This week’s Chemistry in its element podcast is a must for all chocolate lovers as Brian Clegg gives us a taste of theobromine: the food of the gods that’s bad news for dogs.
Chemistry in its element – theobromine
Category Archives: Chemistry
London Centre for Nanotechnology
The other day I got out of the office and went to poke around the London Centre for Nanotechnology’s labs at Imperial College London. It’s always great to meet people and put faces to names, but it’s also sometimes really helpful to actually see the equipment that’s used. It’s all very well to read about pulsed laser deposition, for example, but it’s another thing entirely to nose around the HUGE piece of kit that is actually used to do it. Sometimes it seems like you need even bigger equipment as you start working at smaller scales.
— Titan Microscope
About half of what you can see is the aberration correction section that allows such good resolution
OK, that’s a bit of a generalisation maybe. But the TITAN microscope, with its aberration correction,shows that to get true atomic resolution, the equipment needs to be even bigger than before. But although the kit that corrects for the spherical symmetry of the lenses adds to the height of the microscope, it means you can see brilliantly sharp images of crystal lattices and interfaces, or where metal nanoparticles end up in cells.
I also had a real brain work out looking at the work being done on magnetic monopoles in synthetic spin ices, that made me realise that sometimes the simple things you take for granted are the things you really don’t understand at all. Essentially these monopoles can jump around the lattice much like electrons on a semiconductor, or at least that’s how I’ve come to terms with it in my brain. Currently though, these phenomena aren’t very well understood and only happen at very low (sub 10K) temperatures, but could lead to spintronics and molecular memory devices. So, a bit more complex than the shaking iron filings around a bar magnet.
The real fun came a bit later though, when I got to play with the Emisense liquid scanner. I’m sure we’re all frustrated with the small amount of liquids that we’re allowed to take in hand luggage and loads of people are working on ways to test liquids when you go through security. Personally though, I don’t really want anyone opening up my water and sticking probes or dip sticks inside. Ideally you need a scanner that works at about the same speed as the trundling x-ray scanner that checks your suitcase for nail files. The EMILI 2 uses an evanescent microwave field to identify liquids using dielectric permittivity, molecular relaxation and ionic conductivity. More importantly it does this quickly (within a second of you putting ta bottle on the scanner) and gives a simple yes/no readout, as you can see below.
— Emisense
Water good, peroxide bad
We’ll have to wait and see whether this makes it to an airport near you, but if it does you can say you saw it here first.
Laura Howes
Mr. Lee – Chemistry rap – Video
21-01-2011 21:48 A song about the basics of chemistry for my eighth graders, sung to the tune of "Fire Flame" by Birdman ft.
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Mr. Lee - Chemistry rap - Video
Will Sheri Sangji’s death change safety culture?
Sheri Sangji (Courtesy of Naveen Sangji)
Developments in the case of Sheharbano (Sheri) Sangji’s death at UCLA in 2009 have been dominating the chemistry news for the last week or so. With the University of California and Sangji’s supervisor Patrick Harran facing criminal charges relating to their management of their health and safety obligations.
The detailed twists and turns of the case have been doggedly covered by Jyllian Kemsley over at Chemical & Engineering News, and debate online over where responsibility lies and what the problems were has been voracious.
Sangji’s is the most serious of a series of high-profile incidents, including explosions at the University of Liverpool, UK, and one at Texas Tech University, US, where a student lost three fingers and perforated an eye among a list of other injuries. This prompted the US Chemical Safety Board to investigate the incident and their report paints a stark picture of safety at TTU (which by all accounts has improved significantly since). The case study also includes anecdotal evidence from 120 other incidents, suggesting a more widespread issue.
Here at Chemistry World, we wanted to examine what it takes to make laboratory environments safer, and what differences there are between the US and the UK and elsewhere. You can read my story here, but we wanted to take the opportunity to ask you, our readers, what you think:
What is the safety culture like in your institution, or others you’ve worked in?
