Post Tagged with: "chemistry"

Garlic Challenge, the results show!

Back in October I posed a question: Is there any truth in the old wives tale that rubbing your hands on stainless steel gets rid of garlic smells? Various theories as to how steel may achieve this were posited. But I wanted to know if there was a real effect in the first place. Kitchen chemists everywhere helped answer this by taking part in a stinky citizen science challenge. And the results are, well, interesting.

Garlic

I asked people to conduct a quick experiment whilst prepping dinner. The task was simply to rub the palms of their hands with garlic. Then treat one hand with a wipe from a stainless steel spoon and the other with a wooden spoon. Finally participants asked some other poor soul to take a sniff of their hands and report on whether there was a discernible difference.

Thanks to everyone who took up the garlic challenge (especially the person who did their experimenting whilst cooking Christmas dinner).

And so to the results.

These were collected via surveymonkey, with the question “Which hand smelt more of garlic?” and the answer choices a) The hand rubbed with the wooden spoon, b) The hand rubbed with the stainless steel spoon, c) Couldn’t tell the difference.

44 allium lovers responded. Of those 17 thought the hand treated with the wooden spoon smelt more garlicky, 6 said the stainless steel treated hand was the stinkier. So far, so good. Looks like the stainless steel effect might be real. But here’s the rub, there’s still the other 21 responses, none of whom could tell the difference between the smelly hands.

 

Screen Shot 2013-12-31 at 10.48.37

 

So we’ve got results that are significantly different from an even distribution between the options (the two-tailed P value equals 0.0163 ,according to a chi squared test) . However, the stainless steel treatment seems to be only about 38% effective, assuming the wooden spoon is a good negative control. But maybe the abrasive, absorbent wooden spoon is also quite good at removing garlic smells? In which case the effectiveness of the stainless steel is an underestimate.

Oh well, sorry people, but it looks like I can’t really offer a definitive answer. In hind sight I think the experimental design could have been better. A before and after spoon treatment sniff test would have been a good idea. And maybe a better negative control was in order.

Looks like another round of experiments  could be in order. Or can anyone offer a better way of analysing the data (I suspect sensitivity vs specificity analysis might be more appropriate)?

By December 31, 2013 5 comments fun

Twitter Brain’s Chemistry Novel (and other book) recommendations

I’ve been looking for an easy to read book (fiction or non-fiction) to send out to chemistry students before they arrive at Uni. The plan is to have all our first years read the same book before they arrive. With any luck it will give them something to chat about and give our first few lectures a point of reference.

So I asked the twitter brain for its chemistry book recommendations, and here’s what it came up with.

  1. @Sci_ents @DrRubidium Anyone say Greg Benford’s Timescape? More physics but includes NMR, time travel, eco-disaster, and academics.
  2. @Sci_ents @DrRubidium I can recommend an author… Peter Watts.. his first series is chock full of science goodness including chemistry
  3. @sci_ents we’re partial to this one: ht.ly/mrHGn Short stories about a deadly assassin who uses a different poison for each kill
  4. @ChemistryWorld @Sci_ents My friend told me to read “The Disappearing Spoon” by Sam Kean. I just checked it out from the library!
  5. @Sci_ents I enjoyed ‘The Girls of Atomic City.” It tells the story of the nuclear bomb development from the “blue collar” people working…
  6. @simonbayly @Sci_ents @ChemistryWorld It was Mr Levi whom inspired me onto the chemical trail at age 14. Highly recommended reading.
  7. @BytesizeScience @Sci_ents Goethe’s “Elective Affinities” is a Classical example, but highly metaphorical. Downhill from there.
  8. @Sci_ents @ChemistryWorld Mr Tompkins by George Gamow
  9. @Sci_ents @ChemistryWorld The Periodic Table by Primo Levi isn’t a novel exactly, but it is one of the best books ever.
  10. @Sci_ents @ChemistryWorld @Sci_ents not sure if this counts but “cat’s cradle” by Vonnegut has some nice ideas en.wikipedia.org/wiki/Ice-nine
  11. @Sci_ents Interesting physics and chemistry in Reflex by Dick Francis. Not exactly concepts though, more application.
  12. @Sci_ents @ChemistryWorld not really a novel but The Periodic Kingdom by P W Atkins is a great read
  13. @Sci_ents The Documents in the Case, Dorothy L. Sayers. Not much chemistry until the clincher which is chemical concept. (DM for spoiler)
  14. @Sci_ents When I was undergrad, one grad inorg cume at WUSTL included question, “Who killed Missy Moonbeam in The Delta Star?”
  15. @Sci_ents @ChemistryWorld
    Uncle Tungsten: Memories of a Chemical Boyhood by Oliver Sacks
  16. @Sci_ents @ChemistryWorld Susan Gaines’ Carbon Dreams?
  17. @Sci_ents @ChemistryWorld – Napoleon’s Buttons: How 17 Molecules Changed History, Penny Le Couteur
  18. @Sci_ents Not exactly fitting the criteria but Primo Levi’s Periodic Table comes to mind
  19. @Sci_ents Primo Levi’s The Periodic Table en.wikipedia.org/wiki/Primo_Levi some named as best science novel ever
  20. @Sci_ents @ChemistryWorld or cat’s cradle if gravity’s rainbow is too much of a slogger
  21. @Sci_ents Emm short answer no. Long shot- Dune. Spice as a drug, water harvesting and terraforming. Best I can do ad hoc
  22. @Sci_ents A Whiff of Death (I. Asimov) — murder mystery set in Chemistry department… The Delta Star (J. Wambaugh) — similar plot.
  23. @Sci_ents @ChemistryWorld gravity’s rainbow, imopolex g

 

Did we miss any?

