MetaFilter posts tagged with Chemistry

That's funny, Joey, I don't smell anything

escabeche — Thu, 09 May 2013 05:47:16 -0800

"The memory is stil with me - the most sickly and sweetish smell of rancid gasoline combined with rotten water melons, with undertones of stale sweat, pig carcass, a hint of garlic, moldy oranges, russian-made aftershave and a cheap household air freshener… its a whole package, and rather sweet one – like isonitriles or cyclopentadiene but magnified thousand times. A whiff of that thing and you feel that your nose just suffered a stroke and will hopefully die and peal off so that you never smell that thing again." A young lab tech, whose absent-mindedness in the lab gets him nicknamed "“Bořivoj” (”the one who tears down the places”), meets PhePHMe, the worst-smelling compound in the world. Things happen.

"it was even thicker than planned, for a brief exciting interlude"

the man of twists and turns — Sat, 23 Mar 2013 09:56:39 -0800

How Not To Do It: Chromium Trioxide

Back in grad school, I had an undergraduate assistant one summer, a guy who was pretty green. I'll refer to him by an altered form of his nickname, henceforth as Toxic Jim. I shouldn't be too hard on him, I guess: I was a summer undergrad in my time, too, and I wasn't a lot of help to anyone, either. But TJ did manage to furnish me with some of my more vivid lab stories in his brief time in my fume hood. One morning I showed him how to make PCC. That's pyridinium chlorochromate for the non-organic chemists out there, an oxidizing agent that doesn't seem to be used as much as it was 15 or 20 years ago. Even in '85, you could buy it, but the freshly-made stuff was often better. It certainly looked nicer. Like all the Cr(VI) salts, it has a vivid color, in this case a flaming orange. I shouldn't say "flaming;" that's getting ahead of the story. . .

Those Atoms are Mighty Fuzzy

Leezie — Fri, 08 Mar 2013 18:16:51 -0800

16 Golden Retrievers teach all about atoms. SYTL I for one would have probably done much better in chemistry if had been explained this way.

An Elegant Weapon For A Less Civilized Age

Pirate-Bartender-Zombie-Monkey — Wed, 06 Mar 2013 12:39:11 -0800

They were the finest European swords the day, superior to almost any other on the battlefields of the Viking Age. Made from steel no one in Europe would know how to make until the Industrial Revolution. Stronger, more flexible, almost magical in combat, engraved with the mysterious name "+ULFBERH+T" by unknown makers, these swords were the both fearsome weapons and incredibly expensive prestige possessions. Only 171 have every been identified. And no one had made one from start to finish, using only hand tools, for over 900 years. The "Ulfberht" swords were viking swords made between ~800 and 1100 C.E. of crucible steel. Crucible steel is made by heating iron ore with a source of carbon (often charcoal or bone) close to 3000°F until almost all the impurities ("slag") are removed from the iron and the carbon is absorbed, leaving a purer steel. The technique for crucible steel was unknown in Northern Europe at the time the Ulfberht Swords were forged, but it was known in places like Afghanistan and Iran. By the Viking Age, warriors to the East had been fighting with superior weapons made of Damascus Steel for centuries. The theory is that Viking traders plying the Volga Trade Route brought back crucible steel ingots. When the Volga Trade Route was closed by the Russians around the 12th century, the making of Ulfberht swords ceased. Swords in general were prized possessions to the vikings, as most warriors would be armed with spears and axes. Any sword was a much greater investment in time and materials, and the crucible steel of the Ulberhts made them sharper and (importantly) less likely to chip and break in battle like swords made of lower-grade steel. In a testament to how good the Ulfberht swords were, people went to the trouble of making fakes of lower-quality steel with the Ulfberht brand name on them. And as is usual with brand-name fakes, the details matter. The name "Ulfberht" is not Norse, it's Frankish. Also, the two "+" in "+ULFBERH+T" would, in that age, have been associated with a Bishop's name, or someone else in the Church hierarchy. And Christians (as the Franks were since Clovis I) were forbidden from trading with the Pagan vikings. But Church armorers would not have access to crucible steel from the East like the vikings, so the mystery of the name reamins unsolved. PBS site

Pepto Bismuth

dhruva — Sun, 03 Mar 2013 16:07:04 -0800

The chemical process of isolating bismuth metal from Pepto Bismol.

