A Talk to some National Youth Science Forum Students, 8/2/08

Where am I?

What’s going on?

These are not just questions I ask myself when I find myself up in front of a roomful of people, but questions I ask myself every day of my life. If I ceased to ask myself these questions, I would cease to be a scientist. I would become a non-scientist: or ‘muggle’ as we call them in the trade.

But, it is not enough to ask these questions. I could ask these questions and still not be a scientist. I might be a mystic, or an astrologer, or an internet conspiracy theorist.

What makes me a scientist is the way I try to answer these questions.

I haven’t been able to find this quote in the original German, but in English I think it is a perfectly dandy little quote. It is very measured and pedantically accurate, as a scientific quote ought to be.

It doesn’t say that everything else is rubbish: it says that everything else is poetry, imagination, two fine and splendid things. And it doesn’t rule out other means of knowledge: it doesn’t say there is no such thing as divine revelation; it doesn’t say that knowledge *won’t* be beamed directly into our brain by the Cephalopod Overminds of Omicron Ceti. But there is no possible way those possible means of knowledge can be considered to be ‘at our disposal’.

The only thing this quote lacks, as a description of the scientific way of trying to answer the question ‘what’s going on?’ is a definition of ‘experiment’. And here is the best definition of ‘experiment’ that I have come across:

An ‘experiment’ is just a small, controlled bit of ‘experience’. That’s all.

Because I endorse these last two quotes, I was moved to amend a third quote, which I found on a whiteboard in a student office:

The successful scientist and the raving crank are not separated by the quality of their inspirations. There is no mystical attribute of ‘quality’ that raises the scientist above the muggle. I would argue that most successful scientists spend a great deal of their time thinking up stupid ideas. Linus Pauling- another Nobel laureate- has said that the way to have good ideas is to have lots of ideas, and throw the bad ones away.

We decide which ideas are bad not by appealing to the Church, or the Central Committee of the Party, but by the procedure outlined in Feynman’s quote. That is what makes us scientists. What makes us ‘successful scientists’ depends on how you want to define ‘successful’.

You will note that these quotes seem biased in favour of what are called the ‘experimental’ sciences. The experimental sciences where you can take a small piece of the universe that you pretty much control- a test tube, or a nuclear reactor, or a bit of perfused llama liver- and do pretty much the same thing over and over again, with you controlling the conditions, until you discover a new physical law.

The historical sciences are things like astronomy, geology and biology where you are trying to make sense of somewhat larger pieces of the universe that are beyond your control. You can’t go out and blow up a star, or drop a few finches on an island and come back in a million years, or squash two continents together to see what will happen. But this doesn’t mean the historical sciences are not sciences.

In the historical sciences, you are observing experiments that nature has done for you.

You don’t have acccess to the experimental logbooks showing exactly what happened with the ancestor of the moa arrived in New Zealand, or when India started running into Asia, and you know that a lot of unique historical events, impossible to predict, went into the speciation of the moas and the exact shape of the Himalayas. So you can’t make the kind of exact predictions that you can in the experimental sciences. But on the other hand, nature has done a lot of these experiments and left them lying around.

The first principle that makes the historical sciences sciences, rather than history, is uniformitarianism. This means that we assume the same physical laws apply everywhere in space and time.

Our explanation of the stars have to use the same physics that we have figured out using light bulbs and nuclear reactors.

Our explanation of the moa has to use the same biochemistry and physiology that we have figured out using chickens and polyacrylamide gel electrophoresis.

Our explanation of the Himalayas has to use the same chemistry and rheology that we have figured out using test tubes and corn starch.

Now, this is just a guess, as in Richard Feynman’s quote. It is the simplest guess we could make, which is why we made it.

Einstein never said this.

[Note 1]

And William of Ockham never said this. (This is a late Mediaeval Latin way of saying the same thing; ‘entities must not be multiplied beyond necessity’).

We made this because it was the simplest guess we could make. But it is a good guess.

We have never found anything yet- out there among the stars, or back there buried under kilometres of limestone in the distant past- which cannot be explained using the physical laws we have figured out here and now. We have found things that can’t be explained by anything we actually see happening now, but we can postulate processes that make sense, that follow the same rules, that explain those things.

