sensitive Geiger counters, but is considered harmless and is lower than the typical amount of radiation that one encounters throughout everyday life.
Most popular from the 1880s to the 1920s, uranium glass slowed in production between the 1940s and 1990s not because of its radioactivity, but because uranium was increasingly difficult to obtain during the Cold War. While dinnerware was a common use of uranium glass, today the few companies that still produce it only make decorative pieces. Another applications of the material was in glass-to-metal seals, thanks to its favorable coefficient of thermal expansion.
Sources: ( 1 - images 1 and 3 ) ( 2 - image 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 )
Image source: ( Image 4 )
