illuminating science

When I was younger (and still to a lesser extent now) I used to be a magician - I’d do shows at kids parties, retirement homes, that kind of thing. It was pretty good fun, though stressful at times, and it was always very cool to be able to do all these different effects (my family, particularly my grandfather loved it!) I’ve actually just started getting back into it, particularly with card work - I really enjoy card magic and working with cards. Very satisfying, and not so gimicky as all the stage magic, though I like that too.

But it’s funny how much cross-over there can be - I was just reading about Newton’s Nightmare, a magic “trick” that basically just uses Lenz’s law, which says that when a magnet falls down a tube, it generates currents in the tube which in turn generate magnetic fields which act back on the magnet - all of which says, a magnet falls slowly down a metal tube. Knowing this basic physics, can you work out what the magician is up to?

Another neat one is the Rice Jar, where the magician is able to lift up an entire jar of rice using a chopstick. As I read it, I thought I’d seen something like that before…a little googling came up with
Planet Science, and a fascinating discussion about how rice grains when shaken down will become dense enough that pushing a knife (or other object…) in will compress the grains so that they compress right back on a knife that is thrust into them - effectively holding it in place! Although I would never normally reveal a trick, here I’m simply giving you a reference to some interesting science. If you can work it out from there, good on you! Who said science isn’t useful?!

Finally, some great little on-line, self working card tricks. The first one is the first card trick I ever learned, I think, although when I knew it it was called “Sim Sala Bim” (Notice there are 10 letters in that magic word…That’s relevant for any intrepid magician who wants to uncover the workings of this trick!) Try it a few times, and see if you can work out what’s going on - you can do it with real cards too! The second trick on that page is very clever - stumped me the first couple of times!

Of course, at the end of the day, although science can probably solve some magic tricks for you, in many ways it probably makes it harder to understand what’s happening. Magic relies a lot on you expecting things to work a certain way - shuffling cards, coins clinking, etc. It’s sometimes harder to do magic for little kids because they don’t have this firm knowledge of what should happen, and are sometimes more likely to see what really does happen instead. But if when watching a magician your only thought is to work out how he/she did it, then the magician has indeed failed at their task - which is to entertain.

Guest poster Brett sent me this a little while ago, regarding free will - not just about whether we have free will, but whether that means that particles do too! There’s a little bit of higher level physics here, but you should be able to get the gist of it regardless. Food for thought indeed!

Often when science and philosophy collide, we get out something that is truly remarkable for both sides. Like when we showed that regular
objects like tables, chairs and people were actually composed of tiny particles, it raised questions of “Well, what does it mean to be me? I
feel like I’m different from tables and chairs, but on the atomic level, I’m not!” And let’s not even start with astrophysics and genetics colliding with certain religious beliefs.

Recently, Princeton mathematicians John Conway and Simon Kochen proposed a startling new theorem: “The Free Will theorem”. In general, provocative terms, it says that if you take as axioms stuff that most scientists believe, then if scientists have free will, then so do the particles that they measure. This is an interesting new form of a “No Hidden variables” theorem.

Specifically we suppose that:

• If two particles have total angular momentum 0, and one has angular momentum s, then the other must have angular momentum -s,
• If you measure the squared spin of a spin-1 particle in three mutually orthogonal directions, you will get two ones and one zero, in some
  order.
• There is a finite upper limit to the speed at which you can transmit information.

The first two assumptions (called TWIN and SPIN) have been experimentally verified, and the last one (called FIN) is readily
believable (Einstein’s relativity says that this limit is the speed of light, but this axiom needs only some limit, not specifically
that one).

Then what Conway and Kochen have shown is that if you (as a scientist) have some ability to freely choose which directions you want to
measure the spin of a particle, the particle has exactly the same kind of choice of the value of spin in those directions! This is rather
remarkable. Interestingly, if you don’t like this result, then you must have a problem with one of the three assumptions given
above. Since two of these results are experimentally verified, and the third seems rather reasonable (especially if you like relativity), you
need to do a lot of work to get around this “free will” problem if you don’t like it.

The details are a little technical, but you can check them out here.
The Daily Princetonian has a good article on it as well.

Well, today I’m setting out for the Torres Strait Islands. Jenny Riesz and I are going on part II of our World Year of Physics trip to regional Queensland (Australia), and visiting this group of islands at the north of Australia. Most of the people there are indigenous to the islands, originating from Papau New Guinea, and are distinct from Australian Aboriginies. The islands are all quite small, with just one school each for most, so it’s going to quite an experience for us!