Say it with Molecules

Capsaicin necklace anyone?

Anyone fancy some quality, tasteful geeky  jewellery? I don’t think you could do much better than this. Its accurate, sterling silver and subtly nerdy, which means I might just about be able to get away with buying some for the other half. 

There’s a whole range of your favourite molecules in wearable form, from capsaicin necklaces to nucleotide earrings and serotonin cuff links.

All available from madewithmolecules.com.

Hat tip to @DrBWahab for the link.

By March 25, 2013 2 comments fun

Homeopathy: Science or Sympathetic Magic?

As a new contributor to Chemistry Blog, I’ve decided to ‘break myself in’ by tackling the somewhat controversial and thought-provoking topic of homeopathy.  As I write, we find ourselves part way through ‘World Homeopathy Awareness Week’, so the subject is enjoying quite a high profile and twitter seems to be alive with discussion on the matter.

 

Before I go further, I feel I should declare myself to be a sceptic.  I’m doubtful as to whether any other point of view on this subject would be published on Chemistry Blog –so that will come as no surprise.  After completing my chemistry studies, I chose a career in the pharmaceutical industry –to make a difference.  I also rely on daily medication to manage my own condition.  I’m therefore very aware of the difference proven chemistry can make to the quality of people’s lives.  The science of drug development is founded on proven facts; a great deal of money, effort, time and hard evidence is required for just one new drug to reach the market –I will return to this subject in a later article.

 

What are the principles of homeopathy?

 

Homeopathy is an alternative medicine, based on the principle of treating like with like.  Patients are treated with highly dilute preparations believed to cause symptoms in a healthy person, similar to those being experienced in the patient.  Commonly used dilutions are 10C and 30C.

 

To achieve a 30C dilution, the ‘active’ ingredient is diluted 1 part in 100 –and then a drop of this solution would be diluted to 1 part in 100 and so on for 30 repetitions.  The resulting final solution would be 1 part active in 1 followed by 60 zeroes.  To put this number in perspective; one molecule of ‘active’ in a volume the size of the entire observable universe would be 40C.  Homeopaths claim a process called ‘succussion’, the act of striking the vessel containing the solution against an elastic surface 10 times at each stage of the dilution process, activates the ‘vital energy’ of the diluted substance and they talk, not in terms of dilution, but in terms of ‘dynamisation’ or ‘potentisation’.

 

As chemists we know there is a limit to any dilution that can be made without losing the original substance entirely.  This limit is related to Avogadro’s number and in homeopathic terms roughly 1 part in 1024 –equivalent to a 12C preparation.  A 30C preparation would require giving 2 billion doses per second to 6 billion people for 4 billion years to deliver a single molecule of the original material to any patient.  It is worth pointing out here that homeopathy dates from a time predating the discovery of atoms and molecules, so it was a widely held belief that a substance could be diluted ‘ad infinitum’.

 

Homeopaths believe the more dilute a preparation is the more effective it is. They believe the diluent used (usually water) has a memory of the active molecule it once contained.  My professional life as an analytical chemist would be a living nightmare if this were the case and carefully prepared diluents were ‘remembering’ the properties of the all the compounds they had contained.  Just imagine what the HPLC chromatograms would look like!  There would simply be no point in trying to keep the equipment free from contamination.  The notion of ‘molecular memory’ is at best implausible; it suggests the shape of a molecule is more important than its chemistry. Putting reason aside for a moment and accepting that water has memory –how would it emulate the chemistry of that molecule?  That very notion would require our current understanding of chemistry to be re-written and that understanding has provided us with thousands of medications which have been proven to be effective.

 

Clearly, if homeopathy achieves a successful clinical outcome, there is something else at work here. There is likely to be a significant ‘placebo effect’ and there is anecdotal evidence to support this idea. Also, the act of consulting the homeopath and the attention and sympathy the practitioner gives the patient –is believed to support the healing process. This, however, can be dangerous when the practitioner advises the patient against engaging with conventional medicine –this can, and has, resulted in tragic consequences.

 

As a complementary therapy, homeopathy appears to benefit some and as such it has its place in modern medicine. It isn’t sensible to use it as the only course of treatment for any condition, especially not a serious disease. The ‘science’ doesn’t stack up -it’s just sympathetic magic.

By April 12, 2012 15 comments general chemistry, opinion