Has anything changed since these incidents? Do you think it will?
Having spent a few years in a synthetic chemistry lab myself, as well as stints in industry, I’ve come across my fair share of minor incidents, both at my own bench and at colleagues’. I also saw the difference between attitudes to safety at two UK universities. Personally, I hope that our laboratories can become safer places to work, but there are not going to be any quick fixes. We all need to take responsibility for safety – after all, understanding safety comes down to understanding chemistry. If you know the risks involved with what you’re doing, you can take steps to manage them, just like when you drive a car or cross a road.
One of the clearest messages that came back to me from talking to several health and safety professionals in researching my story was that no one wants to stop anyone doing research. If it’s done right, health and safety management should enable researchers to do the work they need to, but in an appropriate environment. So again, let us know what you think – does this happen where you are?
Phillip Broadwith
The science behind Marks & Spencer’s fruit packaging
— Red strawberry
Ground breaking packaging news has reached CW Towers, British retailer Marks & Spencer is launching new packaging to extend the life of strawberries. The store, whose food adverts have become much copied in recent years, say their new packaging will extend the life of fruit stored in the fridge by up to two days. So these are not just any berries, these are M&S berries, but why?
The packaging apparently uses a 8cm x 4.5cm strip that contains ‘a patented mixture of clay and other minerals that absorb ethylene‘. Ethylene, or as we chemists tend to refer to it, ethene, is the smallest possible alkene and a well known plant hormone involved in the ripening of fruit. It’s why the trick of putting a ripe banana in a bag with unripe fruit will ripen it. I haven’t found the patent from the firm involved, but we can make some educated guesses about how this works. Clay is an aluminosilicate with a large volume, so perhaps what we’re talking about something akin to a zeolite, with a large surface area for the gaseous ethene to adsorb onto. And as for the other minerals, perhaps the pores are impregnated with some antibacterial agent, like silver, to keep the fruit extra fresh. That’d be my guess.
But I can’t help thinking this is of more use to the store itself, for preventing fruit spoilage on the shelves. I certainly don’t tend to take strawberries home and stick them in the fridge, I wash them and put them in the fruit bowl, or just eat them all at once and I doubt I’m the only one. But maybe I am, would this help you?
If you want to read more about how chemistry is being used in packaging, check out this feature that Nina wrote in 2009, as well as searching for more recent news articles.
Laura Howes
Quasicrystals from space
— A rock sample from the mineral collection of the Museo di Storia Naturale in Florence previously unearthed in the Koryak Mountains in Russia. © P Steinhardt
Not quite an alien invasion of cinematic proportions, but pretty cool none the less. As hinted at in my feature last year, Paul Steinhardt has shown that the only natural example of a quasicrystal ever discovered comes from space.
In 2009 Steinhardt was part of a team that looked through sample after sample for a natural example of a quasicrystal before finding one in a rock from north-eastern Russia. However, as Steinhardt told me last year, the discovery was not universally believed. That led to the theoretical physicist kitting up and heading into the field to try and find more examples. But as well as looking at other rocks (which aren’t discussed in this paper), Steinhardt’s also been looking more closely at the original and, to date, only rock containing a natural quasicrystal. And his findings? They come from space.
The isotopic ratios of oxygen around the quasicrystal grain are typical of carbonaceous chondrite meteorites, suggesting that while the first quasicrystal was identified in 1982, the first quasicrystal was made around 4.5 million years before. This makes the mineral one of the earliest around. Pretty cool.
The work is published in PNAS, 2012, DOI: 10.1073/pnas.1111115109 and is open access.
Laura Howes
Chemistry in its element – neuraminic acid
The flu season is soon to be at its peak, but just how does the flu get into you? In this week’s Chemistry in its element podcast, Josh Howgego tells the sugar-coated tale of neuraminic acid and the role it has to play in the fight against flu.
