Monthly Archives: August 2011

The end of days

S104 is really picking up the pace now – I’ve just submitted iCMA 48, with 93%. So that’s good then. And I’m zig-zagging through TMA07, which is due in on September 1.

Actually, it’s going quite well. I still have trouble deciphering some of the question wording, and suspect that they are set by people for whom English is not their first language, but you can’t have everything.

Sometimes, things just snap into place. You need to worry about them for a day or so, fret that actually, you’re rather stupid and you’ll never get this, and then it happens. A golden moment, a small firework in your mind, and there it is: enlightenment and understanding.

Question 2 (c)(i), I have the measure of you. I challenge you to a duel; pick your pistol. I’m confident, knowledgeable, and I shall have my satisfaction, sir.

I’ve very much enjoyed Book 7 – Quarks to Quasars. I’ve struggled a little with the specifics, such as energy levels, and the subtle effects electrons have on one another, not to mention the strength of the various interactions. But the concepts, the wider questions that border on the philosophical as well as the scientific – those, I love.

The feeling of stretching your mind so wide open that you feel it’s entirely possible there may be a permanent split is a heady rush. Have you ever stood on the edge of a cliff, or a very tall building, and had that momentary – just a split second – urge to throw yourself into the void? It’s a little like that.

The Universe started as a very dense, very hot mass of energy, then exploded and expanded. But how? Where did the energy come from? Was it always there, or did it just pop into existence? Lawrence Krauss maintains that yes, it came from nothing. I’m afraid I can’t accept that – which is why I shall keep reading, and watching, and learning.

And what about the “edges” of the Universe? What is it expanding into? Well, nothing that we can comprehend. The Universe has no edges, so to speak. It is everything. Or, it is everything in our comprehension. But that is not to say that there isn’t some”thing” out there beyond that, far beyond our comprehension, made of stuff that we could never know…

The more I learn about our Universe, the more fascinating I find it. I worried that I would lose the meaning of life if I was truly convinced of how insignificant we are – but, if anything, I have experienced the opposite.

Perhaps everyone has (or wants, or needs) to believe in something. I’m not sure. I don’t believe in a god, I know that now. This worried me for a time, as I see some of those I care for deeply, and their faith gives them strength and purpose. What would I have? I think my drive comes from a deep-seated desire to understand our Universe, to find out as much about it as I can. I believe it is within our grasp as a species, if we can manage not to destroy ourselves first. And what we find out may turn out to be completely unexpected.

And, I have faith in people. They are extraordinary.

Exploring Science

As this blog is following and documenting my adventures in science, it seems that I should say a few words about S104 Exploring Science for any prospective students of the Open University.

I’ll start by stating, in no uncertain terms, that this is a Very Difficult Course, particularly if there is no (recent) background in studying science or maths. This is not a light, adult-learning-style, interest-only course: it’s full on, in depth and requires an awful lot of hard work.

If any prospective students are not truly interested in science and really committed to learning, it will be extraordinarily difficult. I work full time, and I try to have a social life too – I have struggled to find the hours required for this course.

However, and I can’t emphasise this enough, S104 Exploring Science is absolutely bloody brilliant. It is Professor-Brian-Cox-jazz-hands-brilliant. Finding the time to study has not been, in any way, a chore.

Some aspects of the syllabus have been easier than others; some have interested me more than others. But overall, it’s fantastic.

Here, I need to pay tribute to my wonderful husband – I could not have done this without him. He has been supportive, interested, helpful (especially with the maths and physics) and he has become a very good cook. Joe’s patience is seemingly never ending, and I know he’s really proud of me. I am proud of him. And I am so grateful.

Anyway. Enough mush. Here are the facts, figures and ravings of an S104 Survivor.

For those thinking of starting S104, I would recommend that you do some reading first – partly to see if you really are that interested in science, and partly because it will give you a good base to build upon. I found Ben Goldacre’s Bad Science to be a great introduction to scientific method, and it’s a good read to boot. His blog is fab.

We Need to Talk About Kelvin by Marcus Chown is also a good read. One of the more wonderful moments of this course was when I realised, in a bolt of inspiration, that I actually understood what I had been reading about a few months earlier.

And as preparation for when you arrive, breathless and exhausted, at the bottom of the mountain that is Quantum Physics, give Jim Al-Khalili’s Quantum: A Guide for the Perplexed a whirl.

In fact, just read everything you can get your hands on, in the daily media, online and in journals such as New Scientist.

