illuminating science

You never really appreciate your eyeballs or beating heart until you come into close contact with something that threatens one of them. In the last week, I’ve had an almost comical run of close enounters of the grievous-bodily-harm kind. Sure, there’s been the usual run of near death traffic experiences (not my fault - this time anyway!). And we’ll discount the potential artery clogging that might come with the start of my Christmas cooking spree.

In reverse order: Two days ago, there was an almighty “BANG!” in my office. I’m talking the window rattering, jump out of your seat, ear ringing kind. Okay, I’m not certain the windows rattled, but it scared the devil out of me, consciensciously and studiously working as I was. There’s the smell of burning electrical equipment, and a disturbing gurgling, fizzing and bubbling noise coming from within one of the power boxes in my room. Turns out a ballast exploded - a device which limits the current to a fluorescent light, and can also sometimes provide an initial voltage spike to get the fluorescent tube started. It also blew a fuse - but eventually it was all repaired. I’d never heard of a ballast (d’oh!) so this particular incident only really hurt my pride, and any years the initial fright took off me. Oh, and maybe hitting my head on the ceiling when I jumped! (Incidentally, did you know that a plasma, like what you find in a fluoro tube, has less and less resistance the more current that flows? If it weren’t for the ballast, providing a base resistance, the current in the fluoro would keep increasing until something blows!)

My second experience was again light bulb related - being the helpful, generous and caring grandson that I am, I went round to my grandparents place to help change a high and stuck lightbulb. Light switch is off? Yep. I took out the troublesome bulb, which much twisting and wiggling (and of the bulb, too) Go to put the next one in - and it suddenly lights up. Hmmm. Turns out, there was a second switch at the other end of the hall which also controls the light, and that configuration meant the light was on. I presume there really is minimal danger, so again no harm done, except for slightly elevated blood pressure. (What would a simple circuit allowing two switches to control one light bulb look like? It’s a fun one to think about - here’s one solution)

And I’m actually going to save my third experience for tomorrow - it’ll make a good post in and of itself

From the apparent moron Peter Coates who runs Xstrata Coal, a major player in the coal industry in Australia, courtesy of ABC News:

“Renewables are important. But they will always operate around the fringes or with the current technology they’ll operate around the fringes of baseload power, whether that be coal or nuclear, and climate change is a global problem that requires a global solution.

I stress whatever we do just in Australia will have absolutely no impact on world climate.

The article paraphrases this as “Mr Coates says coal is the only long-term viable solution to the world’s energy needs and any attempt to tackle climate change must include large developing nations.”

“Long-term” and “coal” don’t generally go together in the same sentence. Coal is a limited resource. Depending on who you talk to, we might exhaust it in 25 years, 75 years or 175 years, but it’s going to run out, sooner rather than later. At the very least, it’s going to become increasingly expensive to mine the reserves that still exist. I agree that nuclear power might be important, as it doesn’t depend on the time of day or weather conditions. But to make this sort of statement is just utter rubbish.

And yes, climate change does require a global solution - but that’s no excuse to just ignore our own obligations. Australia has one of the highest green house gas emissions “per person” in the world. Our population is small, compared to America or China, but to say that we have or will have no impact on world climate seems awfully bold - and I’d like to see this backed up with some facts.

Long and short of it: I don’t think we can really trust the head of a major coal company for a balanced, unbiased viewpoint!

My PhD examiners’ reports were tentatively due back on the 28th of November, less than a week away. However, I just found out that one examiner has a heavy workload, and so won’t be able to send their report until 20th of December! Drat! Of course, it’s not exactly unexpected - everyone’s busy, particularly at this time of year. Hopefully, though, I’ll get both reports by then, and I can work on them in early January, make all the changes, and get my thesis to the printery when it opens again on January 15th!

As I’ve mentioned previously, I’m also a magician and many years ago I used to perform at children’s parties, retirement homes, variety shows, etc. (Incidentally, I think those magic shows were a big part in developing my public speaking abilities and confidence - when you’re surrepticiously hiding a grapefruit in your hand you’ve got to learn to appear perfectly natural I highly recommend it!)