[Note 2]

This is just a picture to remind me of the dangers of hubris. [Note 3]

[Note 4]

Now, when I was growing up I was captivated by the historical sciences. I still am.

When I was growing up, a man named Carl Sagan was on the television talking about this incredible sweep of cosmic history, these countless galaxies like grains of sand,everything spewing out from an ancient singularity, and the accidents of history making Earth like Earth and Venus like Venus.

A man named Stephen Jay Gould was writing these articles in ‘Natural History’ about this incredible sweep of biological history, everything radiating out from a primeval protoplasmic globule, and the accidents of history giving us penguins and Staphylococcus aureus and whatnot.

And as for geology- well, my grandfather is a geologist. My father is a geologist. My brother is – now - a geologist. So I can never remember not knowing that I lived on a thin crust of rock trundling inexorably toward Asia, can never remember not having this vision of the continents scuttling about, mashing into one another and splitting up again, the accidents of history making the world we know.

So, why have I ended up in an experimental science, instead of a historical science? There are some trivial, historical reasons for why I ended up where I am – which may be the real ones - and a more profound one which I may have made up many years later.

[Note 5]

In Queensland twenty or twenty five years ago, the way to get a good score to get into university was to do all the maths and science subjects in years 11 and 12. But I wanted to keep doing German, which I’d done up to the end of year 10. And I figured from what we did in year 10 that biology was a subject that was easy enough that I could learn it all out of books by myself. So I did German instead of biology. Not that I can remember very much German now. Doof bleibt doof, da hilfe keine Pillen.

I’ve found that there have been times in my life when I have worked really hard at things, and at these times I have usually done well. First semester of year eleven was one of those times, and in first semester year eleven I topped the class in Physics - which I never did in any other semester, mind you - so I got this idea in my head that I would go on and do Physics.

[Note 6]

I didn’t have any concrete plans for where I wanted to go in the future and wanted to keep my options open, and when I got to uni I did physics, maths, chemistry, and- this was a mistake- computer science. I don’t know why I did computer science. I can’t remember. Maybe it was peer pressure. I was useless at computer science. I should have done something biological or geological...and then maybe I would have ended up in the historical sciences. But there I was in first year, not doing any historical sciences.

I found- this is just me- that while high school physics had been easy, uni physics was really really hard. This was mostly because I did not work hard enough at my maths. On the other hand, the physics pracs were great. I had a lot of fun in the pracs and did really well- but the exams were about as much fun as eating broken glass. Chemistry was the other way around. I found- this is just me- that the exams were easy, but the pracs were terrible. There was real, not metaphorical, broken glass everwhere.

So I ended my first year still uncertain, a little bit disspirited about how badly I had done in physics. And with no strong motivations, liable to be batted one way or another by small influences.

In between 1^st year and 2^nd year I read this book about Quantum Mechanics – an example of what I would now call the nitwit’s interpretation of Quantum Mechanics - and this inspired me to keep going with physics.

Second year was more of the same. Good pracs and bad exams in Physics, Bad pracs and good exams in Chemistry. I finished the year still uncertain, still at the whim of the winds of fate.

And in between 2^nd year and 3^rd year, I happened to read something about the discovery of the structure of DNA- I think it was this famous book- and I thought, aha! I will do biochemistry. Biochemistry really is the science of the 21^st century. It is where the big discoveries are being made that will cure cancer and give us potatoes that grow plastic instead of starch and let us genetically modify ourselves so we look like Klingons.

So in the next year I did 2^nd year biochemistry and molecular biology and some 3^rd year chemistry and maths units.

And the next year I did 3^rd year biochemistry and molecular biology and the rest of the 3^rd year chemistry units.

And over this time, I discovered that biochemistry pracs were even worse than chemistry pracs. With chemistry pracs, if they didn’t work, you usually could figure out why. Biochemistry pracs didn’t work for no reason. 50% of the time. Again, this is just me. I had thought molecular biology was all shiny machines that buzzed and clicked and spat out beautiful numbers, but it turned out to be all artsy-craftsy, full of messy polyacrylamide gels that never worked out properly. Of course, it is better now, I expect.