Before beginning, brush up your maths. Maths used to terrify me. It’s well worth doing the Open University’s freebie maths book to start.

Exploring Science is a nine-month course, and the course team recommends that a minimum of 16 hours per week is put aside for study. I have found this to be fairly accurate, albeit the study time is probably an average. Most people will find some topics require far less work, while others require much more (biology and quantum physics, please stand up!) .

There are eight books covering different topics, and although the order may seem slightly odd when you first see it – it does all fall into place:

  • Book 1 – Global Warming. This is a fairly gentle introduction to S104, and jumps feet-first into a subject that is bang up-to-date – climate change and all that goes with it.
  • Book 2 – Earth and Space. Geology and geological processes are introduced in part one, while in part two we leave Earth and venture out into the Solar System. Again, this is not too taxing, and is a decent way to ease you in.
  • Book 3 – Energy and Light. Physics-lite – I began this book reminiscing about GCSE physics, and remembering a surprising amount. By the end of the book I realised that this was Grown Up Stuff, leading my thoughts in directions they would never previously have contemplated. The maths began to pick up pace; and rather than becoming baffled and afraid, I developed a deep and abiding love for a beautiful and elegant discipline.
  • Book 4 – The Right Chemistry. Again, it begins with a recap of GCSE chemistry, then steamrollered into the kind of stuff that makes you wonder if, by the end of the course, you’ll be able to run your own meth lab. Fascinating. And if, like me, you were once afraid of the mole, this book will cure your fear.
  • Book 5 – Life. Biology. It’s the thickest book of the lot, and it’s stroppy with it. Life lulls you into a false sense of security, starting with the difference between autotrophs and heterotrophs, looking at prokaryotes and eukaryotes, before steaming into the minute detail of the reactions that make up photosynthesis. Think you know how plants make their food? Think again!
  • Book 6 – Exploring Earth’s History. An interest in fossils and geology will mean you sail through this book. It’s absolutely fascinating, and is a grand illustration of how absolutely everything in our Universe is connected. Our planet is a staggeringly beautiful and complicated place, and I am humble before it.
  • Book 7 – Quarks to Quasars. Mind-bending stuff. But give it time, read everything VERY carefully, more than once, and it WILL make sense. I promise. I found that writing notes in my own words was really helpful.
  • Book 8 – Life in the Universe. I’m not there yet. But the book promises to pull together all the aspects of S104, enabling us to build a complete picture of how the separate disciplines tie together. All branches of science are connected, and feed into each other. It will be good preparation for the End of Module Assessment.

Everybody’s techniques for studying are different, but this is how I approached Exploring Science. As I read through each chapter, I highlighted relevant concepts, ideas and facts, making notes in my own words. I also, as you have probably gathered, began this blog. It is, in part, a method of finding out if I’ve fully understood what I’m learning: if others understand my tales and explanations, it’s a good bet that I have.

Talk to your loved ones: bore them silly! I am lucky to have a husband who is almost as fascinated by this stuff as I am, and many of my friends are crazy about science. (I thank you all so much for listening, reading and generally being interested. I love you guys!)

Use the tools the Open University gives you: do all the activities, because they really do consolidate your learning, as well as being good fun in many cases. The questions dotted throughout the text are brilliant, testing your knowledge and understanding before you come to do the assessments.

And speaking of assessments: at the end of each book, you are required to complete an iCMA (interactive computer-marked assignment) and a TMA (tutor-marked assignment). These contribute to your overall mark, as well as helping to pull together everything you’ve learned.

A good tactic for the iCMAs is to write them out in rough before you enter the answers. My first one was pretty shameful, purely because I hadn’t read the instructions properly! In my excitement at starting the course, I achieved only 80%…

For the TMAs – read the questions really, really carefully! Sometimes the OU examiners do not use language in the way you may expect… I found that leaving the TMAs right until the end of the book meant that I was a little stressed about getting them in on time. The questions helpfully tell you which chapters you should have finished before attempting to answer – I would advise that the TMA is completed as you go along.

Use your tutors, that’s what they’re there for. They are a great source of support, if you’re lucky enough to get a really good, dedicated person. The tutorials are also a good source of support, as well as helping you meet other students.

Use other students too: the tutor forums can be helpful, if you get a good group – or join the S104 group on Facebook. I’ve made some lasting online friends through that, and it’s made me laugh until I cry on more than one occasion. You are not struggling alone.