I mentioned in that post a few magic tricks which are based more on physics than magic, and I think I’ve found another one, this time based on a bit of maths and game theory.

The effect (I won’t reveal its true name) was basically that the magician plays a game of Tic-Tac-Toe with a volunteer from the audience. Then, after the game, you reveal a prediction of the game board - and it matches! I started to wonder how this might come about, as one thing I used to be interested in was tac-tac-toe strategy and winning positions (as sort of an introduction to more complex games’ stragies, like Connect 4) In particular, for Tic-Tac-Toe you don’t actually need to remember all that many “strategies”: either you’re forced to make a certain move to prevent your oponent from winning, or by rotating or flipping the board you can get back to one of a few basic positions which you know what to do with. I also thought of chess puzzles, where you must perform checkmate is 2 or 3 (or more) moves. Because of the complexity of chess, usually (but not always) the solution is to make a move to which your opponent has only has one response (or only one response that doesn’t lose immediately!) and continue that way - forcing them towards the checkmate position.

So I started to wonder: might it be possible, in fact, to force your volunteer to a certain tic-tac-toe board position? Intuitively, this seems a bit harder than just winning/drawing/losing, but it’s not overly so. We’ve got to make a few assumptions:

1. I can rotate either my prediction or the actual board so that they match
2. My oponent is going to play intelligently

The first condition is easily satisfied by making sure there’s no “up” direction (e.g., title at the top, footer at the bottom, etc) Then, I could either rotate the board casually while discussing it to the correct orientation, or I could just rotate my prediction when I produce it. The second assumption is a basic one of game theory, which helps us to find the best strategies for a variety of “games”, whether that’s tic-tac-toe, world economics or bargaining at the markets. The most important assumption is that if I’m about to win, they’ll try and stop me (i.e., if I’ve got two in a row, they’ll block it with one of theirs). I’m also going to play intelligently, but my “goal” is to force the board - not win!

I’m going to add one more assumption though:

3. The magician starts first

I did a little bit of playing, and here’s the board I came up with:

The Magician plays the Naughts (O’s) and went first, in the centre. The key thing is that there are only two possible plays for the volunteer - it looks like there are 8 squares left, but by rotating the board, there’s really only two choices - either a corner or a middle. Have a play of the board yourself - can you see how to force the oponent and reach this board from those two choices?

Here’s my solution:

Notice that regardless of which of the two place the volunteer plays, I force them into my winning position. If they played at a different corner or middle square, I just rotate the winning sequence in my mind and continue appropriately.

Now it’s certainly not the only winning sequence. Here’s another for a “middle” play:

Play through those two middle-play games. Both arrive at the same board, but considering the piece of magic we’re trying to perform, can you see why the first board is better?

In the pair of sequences I presented initially, both player’s moves are forced after the magician’s second response. The magician makes the first move to the centre - a logical move, since we all “know” it’s the “best” position. Then, the spectator gets a completely free choice (out of 8 squares!) and hopes they made the right one. The magician then makes a good move, that threatens a win - and from then on, both players are fighting just to stay alive. The game seems fair - both players seemed to be in with a chance to win, and it was just bad luck that it ended up a draw. Most importantly, there didn’t seem to be anything but good, honest, tic-tac-toe going on.

Contrast this with the second middle-play game - now, every move by the magician is free. All the volunteer does is respond and they’ve got no choice about where to play if they want to win. Quite aside from being boring, that’s what’s going to stick in their mind is that the magician forced every move they made, and the magician had a free choice every turn. When you produce the prediction board, that feeling of being manipulated is probably going to remain.