One (nano) ring to rule them all
OK, it’s not quite forged in Mount Doom but this tiny ring caught my eye today. A full 22nm in diameter, it’s made using a tobacco mosaic virus coat protein as a template. The ring self assembles from solution, with 10 nanoparticles interacting with arginine residues on the outside edge of the protein. Each nanoparticle is between 3.5 and 5nm in diamter, which equates (if I’m still able to do basic maths correctly) to around 6 x 10-19g of gold, or, at today’s prices, £2.17 x 10-17, possibly the cheapest bit of jewellery ever!
Or perhaps not, as I imagine the manufacturing costs and overheads are a bit higher than an ordinary jeweller’s.
So why bother? Well gold rings of this size are predicted to have interesting optical properties, and perhaps even have negative optical permeability or refractive index, which could have amazing applications. But how do you know if you can’t make them? And make them easily.
In the meantime, we in the office will just keep making bad Lord of the Rings based puns.
The research is published in Nano Letters, DOI: 10.1021/nl203368v.
Laura Howes
[OPEN COLLAB] Contagious Chemistry. – Video
- READ READ READ READ READ READ READ -- Okay so since Winter Break is here why not have a collab? :]. Comment the part you want and I'll tell you whether or not the part is taken.
While we’re away
— A cracker of a show…
We wish you all a happy holiday and will see you in the new year, but if you find yourself missing out on your daily dose of chemistry we recommend you tune into BBC Radio 5 live on Thursday the 29th between 7 and 10 pm (UK time).
The Naked Scientists‘ Chris Smith, who you’ll know from our podcasts, will be hosting a Cocktail Party from his house (yes, really – we’ve seen the cables currently stored in his spare room) including Darcy O’Neil, a cocktail chemist who spoke to Hayley Birch last year for her feature on cocktails. They’ll also be discussing the chemistry of cooking, as well as finding out live on air if a chocolate teapot really is useless and whether bread does always land butter side down, along with answering 5 live listeners’ science questions. You can find out more here.
Following Chris will be Maggie Philbin with a show called The World Tomorrow, not that different from the name of the TV show Philbin used to present…
The press release for the whole night, with more details about the scientists taking part can be read at the BBC’s media centre site.
I’ll be adding this to my list of Christmas listening/viewing, along with the RI Christmas lectures, Dr Who and, ahem, Downton Abbey…
Laura Howes
Science tricks for the Christmas table
Do your festive dinners need spicing up?
Fancy some science tricks to wow the guests around the Christmas dinner table with? Chemistry World has put together a small collection of videos that should help keep the kiddywinks quiet, wake up the snoozers and amuse even the more cynical table guests. If you like them let us know and if you have other tricks and experiments to share then tweet us or leave us a comment.
First up, the ever reliable Richard Wiseman of Quirkology fame. He’s put together 10 interesting table top challenges and tricks, including a tea bag rocket – don’t set fire to the curtains!
The next set of videos include a number of tricks and interesting scientific phenomena tailored for children, with simple explanations of exactly what’s going on.
And here’s another video from Richard with another 10 tricks including creating a fire extinguisher from baking soda and vinegar.
And if you’ve got any sticky tape or sugar left over, why not check out the phenomenon of triboluminescence, whereby light is emmitted when a material is pulled apart, ripped, scratched, crushed or rubbed? The phenomenon is still not completely understood but is thought to be due to electrical charges being separated and then recombining, with an electrical discharge.
Finally, one more from the prolific Dr Wiseman where he uses just milk, food colours and soap to produce dynamic colourful patterns reminiscent of the beautiful Belousov-Zhabotinsky reactions (video at bottom of the page).
Why not also check out our blog on that perennial Christmas table favourite the crystal tree and the chemistry behind it. There’s further Christmas themed blogs to be found here, where you can learn why snowflakes have six points, what linked Faraday with candles and what exactly are frankincense and myrrh. Happy Christmas and new year from all at Chemistry World!
Patrick Walter
Reggae reggae source
Here’s a quirky fact straight from the Journal of Environmental Monitoring. It turns out that a major river polluter in Sweden is the Uppsala Reggae Festival!