Sense About Science

Blasdelb — Thu, 28 Feb 2013 07:08:22 -0800

With a database of over 5,000 scientists, from Nobel prize winners to postdocs and PhD students, Sense About Science works in partnership with scientific bodies, research publishers, policy makers, the public and the media, to change public discussions about science and evidence. They make these scientists available for questions from civic organizations and the public looking for scientific advice from experts, campaign for the promotion of scientific principles in public policy, and publish neat guides to understanding science intended for laypeople. These are pretty neat guides, basic enough to be accessible to most anyone but also in-depth enough that even knowledgable laypeople can expect to learn something new, The Making Sense Of series:

Making sense of Statistics [PDF] This guide is not a lesson in statistics. It provides the questions to ask and identifies the pitfalls to avoid to help us get behind news stories that use statistics. But when confronted with stories such as “Diabetes drug raises death risk by 60pc”, “Gender pay gap still as high as 50%” and “Polls puts Tories up to 7% ahead”, how can we work out whether to believe them and what they really mean? Dismissing all statistics as just ‘lies’ does not help us get to grips with a story. By working through the points in the guide we can work out what the figures might be telling us. Making Sense of Testing [PDF] Why scans and health tests for well people aren't always a good idea. Adverts and media reports say that people with no symptoms, nor reason to suspect they have a disease can find out what they will get in the future, “reverse the disease processes before symptoms appear”, or even discover how they will die. People are promised instant results, valuable insights and ‘peace of mind’. What many people are getting is a lot of confusion and anxiety, ongoing trips to the doctor and, sometimes, unnecessary medical procedures. The guide presents a few insights and highlights common misconceptions about having health tests and scans. Making Sense of Screening [PDF] A guide to weighing up the benefits and harms of health screening programmes Public expectations about screening don't match what screening programmes can deliver. By addressing misconceptions about how screening works, its limitations and the calculation of benefits and harms, scientists and clinicians hope to bridge the gap between the active debates of the scientific community and the concerns raised by the public. Making Sense of Radiation [PDF] A guide to radiation and its health effects Many people have become anxious about exposure to non-ionising forms of radiation, from mobiles, Wi-Fi and masts. Together with scientists, engineers and medical professionals we identified some of the tools and insights that they themselves rely on to help deliver a clearer picture of what radiation is, what it does and what it can't do. Making Sense of Chemical Stories [PDF] A briefing document for the lifestyle sector on misconceptions about chemicals. The guide flags up the more serious misconceptions that exist around chemicals and suggests straightforward ways to evaluate them. It is intended to open a conversation that promotes a stronger connection between lifestyle commentary and chemical realities. Making Sense of GM [PDF] What is the genetic modification of plants and why are scientists doing it? The guide examines how GM has been debated in the past and presents commentary from scientists and agriculturalists. They respond to the public's questions and misconceptions and put GM into the context of developing plant breeding. Making Sense of Weather and Climate [PDF] An introduction to forecasts and predictions of weather events and climate change We worked with climate and weather scientists to review how weather and climate issues are discussed in media coverage and policy debates. This briefing addresses what they noticed were frequent misunderstandings to avoid losing sight of the science amidst the rows about policy, the exaggeration and Hollywood-style presentation.

Other Guides

I've Got Nothing to Lose by Trying It [PDF] A guide to weighing up claims about cures and treatments I Don't Know What to Believe [PDF], US version [PDF] Making sense of science stories This leaflet is for people who follow debates about science and medicine in the news. It explains how scientists present and judge research and how you can ask questions of the scientific information presented to you. Peer Review and the Acceptance of New Scientific Ideas [PDF] Discussion paper from a Working Party on equipping the public with an understanding of peer review.

Culinary Tech

lemuring — Tue, 26 Feb 2013 12:10:23 -0800

Polyscience is a company at the cutting edge of culinary technology. [Previously]

"...it's always good for a scientist to be proven wrong..."

loquacious — Fri, 11 Jan 2013 04:37:39 -0800

Professor Martyn Poliakoff of Periodic Table Videos fame learns something about burning balloons full of hydrogen via high speed camera footage.

Operation Delirium

homunculus — Mon, 10 Dec 2012 13:05:00 -0800

Operation Delirium. "The military’s secret Cold War experiment to fight enemies with clouds of psychochemicals. Decades after a risky Cold War experiment, a scientist lives with secrets." [Via]

"This post, dear reader, is 100% about cats."

beryllium — Wed, 05 Dec 2012 11:31:05 -0800

Screw organic chemistry, I'm just going to write about cats. James Ashenhurst uses (sometimes highly unorthodox!) cat pictures to explain topics in stereocatmistry, starting with On Cats, Part 1: Conformations and Configurations. The full series: On Cats, Part 2: Cat Line Diagrams On Cats, Part 3: Newman Projections On Cats, Part 4: Enantiocats On Cats, Part 5: Enantiocats vs. Diastereocats On Cats, Part 6: Stereocenters On Cats, Part 7: The Fischer Projection On Cats, Part 8: Moe the Meso Cat