[Note 7]

And sometime around then, I happened to do a subject called ‘Advanced Physical Chemistry’ which was basically a reading list and a two-week project in a research lab. I did a project with A/Prof Ernie Senogles which involved playing with liquid nitrogen and fire, and it was a lot of fun. Exactly what I was doing there I’ll tell you after you’ve had another couple of years of science, because it will take too long if I start explaining now, and people will suspect me of trying a hard-sell to get you all to do chemistry.

But physical chemistry is more or less the exams of chemistry combined with the pracs of physics. And I decided this would probably suit me pretty well. When I looked at all I had done at uni, physical chemistry was pretty much in the middle, with wings stretching out to biochemistry in one direction and 1^st year computer science in the other.

Those are the trivial, historical reasons I ended up where I am, I guess.

Now for the deeper reason that I may have made up years later.

I don’t think I really picked physical chemistry because it was in the middle of the things I had done up until then, or because I was good at it. I think I picked it because it was a field where I could actually *do* those experiments and edge closer to truth. I realised I would rather work in a field where I got to do my own experiments, rather than look at the results of experiments nature had done for me. And the first of those experiments I met happened to be in this subject area in the middle of my degree, and involved playing with liquid nitrogen and fire. Because everything I had done in the lab up until that project, with the liquid nitrogen and the fire, had not really been an experiment, had been, in a way, something inherently pointless, because we already knew what should happen in the experiment, and it had been done so many times that the only possible explanation for an unexpected result was that I had stuffed it up. Real science is not like that; real science is doing experiments where you don’t know the answer.

So I went on and worked with Ernie Senogles for five more years, and came out with a PhD in physical chemistry and could call myself ‘Dr Chris’. During this time I went to a talk by Jean Marie-Lehn, who won the Nobel Prize for Chemistry in 1987. He said this:

What he meant was, once we understand what is going on with the physics, the basic ground rules of the universe, and once we have nutted out precisely what is happening with the sort of life we have on our planet that is all based on a very, very, very, small subset of the possible chemical reactions, we can go off and create things that are as complicated as life, but that use different chemistry. The buzzword ‘nanotechnology’ is a first little prefiguring of that 25^thcentury that Jean Marie Lehn is dreaming about.

After I finished my PhD, I went to the University of Sydney, and I worked there for five years, with some very interesting people, and some very smart people and some people who were scary beyond reason. And that was a very exciting place to work and we did a lot of good science.

But since I grew up in a provincial city, under balmy tropical skies, living in Sydney for me was too much like living in a box full of starving weasels, and I couldn’t possibly see myself living the rest of my life in *that* sort of place. [Note 8]

And then I came here, to the University of New England, and I’ll have been here four years in April, working with some very interesting people, and some very smart people and no scary people as yet. This is an exciting place to work and we’re doing good science here, and I intend to keep going until they pry my test tubes from my cold, dead hands.

So that is how I got where I am. And a bit about what’s going on.

But, if the truth be told, I find monologue really boring.

I think dialogue is much more interesting.

So, if we have time, I would love to answer some questions.

Notes

1: The font is Baskerville, an allusion to William of Baskerville in Umberto Eco’s ‘Name of the Rose’

2: The picture is ‘The Death of Smaug’. If you don’t get the reference, you need to re-read ‘The Hobbit’.

3: I was thinking that there was one problem that seemed obvious, after I had written that no mattter how far back in time we go we haven’t found exceptions to the laws of nature we’ve figured out, because we have these highly peculiar initial conditions for what we call ‘the universe’. I prepared a slide in case anyone asked me a question about this and tacked it on the end, but nobody asked me about it.

4: I was hoping someone would ask me about this picture in the question time. Nobody did. Looks a lot like Shoalwater Bay, doesn’t it? It’s not.

5: This is a picture of Pimlico State High School. I found it on a website in Brazil.

6: This is a picture of the Molecular Sciences building at James Cook University. Thanks to Maree Hines for sending the photo!

7: This is actually an experimental set-up where one of my current PhD students is doing something similar to what I used to do with liquid nitrogen and fire.

8: Technically, my fixed-term appointment was not renewed, and I was casting desperately about for a job somewhere, anywhere- South Dakota, Izmir, Bermuda... But I think my manifest lack of enthusiasm for the big city was one of the things that did me in.

O tempora! O mores!

And what extreme slackness on my part. Yet another zombie blog cluttering up cyberspace, alas!