And finally: enjoy it! It’s been a fantastic experience, and I’m genuinely sad at the thought of the course ending (although I cry at the news, so don’t let that be a measure of normality…). Good luck, and remember:

“What we have learned is like a handful of earth. What we have yet to learn is like the whole world.” Avvaiyar, Indian poet-saint.

What flavour are you?

Chapter 7 of Book 7: Quarks to Quasars begins with a quote from Lords and Ladies, a book by the most marvellous Terry Pratchett. This pleases me immensely – not just because I am a big Discworld fan, but for reasons that will hopefully become clear.

“It was here that the thaum, hitherto believed to be the smallest possible particle of magic, was successfully demonstrated to be made up of resons (Lit.: ‘Thing-ies’) or reality fragments. Currently research indicates that each reson is itself made up of a combination of at least five ‘flavours’, known as ‘up’, ‘down’, ‘sideways’, ‘sex appeal’ and ‘peppermint’.” Terry Pratchett

Firstly, this description of sub-magic particles is not so far from our description of subatomic particles. Including the flavours.

Secondly, “reality fragments” is not just a poetic way to describe the fundamental particles that make up the matter of the Universe, but is also pretty accurate. Reality fragments can be put together into larger and larger particles, as the stuff of the Universe is created in star factories.

In our world, until fairly recently (50 years ago or so), it was accepted that the Universe was built from protons, neutrons, electrons and electron neutrinos. Electrons and electron neutrinos, together with their antiparticles (everything has an equal and an opposite), are indeed fundamental particles. They cannot, as far as we know, be broken down further.

Electrons and electron neutrinos are in the lepton family, along with four other fundamental particles: the muon (about 200 times heavier than an electron) and its associated neutrino; and a tauon (about 3,500 times heavier than an electron) plus its neutrino.

So, there are six flavours of lepton. The electron, the muon and the tauon, which all have a negative charge, plus their neutrinos, which are neutral. And just to really confuse matters, there are also six antileptons, with a positive charge but the same mass.

The word “lepton” comes from the Greek leptos, meaning “thin” or “lightweight”, which is reasonable really when you consider just how tiny these things are…

So are these the only fundamental particles? No. We now know that if two nucleons (a proton or a neutron) are picked apart, smaller bits fall out.

Now, let’s give the nucleons another name – just as a test of memory. Protons and neutrons are examples of hadrons. They are not the only hadrons – there are also baryons and mesons.

What makes up hadrons? Quarks!

(As an aside: if you google “quark” in images, you get the Star Trek character. This pleases me.)

This is where it becomes really fun, and has led me to believe that particle physicists are a bunch of hippies at heart. It wouldn’t surprise me if they loaf around smoking pot and drinking absinthe while pondering the nature of the Universe (and there’s nothing wrong with that). You see, quarks, too, have flavours. Sadly not “peppermint” or “sex appeal”, but Terry wasn’t far off.

The quark flavours are: up, down, charm, strange, top and bottom (or, on a particularly fuzzy day, top and bottom are known as “truth” and “beauty”). The up, charm and top quarks have a charge of +2/3e and the down, strange and bottom quarks have a charge of -1/3e. And don’t forget that each quark has its corresponding antiquark…

A hadron can consist of three quarks (a baryon), three antiquarks (an antibaryon) or one quark and one antiquark (a meson); and it always has a whole number charge, so you can determine the recipe.

For example, a proton has a charge of +e and is composed only of up and down quarks. The only way to produce a net charge of +e with up and down quarks is with the recipe up, up, down (uud): 2/3e + 2/3e – 1/3e = +e.

Simples!

It is now accepted that these are all fundamental particles; that they cannot be broken down further. However, particle physics is moving at lightning speed, and boundaries are being pushed all the time, so who knows what else will turn up?

It is incredible that we have drilled down into the very fabric of the Universe, and pulled out particles that are so small they are incomprehensible. Much like trying to imagine the immense distances between the stars, numbers and sizes become almost meaningless at this point, and it’s much more helpful to think in abstract terms.

Perhaps this is why physicists have come up with such whimsical names for the particles… at this stage, it may as well be pixie dust!

Particle wanted: dead or alive

Book 7 – From Quarks to Quasars – is going exceedingly well. I was not quite sure what to expect from a crash course in quantum physics, as it’s a subject I’ve long been fascinated by. However, with great fascination comes great bafflement, so I was expecting to be totally befuddled.

As the great Niels Bohr said: “If quantum physics hasn’t profoundly shocked you, you haven’t understood it yet.”