Over three days each August, 10,000 reggae-lovers converge on the shores of the River Fyris in Uppsala. Sounds like fun for the festival-goers, but not so much for the fish. You see, at the first sign of rain the contents of the
urine soaked festival field get washed into the river (toilet facilities can’t be all that good). If that wasn’t bad enough, any drugs taken by festival-goers (lots of painkillers) are excreted in their urine and end up in the river too. And these biologically active compounds have been known to have an adverse effect on aquatic organisms.
The festival can lead to ammonium levels in the nearby river increasing 210-fold
Tests showed that the festival can temporarily result in a higher pharmaceutical input (about 3.4 times greater) into the river than the wastewater treatment plant downstream! But only if it rains.
The recommendation for next year’s festival? Better toilet facilities! I would definitely recommend packing wellies if you’re thinking of going though.
Elinor Richards
How do your reindeer fly?
— What powers Santa’s sleigh?
So, on Saturday evening, Santa will fire up the reindeer and set off around the globe once again. In fact, you can track his flight. But how do those reindeer fly, it could all be to do with Christmas Spirit, but it’s long been suggested there’s a slightly more pharmacological explanation
On a mushroom hunt a few years ago I learnt how to identify some common, edible mushrooms, and to spot some poisonous ones as well. One of the most well known is fly agaric, or Amanita muscaria. The name comes from its use as a fly poison, but for bigger animals like reindeer its not so much poisonous as fun. In fact, I was told that upon smelling a crushed mushroom, reindeer will come from miles around to eat some. Why? Because of the psychoactive compounds the mushrooms contain.
The psychoactive compounds in fly agaric include, muscarine, which mimics the neurotransmitter acetylcholine, and the two related compounds ibotenic acid (below) and muscimol (bottom), that mimic glutamic acid and GABA respectively.
Now, the story goes that it’s not just reindeer that like to get high from the mushrooms, but also the locals. Sometimes they eat it, and sometimes they use the reindeer as a filter, drinking the urine, which obviously contains a lower does of the psychoactive compounds, as well as their metabolites. So could this be where the story of flying reindeer comes from – tripping ruminants?
Whatever your opinion, it’s at least a salutary lesson in making sure you identify your mushrooms properly, so you avoid any unwelcome side effects. Or at least, talk to Frank.
Laura Howes
Packs To Perfection Episode 8 Almost 100% chemistry (Fifa 12) – Video
Hey what's up guys its UniqueRiggers and in this video I open a few packs and talk about the players I get in packs and also show you my team so far.
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Packs To Perfection Episode 8 Almost 100% chemistry (Fifa 12) - Video
I’m dreaming of a white Christmas…
Somehow Christmas time always feels more magical when there’s snow about. As snowflakes drift down and stack against frozen panes, you sink deeper into the sofa to sleep off the lunchtime overindulgence. And as you sit there the world goes silent as a white blanket settles leaving the landscape an undulating mass of indistinct shapes. But while 
we’re all familiar with these beautiful six-pointed stars of ice, have you ever stopped to think about how they form? What are the chemical and physical processes that make a snowflake grow into the shape it is?
As it is, each and every tiny snowflake has a humble beginning – a microscopic seed. This can be a speck of dust or some other particle – organic or inorganic. So, as the air temperature falls, water vapour coalesces around this seed and the snowflake begins to grow. As the water molecules freeze around the seed they form a crystal with six-fold symmetry. This symmetry is an intrinsic property of ice crystals and is due to the way the water molecules stack when they freeze. As the ice crystal grows it retains this hexagonal structure and builds upon it. This gives it its flat, plate-like structure with the six pointed shape we know so well.