Here are two more things I don't understand, which I will have a proper stab at real soon now:

(1) What is it with quantum teleportation? My gut feeling is that ‘teleportation’ is an illusion arising from us looking at things the wrong way.

(2) Ditto for the ‘collapse’ of a wavefunction.

What happens to these concepts in the De Broglie pilot-wave model? This is a model which can explain the mysterious double-slit experiments- where electrons (and neutrons, and helium nuclei) seem to interfere with each other as if they were waves *even if only one is sent through at a time* - in terms of each particle really being a particle but being guided by a 'pilot wave'. I find this much more satisfactory than wave/particle duality- which of course has no bearing on whether it is true or not.
De Broglie's abandoned this theory, but other people have been mucking about with it and optimising it from time to time. But, as a mere chemist, I don't really understand what they are saying.


“One singular deception of this sort ... is to mistake the sensation produced
by our own unclearness of thought for a character of the object we are
thinking. Instead of perceiving that the obscurity is purely subjective, we
fancy that we contemplate a quality of the object which is essentially
mysterious; and if our conception be afterward presented to us in a clear
form we do not recognise it as the same, owing to the absence of the feeling
of unintelligibility.”

- Charles Sanders Peirce, ‘How to Make Our Ideas Clear’

Granddad's Biography

Me Mum just sent me the link to this biography of my grandfather, Foundation Professor of Geology at James Cook University.

I was pleased to discover his philosophy of examinations:

I always felt that an exam should be a learning experience and, at a graduate level, all exams were take-home exams where a student could consult with any book or person. The catch, however, was that the questions had no answers, and the grade was based upon the approach to unanswerable questions. Students have come back later to tell me that this was the greatest experience they had in preparing them for the real world.

Things I Don't Understand: The Gibbs Paradox

I was told a while back that there is no such thing as entropy of mixing for ideal gases, and it makes sense to me.

In an ideal gas, the components of the gas don’t take up any volume, and they don’t have any specific interactions with each other.

If you start out with two ideal gases, A and B, in a container separated by a partition, and remove the partition, then gas A will expand into the whole of the volume previously occupied by A and B. Each molecule of A will have more options available to it than it had previously, and entropy will increase. Similarly, gas B will expand into the whole of the volume, etc. See, there is no entropy of mixing. There is only the entropy of expansion. If the volume of A equals the volume of B, this entropy of expansion turns out to be R.ln2, where R is the ideal gas constant.

But, let’s say we had equal pressure of gas A on both sides of the partition. We remove the partition, and gases A and A mix. Both of them expand, so we ought to get an entropy increase. But the pressure and volume and temperature of the final A + A system is exactly the same as the initial one: there has been no change, and the entropy of expansion turns out to be 0.

This is the Gibbs Paradox.

It bugs me because, let’s say we didn’t stop at one partition, but kept putting in more and more partitions until every particle was in its own little box, surely that would mean we had a system with less entropy?

Or not?

I keep looking for experiment data on entropy of mixing of gases, and all I find is people writing theoretical papers explaining the paradox away in different ways.

This one is particularly good, and says more or less- I think- that the thermodynamic entropy that we can use to do work with is not really a well defined function in the same way that energy is. It will depend on the things we have selected to characterise the system, and if we were to find out new ways of distinguishing particles that were indistinguishable before, we could exploit these to do work, and see an entropy change on mixing. This seems perfectly valid, but troubles me because I have been teaching first year in such a way that energy is an abstraction from entropy as a more fundamental concept. Which I will have to rethink without confusing myself totally.

Another paper that I have to read over again to try and start thinking clearly is this one, which is about the confusion between thermodynamic entropy and informational’entropy’.

So it seemed to me that when we remove the partition between A and A′, we had to be increasing the informational ‘entropy’ of the system, but maybe because there is no way to exploit this to do work, we haven’t done anything to the thermodynamic entropy.

I was talking about putting particles in boxes before, so I thought I should go all quantum and actually put our particles in boxes.

Let’s say we have some energy kT available for partitioning all our particles into translational states. These translational states will be separated by energies proportional to 1/a², where a is the size of the box. So the number of translational states available if the temperature stays the same but we double the size of the box doesn’t go up by a factor of 2, but by a factor of 4.