The rain in Spain smells mainly of dimethyl-9-decalol

mrgrimm — Wed, 28 Nov 2012 09:48:21 -0800

The smell of earth after rain is called Petri chor, and it is caused by Geosmin, a sesquiterpenoid metabolite with the chemical formula C₁₂H₂₂O. Human sensitivity to geosmin is about 10 parts per trillion. (via)

Could I interest you in dessert?

madamjujujive — Mon, 26 Nov 2012 17:57:28 -0800

Chef Grant Achatz plates the final dessert course at Alinea. Or perhaps you'd prefer the chocolate pumpkin pie or the edible balloon? Bon appetit!

What's gonna happen outside the window next?

cthuljew — Sun, 18 Nov 2012 13:51:19 -0800

Noam Chomsky on Where Artificial Intelligence Went Wrong

The Chem Coach Carnival

Orange Pamplemousse — Wed, 31 Oct 2012 07:24:49 -0800

What do chemists do in a "work day"? What kind of schooling do they have? How does chemistry inform their work? Do chemists have any funny stories to tell? Last week chemist See Are Ohh* was wondering what a chemistry life coach would look like. So, he started a blog carnival in honour of Mole day, with fifty-nine chemists chiming in to share their experiences and offer advice to budding scientists. Announcement, Day 1, Day 2, Day 3, Day 4, Day 5, Day 6, Wrapup. *CRO, contract research organization.

2H2O2 → 2H2O(l) + O2(g)

growabrain — Fri, 26 Oct 2012 13:45:58 -0800

What do you get when you mix hydrogen peroxide, iodine and dishsoap? Elephant's Toothpaste (or Elefantenzahnpasta, if you prefer German). Many more class experiments from the 2nd link here. Wiki explanation: "Concentrated hydrogen peroxide is first mixed with liquid soap. Then a catalyst is added to make the hydrogen peroxide break down very quickly. Hydrogen peroxide breaks down into oxygen and water. As a small amount of hydrogen peroxide generates a large volume of oxygen, the oxygen quickly pushes out of the container. The soapy water traps the oxygen, creating bubbles, and turns into foam. Often some food coloring is added before the catalyst, which makes the resulting column of foam look even more like toothpaste."

Recommended laboratory procedures

catlet — Tue, 25 Sep 2012 20:03:06 -0800

Thousands of drug-related convictions in Massachusetts may be challenged as investigators learn more about improper evidence handling and testing at a Department of Public Health laboratory. Over 50,000 samples related to 34,000 convictions were tested by a single chemist at the lab, who is alleged to have violated multiple laboratory protocols. Governor Deval Patrick's office has identified 1,141 inmates currently serving time in Massachusetts whose convictions may be affected by the investigation. The chemist, Annie Dookhan, is alleged to have mixed samples from unrelated cases, broken the chain of evidence, and altered the weight of samples. Today, the Department of Public Health announced that Dookhan had claimed a master's degree in chemistry, but never enrolled in graduate study. While under oath in 2010, Dookhan claimed that she was responsible for the lab's overall quality control, which may open the door to challenges against cases in which she did not directly test evidence. Doubt about the validity of drug test results has already had an effect on Massachusetts judges.

Ben Krasnow builds neat things.

joechip — Mon, 24 Sep 2012 11:27:48 -0800

Ben Krasnow shows us how he built a small hybrid rocket engine. Ben makes a lot of other cool things too, like astronaut ice cream, a DIY scanning electron microscope, and why not, carbonated fruit slices.

Burning Mercury Thiocyanide Will Amaze You

shivohum — Sun, 23 Sep 2012 23:14:17 -0800

Burning Mercury Thiocyanide Will Amaze You (SLYT)

"We didn't ask, 'Are you seeing monsters and aliens?' They were telling us that."

zjacreman — Fri, 21 Sep 2012 11:02:50 -0800

PBS Newshour brings the science on bath salts (previously). Contains graphic descriptions of awesome laboratory experiments. via BoingBoing

A Tall Tail

brundlefly — Sat, 21 Jul 2012 16:43:14 -0800

"A Tall Tail," by MeFi's own Charles Stross.

For SCIENCE!

Bora Horza Gobuchul — Fri, 13 Jul 2012 20:15:59 -0800

Science for the people: take a renowned scientist (Nobel Laureate Leon Lederman (Physics), Stephen Benkovik (Chemisty)) and sit them down on a street corner to answer questions.
Also: The No Excuse List (resources to learn just about anything), Minute Physics, Udacity (free, University-level courses online) and PetriDish, a Kickstarter for science projects.