We’re going to be travelling around (by 4 seater planes!) between the various islands and doing physics shows and workshops at the schools. In most places, we’ll do a show for the whole school, then some hands-on workshops for the older grades. It’s quite similar to what we did in Mt Isa a few months back, but we’ve had to refine our show a little to be more compact - these planes don’t hold very much! I think, though, that our show is better for it, so that’s good. Best of all, we got to buy $1000+ worth of equipment from the states, so our house has been chaotic last week with carpet skates and water vortices and all sorts of cool equipment floating around. Great fun - definitely one of the perks about doing this stuff!

Again, though, it means my posting will possibly be a little infrequent for the next week. I’ve written a few things which I’ll post throughout the week, but I’m not sure if I’ll be keeping up with the latest news! So have a good weekend, and talk to you all later! (PS - The TSI have a reputation for fantastic seafood - my grandfather was stationed there during the war, and says he ate more crab than he can remember. Dugong and turtle too, which I won’t eat, but I’m definitely looking forward to the food! Yum!)

Yesterday was the School of Physical Sciences Poster Day at University of Queensland where I’m doing my PhD. Basically, it’s a day when all of the PhD students prepare posters on their work to be displayed, and they have a BBQ and everyone walks around and talks to people about their work. Part of it is that it’s a great way for everyone to learn a little more about the research activities other groups are doing (PhD students tend to be involved in pretty much everything!) but it’s also designed to give PhD students experience in presenting their work to other researchers, in preparation for doing just that at a real conference somewhere. To encourage people to participate, they award prizes for the best poster from each discipline (physics, maths and earth science) which includes a $500 travel grant to attend a conference. And hence this post, since I won the poster prize for physics It was for my poster “Quantum Mechanics in Biology”, which talks about my work in understanding the role of quantum mechanics in places like photosynthesis and vision. Just so we’re clear, I don’t believe that quantum mechanics is responsible for consciousness, and that quantum effects in the brain enable us to think - I find that too hard to swallow, although I’m open to being convinced. I’m really interested in more practical examples, like where biology has evolved to take advantage of all these weird quantum effects, like tunneling and particles being in two places at once, and used it to build high efficiency devices, like our eye. It’s a fascinating topic, and hopefully we’re contributing something useful by studying these systems from a physicists’ perspective. If you’re interested, here’s the abstract for my talk:

Quantum mechanics forms the basis of physics - but what role does it play in life? Of course, it determines the structure of proteins and the chemistry of bonds, but much more interesting is where biology has evolved to use uniquely quantum effects to do things better. Photosynthesis
and vision are just two examples - Roger Penrose and others have even suggested that quantum coherence is the basic of consciousness! However, for any of this to be possible, evolution would have to overcome the problem of strong decoherence from the “hot and wet” environment.

We’ve shown that the interaction of biomolecules with the surrounding proteins and solvent can be described by the spin-boson model, which is very useful for studying decoherence and exhibits rich (non-trivial!) many body physics. We’ve then used these models to study systems of biomolecules coupled by FRET (Fluorescence Resonant Energy Transfer), in particular the light harvesting complexes of photosynthesis. And it may be that FRET spectroscopy might be useful to experimentally investigate the cross-over from classical to quantum behaviour.

Now I’ve just got to decide where I want to go!

An interesting report out about global warming - rather than focusing on the economic or environmental issues, it’s warning Australians about the heat related deaths which a rise in temperature could produce.

I hdan’t ever really thought about it myself - I’d always imagined global warming to be a small effect on a local scale which gets amplified due to the huge area being affected. (Like, temperature goes up 0.5 degrees, and we get massive storms.)

They’re talking about things like tropical disease spreading, and just plain old heatstroke. One thing they don’t mention is exactly what temperature change is required for all this to take effect. Are we talking a 2-3 degree increase all the time, or is it more that the extremes of weather change (e.g., really hot summers)? Or perhaps a combination of the two?

Release by the Australian Medical Association and the Australian Conservation Foundation, it seems that they’re trying to press home the idea that global warming is really going to affect you, the individual, and you should be worried about it. It could kill you. I guess that in some ways, whatever works is great. But in other ways, it’s disappointing if the only way that people will sit up and take notice is if they think their own lives are at stake.

