illuminating science

I also meant to post this interesting story about debunking a girl who could supposedly read colours with her hands, and accepted Randi’s challenge. Needless to say, she didn’t make it into the history books as the world’s first proven psychic…

James Randi is an ex-magician who, among other things, works to debunk psychics. He has a $1 million dollar challenge out to any psychic who can demonstrate, under controlled conditions, that they have supernatural abilities. Prove it, and you get US$1 million; but if you’re found out, you get written up in his journal, publicised to the media and generally and widely ridiculed

So far, not one major psychic (in particular, famous TV psychics like John Edwards…) has agreed to take part in the test. You’d think if they really could read minds, they’d jump at the chance for an easy million bucks! Like Mulder, I’d love to believe there’s something more out there, but so far the evidence isn’t overwhelming. Check out his website for more details, and in particular watch the fantastic video that pretty much debunks Uri Geller, the famous “psychic” who could read minds, divine water and, most famous of all, bend spoons with his mind. Under controlled conditions, however, things aren’t quite so successful…

You know that scene in Men in Black, where they push the Red Button in their very cool car, accelerate to high speeds into the tunnel then end up driving on the roof to avoid the traffic? I thought it was a clever use of alien technology - but, it seems like it’s nothing that your ordinary sports car couldn’t do! According to this and many other sites, a Formula-1 racing car, which drives at speeds of up to 360km/hour (!), uses aerodynamics to generate a downwards force of 2.5 times its own weight. The air rushing across the top also pushes down, which means that there’s more friction so they can take corners at higher speeds without sliding off the track.

But the upshot of this is that they’re generating more than their own weight - so if they were to drive upside, the air is pushing it into the roof more than gravity is pulling it towards they ground. They could drive upside down! Of course, this is theoretical, and I don’t think that anyone’s actually tried it - but that’s not the point, is it? MIB might not be sci-fi after all…

Everyone probably knows that old science trick: how do you get a whole, boiled egg into a bottle whose neck is too small for it to fit? The answer, of course, is to light a piece of newspaper and shove it into the bottle. Quickly place your egg on top, and when the flame goes out - *thwup*, your egg is magically sucked into the bottle.

The was the activity being run by an established science demonstration group at a fair I went to recently. This demo was made famous (in Australia, at least!) by Julius Sumner Miller, of Why is it so?, a science show back in the 80’s, and countless kids (and adults!) have successfully duplicated the feat. (It takes a little work to find the right size bottle - the opening must be just “a little” smaller than the egg - 330mL glass juice bottle (Golden Circle, etc) work well!)

But one thing that’s a little hazy is the physics involved. The usual answer is that the flame uses up the oxygen in the bottle, creating a (partial) vacuum which sucks the egg in. Unfortunately, that doesn’t quite hold water - yes, the flame does use up oxygen in the bottle (that’s why it goes out eventually!) but it also produces new gasses - mainly carbon dioxide, but also some carbon monoxide (which is toxic to us). In fact, it can actually produce slightly more gas than it uses, which should push the egg out of the bottle! (One molecule of oxygen O₂ can become one molecule of carbon dioxide CO₂ or two molecules of carbon monoxide, 2CO.)

In fact, the real physics is what happens to gases when they heat up - they expand. Cool them down, and they shrink. You can see this by putting a tiny bit of water in a balloon, then putting the balloon in the microwave - the water turns into steam, which heats up and expands! (Just be careful - it can be hot! Also, don’t run your microwave too long when it’s almost empty, or it can damage it. Putting a saucer of water inside is a good idea)

So, when the paper burns, it heats up the air which expands. The extra air pushes the egg out of the bottle, and escapes out the sides - but the egg doesn’t fly away because gravity holds it down (it would be really cool to try this in zero gravity!) Then, when all the oxygen is used up, the flame goes out, the air cools down, shrinks, and sucks the egg into the bottle!