Finally, can we get around Assumption #3? If they go first and play in the centre, then by playing in the corner I’m usually able to force the board to look either like the board above or its mirror image. If I relax Assumption #1 to allow me to flip over the game or my prediction (e.g., by drawing one of them on an OHT) then in most cases I can get by. I’ve only found one case where if they don’t play perfectly I end up winning - it sort of violates Assumption #2, but it’s no immediately obvious it’s a losing move. If anyone can verify this and/or come up with a better method, I’d be interested in hearing from you!

Anyway, this was a very long post, but I hope it was interesting - I’ve got no way of knowing if my method is the same as the original magician’s (short of buying the trick!) but I think it’s quite workable. I’m going out to dinner tonight - who knows? I might try it out!

Tonight and for the next couple of days, the Leonid meteor shower will be at its peak. Now, before you get overly excited, it’s only fair to warn you there’s only expected to be about 10 meteors an hour (plus any other random meteors that normally appear - usually 5-10). That means you’ll have to wait on average 6 minutes between each meteor. The advantage is they’re all coming from the same region of sky, which means you can just lie back and watch. A further downside is they’re up from about 1am onwards - 3am probably being a good starting point.

The Leonids occur because we’re passing through the old debris stream of a comet (the Temple-Tuttle comet, in fact!) Small dust particles left behind hit our atmosphere and burn up, just like a space shuttle on re-entry. They get so hot they glow, appearing a bright streak, before burning up completely. About every 33 years, the Leonid shower becomes massively more intense - thousands of meteors an hour! Unfortunately, the last time this was supposed to happen, in ‘99, the shower was not quite that impressive - still many meteors, but at least for the Brisbane suburbs with our darn city lights, I wouldn’t have seen more than ~ 100. That’s still a lot (!) just not thousands

Anyway, if you’re awake in the morning (really, really, early in the morning…) definitely check it out. (And drag your partner (if applicable) out of bed, too - what could be more romantic than watching meteors leave their vivid trail across the sky? (At 3am. On a Saturday morning. In the damp and cold…) )

I found a great blog today - Adopt a Microbe. Delightful, friendly and usually death inducing microbes are all looking for a home (usually someone’s intestine or brain) and advertise for that special someone. Neisseria meningitidis (but you can call him meningococcus) is quick to assure you that he’s “carried in the noses and mouths of 5-10% of people, but I don’t make them sick.” Of course, he does have his downsides: “Most of the time, I cause meningitis and a special purple rash made of bleeding in the skin.” Oh yeah, and “I can also infect your blood.”

What a great way to get up to date with your friendly neighbourhood infections diseases!

A bill to legalise the cloning of human embryos for stem cell research today passed the Senate. Apparently, it’s also expected to go through the House of Representatives and hence, as best as I can gather, it will soon be legal to create cloned embryos for the purpose of extracting their stem cells to potentially create cures for a number of debilitating diseases, including Alzheimers and MS. DNA from an adult donor is transferred into an egg, which is allowed to mature for only 5-6 days, after which stem cells, versatile cells which are able to specialise to a variety of different tasks, are extracted which are compatible with their donor. This is therepeutic cloning”, and differs from reproductive cloning in that the embryo is never implanted and so cannot develop into a fetus (and, in all likelyhood, wouldn’t - cloned embryos in other animals have a very low successful birth rate).

Despite claims from some conservative Senators, I think this is a very positive result - although an egg is being fertilised, I don’t think there’s any issue of “destroying a life” here. And it puts Australia in a good position for being at the forefront of medical research.

Tomorrow between 5am and 10am Australian Eastern Standard Time (+1 hr if you’re on daylight saving), there will be a Transit of Mercury - where Mercury passes between the Earth and the Sun. Similar to a solar eclipse, when the moon goes between the Earth and Sun, Mercury will block out part of the sun’s light. Unlike a lunar eclipse, however, Mercury appears (and really is!) much smaller than the sun in the sky (about 1/200th of the size!) and so will appear as a small black dot moving across the face of the sun over about 5 hours. (Even though the moon and sun appear as almost exactly the same size in the sky, this is just a neat coincidence - the sun is actually much larger, but just enough farther away from the Earth to compensate and be able to almost exactly cover up the sun during a total eclipse.)