So I was thinking that there seemed to be a lot more ways of putting 2n objects in 4m boxes than of n objects in 2m boxes, and so there ought to be an increase in informational ‘entropy’ when we double the size of the box. Sure enough, when I looked up how to calculate the number of permuations there are a whole lot more permutations. But informational entropy is related to the log of the number of permutations. The log of the number of permutations at the end seems to be converging to twice the log of the number of the permutations I had in a box half the size... but it is converging towards one too slowly for the factorials I can do in Excel to cope. Is it going to go to one or not? Does ‘entropy’ of A + ‘entropy’ of A = entropy of (A+A)?

So I have to say this is something I don’t understand.

Next up: Quantum Teleporation.

What is Chemistry? A Preface to an as-yet unwritten Book.

Chemistry is the science of things that we can see and that we can control.

When I was young, I never gave chemistry a second thought. I loved the grand sweep of biological evolution, with its single unifying idea and its endless ramifications, every twig on life’s branch subjected to a neat exegesis by my idol, Stephen Jay Gould. I loved the vastness of space, the unimaginably gigantic and inhuman universe subjected to the breathless exposition of Carl Sagan. I was brought up in an atmosphere suffused with geology, and I cannot remember ever not knowing that I lived on a thin chunk of crust moving inexorably towards Asia. These, the descriptive sciences, the historical sciences, were where I lived. I wanted to know where I was; I wanted to know where I was going.

But...

It is not enough to know. If you actually want to do something, all of these sciences have serious flaws. You cannot crash galaxies together to see what will happen. You cannot evolve your own species of toothed whale. You cannot smear an archipelago onto the Pacific coast of North America. You can only watch, and collect data, and hope for a ‘natural laboratory’ which will test whatever hypothesis you have developed. The essential bits of the historical sciences, the most interesting bits, are inaccessible to our tinkering.

As I grew older, I grew to lust after the secret and paradoxical wisdom of the physicists, the world of Schrödinger’s cat and Lorenz’s butterfly and the modest goal of the Theory of Everything. Here again, I was driven by the desire to know what was going on. Once upon a time physics was a science where you could do things.

But now, alas, they have mostly been done. Now you need obscene amounts of money to do experiments and whatever result you get can be explained by the theoreticians. Is that falsifiability?

Actually, I must be honest. I cannot discount physics. I am a failed physicist. Somewhere among the ordinary differential equations I got lost, and fell off the mathematical billycart. When I say that the great achievements of what we call ‘Modern Physics’ ended in the 1930s, and that since then it is chemistry and its biological metastases that have transformed the world, you must discount it as sour grapes. Likewise, when I proclaim: ‘physics has given we chemists our tools, and now its job is done.’ Sour grapes.

Essentially, chemistry drew me in because it let me play with liquid nitrogen and fire.

If you actually want to do something, chemistry is the only science worth considering. With physics, we can control things, but we can rarely see them or even imagine them. We can see the subjects of the historical sciences everywhere, but cannot control them. Chemistry is the science of things we can both see and control.


Chemistry is called by some of its practitioners the ‘Central Science’, a term that I have always found naff. It is the ‘Human-Sized Science’.

A few more facts about chemistry:

Chemists are allowed to:

(a) Appropriate any part of physics they like and call it ‘physical chemistry’

(b) Invade and subvert any ‘softer’ science they like and turn it into chemistry.

It is no coincidence that so many Deans, Pro-Vice Chancellors, Vice Chancellors and Prime Ministers (e.g., Margaret Thatcher) have been chemists. Those whose job it is to manipulate matter naturally want to manipulate it wherever they find it.

The Electrochromic Effect

We are very coy and subtle folks, sometimes, we scientists. The other day I was skimming through 'Molecules and Radiation' by Jeffrey Steinfeld while preparing some lectures and came across this sentence:

"The Hamiltonian for the interaction of an atom with a static electric field [called the Stark effect after its discoverer, Johannes Stark (1874-1957); also called the electrochromic effect by other spectroscopists who did not like Stark] is just the electric-dipole interaction:"

Other spectroscopists who did not like Stark?

Why should other spectroscopists not like Stark?

My curiosity was piqued, and it did not take long for me to discover why.

The electrochromic effect it is!