A fellow physicist, however, was a little skeptical - could the heat from a single match be enough to expand/contract the air enough to suck it into the bottle? So I did a little back of the envelope calculation: a match, apparently, releases about 1BTU of heat, which in proper SI units is 1000 Joules. Let’s assume that all that heat is released by a match dropped in the bottle. Say I have a 330mL=0.00033m³ bottle, and all the heat goes into the air of the bottle. The specific heat of air is approximately 1000 Joules per kilogram per degree and the density of air is approximately 1kg per cubic metre, at room temperature. So, I have 1kg/m³*.00033m³ = .0003kg of air, which receives 1000 Joules, and so increases by 1000 degrees Celsius!

Given that the volume of gas doubles when you double the temperature, this is more than volume change to suck the egg in. (There’s a subtlety here - the gas is initially at 300 Kelvin, a scale that starts at absolute zero but has the same spacing as Celsius. That means the temperature has tripled, and so does the volume.) Even allowing for the fact that some heat escapes from the bottle, less heat from the match, etc, this seems like expansion and contraction of gas, rather than “using up the air” is the true explanation of the “Egg in the bottle” trick.

Just when you thought insects could get any more amazing (you didn’t know insects were amazing?!) researchers have found that a certain type of wasp (non-stinging, no less!) has a sense of smell at least as good as a hound dog, and is able to be trained in 5 minutes to detect and respond to as specific smell! The result? The Wasp Hound, a plastic tube containing 5 wasps and a sensor that monitors their motion. When they detect a scent, they gather near the vent setting off the sensor! They envision the wasps as being used for detecting explosives at airports, toxins in crops, and even detect diseases by measuring chemicals in a person’s breath!

One neat thing is how they trained the wasps - “hungry” wasps are exposed to the desired scent, then fed sugar water. Wait, repeat two times and bingo - your wasps are fully trained! The wasps would have a 48 hour shift before being released to live out the rest of the 2-3 week lifespan.

And these guys aren’t the only ones doing insect research - another group has been exploring fitting a tiny transmitter to bees, which have been trained to detect explosives, drugs or other chemicals of interest. They point out that their bees are better than the wasps for open area searching, but not quite so good for crowded airports given that the bees can roam free… This all seems to be part of a growing field of using insects as “biological sensors” - guess it won’t be long before having computer bugs is a good thing!

This afternoon, I leave for holidays in New Zealand! We’re going hiking on the Milford and Routeburn tracks (the Milford track is supposed to be the most beautiful track in the world, and is certainly one of the most popular!)

That means (yes, again…) that I’ll be away from internet access for most of the time up to Christmas. I’ve written a few posts about things that I’ve been thinking about for a while and haven’t had a chance to post about yet, so there’ll be lots of interesting stuff coming. Honest. No, really.

So, good luck with your Christmas shopping, remember the 37 percent rule for choosing your presents, and if you’re feeling really geeky, try and decipher this Physics Christmas card. Merry Christmas!

If you thought mathematics wasn’t important, you haven’t met Dr Polster, a researcher from Monash University in Melbourne, Australia. He’s done a rigorous mathematical analysis to show that if you have a wobbly table, simply rotating it around its centre point - no more folded bits of paper under one leg! It’s based on an old but elegant proof for a square table, generalised to a rectangular table (with four legs - a three legged table rarely wobbles!)

Of course, there are so minor, technical details - the ground can’t be “too wild” (no more than about a 33 degree change in angle, and the table’s legs need to be at least half as long as its diagonal (basically, this may not apply for a short coffee table, but will be fine for a pool table!) And, of course, the resulting table won’t be level anymore - so it’s probably, in fact, not such a good solution for playing pool. But provided your ground is only mildly wonky, it’s probably not such an issue! His online paper paper is actually quite readable - I think that a confident senior high school student could probably work through a lot of it (although I haven’t read it all, yet!)

Pretty neat, I think!

Last night in Perth, Wester Australia, residents were treated to a fantastic site as the sky was lit up by a meteor burning up in our atmosphere. Ordinary meteors, or “shooting stars”, are actually just grains of dust that hit earth at high speed; the resulting air resistance heats them up so much that they burn up, giving off the light that we see. This meteor, however was apparently about the size of a basketball - meaning it gave off a lot more heat, lit up the entire sky, and created a thundering sound that shook buildings!