You can see an animation of what the transit will actually look like (you might need to hit Shift+Reload to see the image play again - I did, anyway). Because Mercury is so much smaller, you won’t be able to see this transit without a small telescope (not that you should be looking at the sun directly, anyway!) You should project the image from the telescope onto a piece of white card, and Mercury should be visible. Never, NEVER look at the sun directly through the telescope - you’ll fry your eyes, literally. UNLESS you’re lucky enough to have a sun filter - that blocks out most of the light, and you can observe the sun directly (also great for seeing sunspots and even solar flares!) There’s a good PDF factsheet with some more details of the transit and the setup you’ll need to observe it.

There are also various places around Australia (and beyond!) where you can observe the transit with professional astronomers - search on Google! If you live in Brisbane, come to the roof of the Parnell Building (Bldg 7) of the University of Queensland (just keep finding stairs that go up!) and we’ll have three telescopes set up - all welcome! Now, just cross your fingers for clear skies, because although transits of Mercury happen every 5-7 years, this will be the last one visible from Australia until 2032!

Beyond the intrinsic coolness factor, transits of Mercury and Venus help us better analyse planets and learn about their atmospheres (none of the other planets can have transits, since they orbit farther away from the sun than Earth!) It’s also by looking for transits of planets in front of distant stars that we have discovered many extrasolar planets - planets in other solar systems! Oh, and my final piece of trivia comes from ABC Science - it was a transit of Mercury which, ultimately, lead to the discovery of Australia by Britain - an observation of a transit of Mercury inspired Edmond Halley to suggest that transits could be used to determine distances between planets in the solar system, which lead to Captain Cook’s voyage to Taihiti to see a transit of Venus, which in turn lead to the British colonisation of Australia!

No science today, just a small bit of ego stoking I’m currently in a musical, a production of Anything Goes, produced by Queensland Musical Theatre. It’s a hliarious comedy, featuring songs of Cole Porter (if you’ve heard of him!) I play Lord Evelyn Oakleigh, a rather naive British lord with a fascination for all things American, but with a “dark and savage” secret (or, at least, he thinks it’s rather dark! )

We opened last week, and it’s been very successful so far. Best of all, the editor of the Arts and Entertainment section of the Sunday Mail, Brett Debritz, wrote a brief but positive review of it. In particular, he loved our leading lady, Hannah Macklin, who’s just fantastic - she’s got an incredible voice - and *sheepish grin* :

…the surprise package of the night being Joel Gilmore as Lord Evelyn Oakleigh. His treatment of Gypsy in Me was, on its own, worth the hike to Cannon Hill and back.

Woohoo! Who could ever say bad things about critics?!

So I’m a very happy man at the moment - life is good in so many ways!

Okay, this is a little Flash game that’s totally awesome - draw on the screen, and a little sled man then follows your lines as if going down a rather complicated (and usually bumpy) ski slope. It’s called Line Rider - check it out, and particularly some of the very complex machines that others have made!

Aside from just being very cool, it’s actually a simple implementation of a very cool concept - MIT’s Assist Sketch Understanding System and Operation (thanks, Brett!). In this video, they use a “smart” whiteboard to control a computer, and draw basic physics diagrams which the computer interprets and then animates according to basic laws of physics! It’s pretty impressive - my favourite is the final demonstration where he puts marbles on various slopes and gets them to land in a cup.

Do I think such a thing is actually useful? Well, it’s probably not so useful for introductory physics - we pretty much know what a cart does when it rolls down a slope. And it’s probably not so much use for a “real” engineer or researcher - it’s probably not precise enough, but it might be good for a “proof of concept”, quick sketch kind of application. But it might be good for making diagrams for mid-level students - connect up a bunch of springs, ropes and levers, and get an intuitive feel for what should happen. And if nothing else, perhaps it will inspire some more classroom enthusiasm!