SciBlogs

Archive November 2009

The best of Royal Society publishing – 350 years’ worth! aimee whitcroft Nov 30

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So, this is seriously, seriously cool. 350 years’ worth of the Royal Society of London’s best published papers.

(click on the picture to visit the site)

To expand, (teehee), it’s actually an interactive, explorable timeline. And it’s been launched to commemorate the Society’s 350th birthday next year. The RS is definitely wearing the age quite well, all in all :)

The timeline’s also got a bunch of fantastic images for those of you interested in imagery/design and is, generally, an awesome website.

The first papers are a bit grim, involving bellows and dogs’ lungs. The last (most recent) paper was the RS’s fascinating paper on geoengineering, and many of the 60 papers available coincide with major historical events, although they aren’t necessarily connected. For example, in 2008, the term ‘Cubism’ was adopted; the same year, a paper was published entitled ‘Reflection of alpha particles from thin foil’.

And, of course, people with an interest in language, or at the very least the English bits thereof, will find the changing expression fascinating. Not only in and of itself, but for what it can tell us about attitudes and beliefs at the time (for a great example, have a look at Fabiana’s hilarious post on cockroaches).

And, without further ado, I shall leave you all here, as I want to go frolick in all this sciency goodness. I’m sure you do too.

Wherefore the hammerhead? aimee whitcroft Nov 29

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Fantastic stuff, this. Well, for those of us who, when little and naturally curious about everything*, wondered why, exactly, it was that hammerheads had hammerheads. As it were.
Scalloped hammerhead shark, Sphyrna lewini, Hawaii, USA (Pacific ocean)
UW118-2, (c) Andrew Seale

There are many possible reasons for this. It could be that a (or the, depending on your preference) creator thought it looked kinda cool, and was going through a flat-headed creature phase. Or because it makes said sharks look, you know, really really menacing. Or, alternatively, really, really ridiculous.

And learned people, of course, being learned, have posited their own theory: that it gives hammerhead sharks great stereovision and depth perception. Or not. The thing, up until this paper released last week, no one had actually bothered to test this assumption.

It has been suggested that, in fact, since their eyes are on the sides of their heads (I’m talking about the sharks here), rather than facing forward, that they couldn’t have binocular vision. However, other clever people and television shows have claimed eyesight benefits. Who is right?

It turns out, the guys who posited better vision. The paper’s authors looked at a range of different shark species, bother hammerhead and pointy-nosed. Included were bonnetheads (narrow) and scalloped hammerheads (wide).

Bonnethead hammerhead (Sphyrna tiburo)

Scalloped hammerhead (Sphyrna lewini)
© Doug Perrine

So they got a whole lotta sharks and then tested their eyesight with a version of the whole ‘moving the torch in front of your eyes’ thing. They weren’t testing for concussion, but were instead measuring the electrical activities of the sharks’ eyes.

First, they looked at monocular vision, and found that hammerheads kick ass. As it were. The fields were wider than pointy-nosed blacknose and lemon sharks (for example), with the scalloped hammerhead having a 182 degree range, and the bonnethead a very respectable 176 deg.

They then took these measurements, and plotted them to see whether the monocular fields overlapped. Which they did. Apparently, the scalloped hammerhead had an overlap of some 32 degrees, and the bonnethead had 13 degrees. The most hammerheady of all, the winghead shark, had 48 degrees!

Then, they factored in some other stuff such as head and eye movements, and watched those overlaps grow.

In short, the television series (and clever people) were right. That weird head shape does indeed improve depth perception and binocular vision.

Mostly awesomely, it also gives some hammerheads a 360 degree rear view (or very close) – one of the few occasions where the television people have underrepresented the situation. Gosh.

* Note: I saw a paper recently (for the life of me can’t remember where) that said that the whole ‘why’ phase small kids go through isn’t actually an attempt to make mommy/daddy’s brain drip out their nose, but is, instead, because kids actually do want the answer to their questions. Go figure.
(Postnote: Calvin’s dad’s answer to this situation is quite tempting, though. And here’s some more inspiration.)

The LHC’s first collisions aimee whitcroft Nov 25

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Woohoo! I couldn’t, personally, be more thrilled.


No doubt, people who actually understand properly the physics and true awesomeness behind the LHC couldn’t be more thrilled either. Even more so than I.

Because, * fanfare *, the first collisions in the new, better-than-broken, up-and-running, ghost-in-the-machine lacking LHC have been observed!

A brief history lesson – the LHC, or Large Hadron Collider, is a truly gobsmacking feat of engineering which has taken a decade to build, billions of euros, and, no doubt, the sanity (or at least youth) of a number of engineers who’ve had to fight various problems, including errant baguette-bearing birds, to finally get it up and running. Properly.

And why has this wonderfully photogenic machine been built? Why, to find new particles! Amongst other things, of course. Of particular interest is the possibility that our scientists may be able to spot the elusive Higgs boson. (I have a fantastic image in my head of scientists in khaki, with binoculars, and a David Attenborough voice-over). The Higgs boson, or ‘god particle’, has thus far only been theorised, but it’s thought that it could be what gives everything in the universe mass.