Oxygen atoms are in red while hydrogens are marked out by grey bars © Ken Libbrecht
The hexagonal crystal lattice gives the snowflake its underlying structure and from there it grows by a process known as faceting. As the ice crystal grows the ‘rough’ edges with the most ‘dangling’ bonds grow fastest until only the smoother facets – geometric faces of the crystals – remain. These then grow in a uniform manner and, on their own, would result in ice crystals that were hexagonal columns. The complex branching patterns that give snowflakes their unique and beautiful shapes is down to small imperfections appearing in the facets, which are then quickly amplified by the stacking of more and more molecules of water at these points.
One man who has certainly spent a lot of time considering the shape and structure of snowflakes is Ken Libbrecht, at Caltech in the US. Libbrecht, orginally an atomic- and astro-physicist, says he became fascinated by snowflakes when he first saw a morphology diagram of how different snowflake structures form at different temperatures. If, like me, you’ve been watching the BBC’s brilliant Frozen Planet series then you’ll already be familiar with some of his work: high defintion videos of snowflakes growing.
Libbrecht says he got a call from the Frozen Planet team who told him that they wanted to use his videos of growing snowflakes on the programme. However, to date, Libbrecht hadn’t created any high quality videos. ‘Right before the BBC called it popped into my head that this is how to do [high definition videos], and when they called I said, “Great, I need a little money to do it”.’ Libbrecht went on to make a number of changes to his apparatus and produced the amazing videos that the Frozen Planet team were then able to model and superimpose on to the footage above.
© Ken Libbrecht
As a result of this collaboration with the BBC, Libbrecht says this set him off on exploring another phenomenon. As snowflakes grow – unlike other crystals – their edges actually get sharper. He thinks that this may be linked to surface melting, which occurs when an ice crystal warms to nearer to 0°C and the molecules near the surface become less tightly bound and the structure becomes more amorphous. At the sharp edge of the ice crystal there are fewer neighbouring molecules to stabilise the lattice in this region and surface melting increases, this leads to further growth of the crystal making them even sharper and so on. It’s a process of positive feedback that gives ice crystals their razor sharp edge, although why they grow faster as they get sharper is still something of a puzzle.
A growing ice crystal © Ken Libbrecht
However, Libbrecht says that building up a picture of this process will be extremely difficult. Ice crystals have a high vapour pressure so water molecules are coming and going at a prodigious rate. As the structure is in a constant state of flux it makes it very difficult to get an idea of what’s going on. He compares it with trying to take a clear picture in the midst of a hurricane. If you want to find out more about the fascinating world ice crystals and some experiments you can do then check out the Snow Crystals website.
And if all this talk of snow and ice has left you feeling distinctly chilly, then sit back and warm up by a real (virtual) log fire. Is there anything people won’t film and put on YouTube?
Patrick Walter
Chemistry in its element – tartrazine
What comes to mind when you hear the term E numbers? Hyperactive children? Or a simple labelling system for food additives? In this week’s Chemistry in its element podcast, Brian Clegg admits that while the health worries over tartrazine – perhaps the most famous E number of all – might be justified, it brightens up our lives in other ways.
Kara
Video compilation of Kara Tointon
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Kara
Alienn vs Stereopanic – Chemical Kinetic (HD) – Video
Alienn vs Stereopanic - Chemical Kinetic ~ One EP (2011)
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Alienn vs Stereopanic - Chemical Kinetic (HD) - Video
Chemistry – How to Find a Photon Wavelength – Video
yourCHEMcoach.com Mr. Causey explains how to find the wavelength of a photon using the energy and Planck's equation.
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Chemistry - How to Find a Photon Wavelength - Video
Amnesia The Dark Descent Walkthrough – Part 4 Chemistry Let’s Play – Video
Amnesia the Dark Descent Walkthrough - Part 1 My Name is Daniel Let's Play http://www.youtube.com Amnesia the Dark Descent Walkthrough! Walkthrough and Let's Play Playthrough of Amnesia the Dark Descent Walkthrough with Live Gameplay and Commentary. Series Playlist: bit.ly
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Amnesia The Dark Descent Walkthrough - Part 4 Chemistry Let's Play - Video