Actually, I’d be interested to see a current study on people’s attitudes towards global warming, and then break it down to academics, business people, etc. Anyone know of a report like that?

I’d love to hear from someone who knows more about this than me: a mathematician from New South Wales (Australia!) claims to have developed a new trigonometry, i.e., a new way of dealing with angles and triangles.

Apparetly, in Norman Wildberger’s formulation, you don’t worry about angles and distances, and instead work in “spread” (which is between 0 for parallel lines and 1 for right angles) and “quadrance” which is just distance squared. He claims that this produces equations which can be solved “exactly” rather than the approximations that go with sine and cos that you might be familiar with from school.

To me, this sounds awfully fishy. (I’m a skeptical sort of guy, aren’t I?) The whole 0 to 1 thing sounds a bit like mapping the angle to the sine of the angle (spread = sin(theta), say) and I wonder if using distance squared (his “quadrance”) isn’t just a convenient way of using Pythagoras’s theorem (base^2 + side^2 = hypotenuse^2 - what you use to find the long edge of a right angled triangle! In his quadrances, it sounds like the sum of the base and the side of the triangle give you the hypotenuse straight out (rather than having to square and square root things.

Furthermore, even if his equations could somehow give “exact” answers (which I doubt - I’m sure there’s a theorem or something here!) having 10 decimals places is more than enough for any real purpose (e.g., engineering) while mathematicians would just leave sin(theta) as…sin(theta)! (And no, that’s not a factorial sign for the geeky mathematicans out there…)

I’m not going to buy his book based on this story, although I’m puzzled that he got it published if this is all there is to it. Perhaps it really just simplifies enough stuff that he thinks it’s a justifiable suggestion? I really can’t see us changing the way we deal with angles etc now, and, ultimately, it’s just a different way of looking at the same thing - there’s nothing wrong with maths now, and I suspect (I’m almost certain, in fact!) there’s nothing we can’t do now that we could do with his formulation. So anyone with any thoughts would be most welcome to comment!

Slightly spooky story on Nature News today, about the disappearance of three lab mice infected with the plague (or rather, a bacteria that causes the (bubonic) plague). It’s slightly odd - there were three groups of mice with different vaccinations, and one mouse was lost from each group. I’m not sure whether the mice were all together or not - if they were in separate cages, that seems like a pretty unlikely coincidence. If they were all together, then if you were losing mice at random, then you’ve got a 20% chance of losing one of each if my back of the envelope calculation is right, which isn’t so unbelievable (see? Maths is useful everywhere!)

It seems that the media haven’t got a hold of this one, or have decided that it’s not worth trying to scare everyone to death over the possibility of a plague outbreak (in reality, it’s not an issue - in the old days the plague was actually spread by fleas that came with the mice/rats, rather than the rats itself, so we’re not really in danger of an outbreak. And apparently a couple of thousand people catch the plague each year anyway, and it can be treated by antibiotics.) But even so, if three mice can just vanish, you’ve got to wonder about security procedures.

Or maybe the mice are smarter than they look…

So, supposedly, a man yesterday built up 30,000 volts of static electricity in the jacket that he was wearing while walking around town. Apparently, he left a trail of scorch marks and molten plastic behind him, as he discharged electricity into his surroundings.

Hmm.

This sounds vaguely fishy to me, but part of that I suspect will be dodgy reporting. Let’s take the article as gospel first, then see if can’t tweak it a little to make more sense.

First of all, the dielectric breakdown of air is 30,000 volts per centimetre. That means, that to get a one centimetre spark you need something charge to 30,000 volts. Alternatively, if you charge something to over 30,000 volts and put a grounding rod (which probably includes another person) within 1cm of it, you’ll get a spark as the object discharges its charge into the grounding rod.

So, could our friend get charged to 30,000 volts? In reality, it’s probably not that hard - I can make a capacitor out of a film canister and alfoil that charges to 3,000 volts just by rubbing some plastic tubing with cloth. And my Van de Graff generator can build up 300,000 volts with no effort. So, it’s conceivable that if he had a coat capable of storing charge well, he might build up a 1cm spark. (You’ve probably seen small sparks if you take of a jacked in a cold night in a dark room, or if you stroke your cat vigorously - each spark is probably of order 3,000 volts discharging.) I’m not clear though, how the coat gets charged - I guess just by him walking, or sliding in and out of his car, but it’s a little hard to swallow.