Basically, it works like this (there’s a better explanation here):

The Higgs boson (or particle) carries the Higgs field, which imparts mass to objects as they move through the field, kinda like this…

People evenly distributed in a room, akin to the Higgs field (CERN)

Then Thatcher (yes, yes, I know!) enters the room, people gather, mass increases (CERN)

Of course, the LHC has also lead to howls and terrors from various quarters about its potentially causing the end of the world, or a huge black hole, or something. Amusingly, some physicists even suggested that it (well, the universe) could be sabotaging itself from the future.

But I digress. The news here is that the first collisions have been observed, and they look like this!

The green lines denote changed particles (following the collision), which are, apparently, generally pions (not peons, although those can also be unstable during changing circumstances).

[Pions] are unstable particles consisting of an up quark and an anti-down (or an anti-up and a down). Though they are unstable, they live long enough to nearly always leave tracks in the detector.

Then, the yellow bits denote the silicon strip detectors responsible for recording our particles

After that, it all gets quite technical. A far more knowledgeable account of it, and the source of the quote above, can be found here (which, by the way, is a great blog).

Mostly, I’m just happy she’s started up, and I’d like to raise a toast to her: we’re happy to have you back with us, dear gal, and we look forward to the show!

There’s also a lovely Nat Geog article on it. I love the subheading ‘happy physicists’ – it’s a warm and fluffy thought.

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Climate centre hacked aimee whitcroft Nov 22

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This subject has already been covered on the web, but I haven’t seen it discussed yet on Sciblogs, so thought I would bring it to the fore.


Being quite aware that I don’t do the climate change thing (as it were), for no reason other than that there are other people far more qualified than me to do so.

But still, this is quite something…

To fill everyone in: the University of East Anglia, which is apparently one of Britain’s leading climate change research centres, has been hacked. The emails, covering 1991-2009, first appeared online on Nov 19th, and have since gained widespread attention.

And yes, this was a crime – the centre was hacked, and personal emails stolen and disseminated publicly. Not allowed. Not even slightly. No matter how one might justify it.

Further, lines from the emails are being used by climate change skeptics (deniers?) as proof of collusion between scientists. You know, as part of this huge conspiracy, involving thousands of scientists all over the world, in which anthropogenic climate change is all a big fib. Yes. That one.

The fact that the emails have been split up and discreet sentences used (for example, taking the phrase’ trick’ to mean deliberate obfuscation, or even outright lying, instead of a just-as-common phrase, to mean ‘clever technique’) alone is, basically, the same thing as cherry-picking and quote mining…a ‘trick’ used fairly often by…certain groups. And while not technically a crime, it is certainly dishonest. Taken out of context, even the most innocuous sentence can sound dastardly.

Not much more to say (there’s been plenty already written), and a little more serious than most of my posts, but it’s something I think important…

More info:

The teapot effect, end of aimee whitcroft Nov 12

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So apparently, there’s something called the teapot effect. Or, rather, there was.


No, it’s not what you might first imagine it is. At least, it’s not what I first imaged it was. Instead, it’s apparently the name used for the phenomenon whereby the spouts of teapots dribble, and even English women who’ve been pouring tea for posh friends for decades are unable to pour that perfect, immaculate cup of tea.

“Previous studies have shown that dribbling is the result of flow separation where the layer of fluid closest to the boundary becomes detached from it. When that happens, the fluid flows smoothly over the lip. But as the flow rate decreases, the boundary layer re-attaches to the surface causing dribbling.”

And here’s where fluid dynamicists have stepped up, donned their superhero cloaks, and sorted the problem. Huzzah!

The factors involved?

“Previous studies have shown that a number of factors effect this process such as the radius of curvature of the teapot lip, the speed of the flow and the “wettability” of the teapot material. But a full understanding of what’s going on has so far eluded scientists.

“Now Cyril Duez at the University of Lyon in France and a few amis, have identified the single factor at the heart of the problem and shown how to tackle it. They say that the culprit is a “hydro-capillary” effect that keeps the liquid in contact with the material as it leaves the lip. The previously identified factors all determine the strength of this hydro-cappillary effect.”

The solution is two-fold: make the lip of the teapot as thin as possible, and and coat it with superhydrophobic materials (materials, in other words, that really, really, really, really don’t like water).

Even more fun, apparently there are materials in which the superhydrophobicity can be turned on and off electronically. Meaning that to dribble or not to dribble would no longer be hypothetical…

And, because there’s no better way to end things than with wry, physics-based sarcasm, there was this comment, as well:

“(Of course, there are one or two other potential applications in shaping the fluid flow in microfluidic machines but these pale into insignificance compared with the teapot revolution in hand.)”

On another teapot-related note, I had not idea, but apparently teapot-blowing (again, not what you think) is something of an artform!

p.s. Yes, I know the original arXiv post isn’t that new – sadly, life has perforce distracted me somewhat of recent.

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