I saw a meteor something like that, although not quite as spectacular, when I was on an AstroCamp with the Brisbane Astronomical Society (and the PAIN Physics Club from UQ!) It was very bright, and had a green tail that stretched out behind it (which (I presume!) were tiny fragments burnt off and still glowing). I was really hoping it would come down somewhere nearby, but it kept going off towards the horizon, so we don’t know where (or if - it may have burnt up completely first) it actually landed.

I have to think it’s a once-in-a-lifetime, or twice at best, experience, unless you’re more than an amateur astronomer. Most of the time, we just have to settle for the best meteor showers we can find.

Great article on Wired News about links between the Dalai Lama and neuroscientists - the study of the brain. As I’ve mentioned before, I have great respect for the Dalai Lama. Whether one agrees with his religion or not, there’s not denying that he’s the most “rational” religious leader in the world, in that he has said publically he will gladly dispose of any beliefs that are scientifically shown to be false, regularly meets with scientists and actively encourages their work, and even attends international scientific conferences. (Are you listening, Pope Benedict?)

The article describes experiments which included measuring the brain activity of monks during meditation. They found that meditating on “compassion” (a specific type of meditation) produced specific changes in the brain, which demonstrates that meditation produces a “real” effect, although doesn’t tell us what that effect is. Other studies, however, have linked meditation to stronger immune systems and lower levels of cortisol, a hormone related to stress. Still more studies show changes in the physical structure of the brain.

This ties in with work of Jack Pettigrew, who measures “switching times” for “binocular rivalry” in the brain. An earlier post here describes it in more detail, but it basically refers to seeing the two sides of an optical illusion like the two faces/vase picture you might have seen. In a recent paper, Pettigrew showed that Buddist monks have significantly longer switching times than “regular” people, and that these times are greatly increased by meditation. Interestingly, this effect was for “one-point” meditation (focussing on a single object, basically “clear your mind”). For compassion meditation, no change was observed. (This suggest that this reinforces the validity of their results - it seems like a “real” effect due to a specific type of meditation, rather than just a reporting error from tranquil monks!)

I love the idea of science exploring Eastern philosophies (and something I love about Eastern teachings it that they lend themselves so well to this sort of thing - there’s very conceivably a real basis to them). One interesting development, however, is that the Dalai Lama was invited to give a keynote presentation (basically, the main talk!) at the Annual Meeting of the Society for Neuroscience. Many scientists strongly disagreed with that decision.

I’m not sure where I stand, so let’s be a physicist and consider some limiting cases. Most of the opposition was against having a religious leader speak at a scientific conference. If an Intelligent Design junkie were to speak at a conference on Evolution, I’d be dead against it - they clearly oppose the fundamental tenets of what is being taught. What if there was a priest with no scientific training but just wanted to talk about evolution? I think that’s the kicker - if they have no real “right” to be there; what are they going to contribute? Is the talk going to be constructive to the field, or is it going to go against the mainstream? The same argument applies to crackpots - I wouldn’t want them to speak at my conference!

If they’re going to talk about religion, then no, they shouldn’t be there. If they’re going to talk about philosophy, then it’s debatable - scientists talk about regularly at conferences about the philosophical/political aspects of science and research, and I think that’s valid. It probably comes down to the specific case. For me, the Dalai Lama has always seemed very open and unbiased, and I think he could offer a lot to directions in neuroscience, particularly in light of the current research.

Finally, I wanted to discuss the actual validity of the experiments. In some ways, they seem kind of crackpotty - why should I believe experiments claiming meditation strengthens the immune system over magnets curing cancer? And I confess, I haven’t seen the actual experiments, and nor do I know most of the researchers, so it could all be crackpotty. But I do know Jack Pettigrew, and he seems very much on the level; plus, the results are being presented at international conferences and in good, peer reviewed journals which suggests that they are supported by some, if not all, scientists.

But all that’s just my opinion. Regardless, I think that these are exciting new areas of research, and may well result in new understanding of our bodies and minds. As the Dalai Lama says “The purpose of meditation is not to cure physical ailments, but to free people from emotional suffering.”