Let’s assume though that it’s possible. Could this spark melt plastic, and burn carpet? The thing is, most of these sparks only contain a relatively small number of electrons. That’s why a 3,000 volt shock from rubbing your feet on the carpet doesn’t kill you, but a 240 volt power supply (or even a 12V car battery) will - the latter two can pump out a huge number of electrons. It’s really the current that’s the killer. I’ve been shocked off the Van de Graff, and it tingles a little bit but nothing deadly. Furthermore, the most this 30,000 volts can only go 1cm - if it’s really in his jacket, it’s not going to reach very far, and if it’s in his shoes, it should just discharge into the earth and be done with it. So, I can’t see that 30,000 volts is responsible for all this.

So, the most likely option is that he was charged much higher - say, 3 million volts. That would get you a metre of spark, capable of reaching the floor. But again, this spark really can’t contain many electrons - could it really melt plastic? I’m trying to think of a back of the envelope calculation here, but I’m not quite sure. (The energy would be charge*voltage, I guess - how much energy is needed to melt plastic, and so how much charge is needed?)

Either way, this seems a slightly improbably scenario. If nothing else, once he’s discharged, it would take some time for him to recharge! He’s not going to be “giving off voltage” constantly (and note, that one typically gives off current!) Interestingly, famed science communicator Dr. Karl was contacted about this - I have to say, that’s pretty cool He seemed to think it plausible, but I remain a little skeptical. Unfortuantely, we’ll probably never hear from him again in the media (and the Powers that Be have probably already whisked away his jacket for their evil projects…) so we’ll probably have to remain in ignorance. Too bad!

I’ve just been reading a fascinating story from Mike Brown, who recently discovered a new planet. I’d been overseas at the time, and had only heard vaguely about it, so it was very cool to read a first hand description! You can see the pictures of the sky, and try and spot the planet yourself. He talks about how planets and asteroids are named, and what his thoughts are for naming this one (although he falls short of actually saying what name he’s submitted for consideration!)

Most interestingly, he talks about what makes a planet a planet, and whether Pluto should indeed have that exulted status. In reality, Pluto isn’t much more than a big rock - there’s nothing to distinguish it from the many other rocks in that region, except for its size. So many purists have been arguing that Pluto should be demoted from planet status, but of course (as Mike Brown insightfully points out) the idea that there are 9 planets is firmly ingrained in our society (not to mention countless posters on school walls!) The powers that be are currently debating whether or not this new object should really be given the title planet. I really hope they do decide to - sure, it’ll make things a little more compicated for a while, but if I were a school student I’d find it very exciting to add another planet to our solar system! And if nothing else, it gives some sort of scientific consistency to the whole thing (”A planet is any object with a size greater than Pluto”). Not perfect, but it’ll do.

A slightly humorous, but also slightly alarming story I read today about criminals using TV shows like CSI to outwit forensic experts. Apparently, more and more criminals are wearing gloves, and are trying tricks like leaving old cigarette butts at the scene of the crime that they picked up from the street. Honestly though, that’s pretty simple stuff - don’t leave fingerprints, maybe wear a hairnet (actually, I always thought a scuba diving suit would be the way to go, albeit somewhat conspicuous) and maybe leave some sort of a false trail. The scientists who conducted the research did say, though, that at best the criminals can hope to through the police down the wrong track initially.

Interestingly, I actually found out about this after doing a show at the Police Museum in Brisbane, where they put on a little bit of a display about forensics. I was really interested in finding out more, and perhaps even doing a tour of their labs, but they said that they couldn’t - firstly, because they have all their ongoing investigation stuff in the room, which would all have to be secured and cleared away first, but also because they don’t want anyone finding out too much about how they identify criminals and the techniques and equipment they use. Rats!

I’ve got to wonder though - is there any more information on a show like CSI than there is in a really good detective novel? What about Patricia Cornwell and her series about Kay Scarpetta, forensic pathologist? It’s probably a little on the light weight side of things, and I’ll bet there are books out there written by even greater experts on modern forensic techniques. I suspect in reality that criminals who are smart enough to do things right will find the information no matter what (heck, I’m sure there’s a website with all the details in easy Googling range!) and what this study has really seen is the, er, less intelligent criminals picking up a few tidbits on their stolen TV.

And if you’re interested in larger scale, world dominations projects, you’re probably more interested in these tips for evil overlords.