It is a source of some pleasure that in fact, I’m not struggling with this book at all. It’s heavy going, and there are some difficult concepts – not to mention some downright weird concepts – but with really thorough reading it is all making sense.

Why do some concepts come so easily, while others seem so difficult? Some people struggle with ideas that others find simple; for me, that is engineering and abstract concepts. Quantum physics, though, makes perfect sense to me. I don’t know what that says about the way my brain and mind work…

According to the Book, most people find it difficult to come to terms with the idea of quantum indeterminacy, with Albert Einstein himself finding the idea abhorrent.

I can understand that: Newton’s world was ordered and completely predictable. I like order; I thrive on it, in fact. Some of my favourite things are lists. But quantum uncertainty makes perfect sense to me.

One cannot say for certain exactly where an electron is in an atom and simultaneously know its velocity, so instead of the “classic” atomic model with electrons orbiting the nucleus, Schrödinger (he of the cat – and more on him later) proposed a new and improved model. The nucleus is surrounded by a fuzzy cloud of electrons, denoting the range of possible positions the electrons may occupy.

"Classic" model of the atom

So, why can one not predict the position and velocity of an electron? Theoretically, an experiment could be devised to measure its position or velocity, but can they be measured simultaneously?

Schrodinger's model of the atom

The Heisenberg uncertainty principle says “no”. If you know the exact position of a particle, you cannot know anything about its velocity at the same time. The reason why is actually rather simple, and makes perfect sense (once you understand how energy levels work in atoms…)

To measure something, you have to “see” it. And to “see” it, you have to shine a light on it. But by shining a light on an atom (which is where the electron we’re looking for is) one of two things will happen

  1. A photon from the light may be absorbed, causing the atom to change energy levels. The quantum state of the atom will have changed, and the electron will no longer have the same position or velocity.
  2. The photon may not interfere with the atom at all. In which case nothing has been measured.

This is the basis from which comes the adage that the act of observation changes the observed. This is certainly true on a quantum level, and true of a subject that knows it’s being watched.

(It’s a good example of how armchair psychologists and philosophers grab an idea from quantum physics and give it a little tickle, without fully digesting the concept!)

The above aside brings me neatly back to Schrödinger and his beknighted cat. It’s a wee niggle of mine that much of the populace seize on Schrödinger’s thought experiment and bend it to a vague philosophical notion along the same line as a falling tree making a sound when there’s nobody there to hear it. Or not, as the case may be.

Quantum cat: observation fail

It’s not as simple as not knowing for sure if the cat in the box is dead or alive before you open the lid. (And if they’re my cats, there’s no uncertainty at all, because they’d be screeching threats through the lid.)

The cat in the box is awaiting its fate – a possible death by poison. A vial of poison is positioned in the box, along with a radioactive isotope. If the isotope decays, the poison will be released by a trigger system. However, here is where quantum uncertainty comes in: the isotope may decay immediately. It may not decay at all. And all the possibilities in between. But the point is that until the box is opened, nobody knows whether or not the isotope has decayed, and so whether or not the cat is dead or alive.

The isotope now has a wavefunction describing two states: decayed and undecayed (because we can predict the probability of its state at any time, but not its actual state).

Is this all making sense?

(Schrödinger had also had enough of quantum weirdness, which inspired him to anger animal rights activists the world over in the first place.)

He then carried the theory of quantum uncertainty a little further: the cat is also made of atoms, and is a quantum system (a huge and complicated one, but a system nonetheless). So, stretching this, the cat must then also have a wavefunction describing a live cat and a dead cat, using probabilities based upon the probability of the isotope’s decay – because the cat’s fate was now bound inextricably with that of the isotope.

Clearly, this is silly. And Schrödinger knew it, which is why he challenged the upstarts Bohr and Heisenberg and their quantum theories of oddness.

It is resolved though: the cat is shut in a box. We can have no knowledge at all of the real state of the cat: probability is just a string of numbers. Without measuring reality, we cannot describe it – so we do not try. When it comes time to open the box, we can use the probability of the isotope’s decay to predict the probability of the cat’s state, but beyond that – nothing.

There’s an excellent book: “Quantum – A Guide for the Perplexed” by Jim Al-Khalili. It explains a lot of difficult concepts really well.

I hope I’ve made a start. It makes perfect sense to me, anyway!

Stay tuned for nuclear decay…

Interlude

I’ve been on holiday to the beautiful, wild, staggering Scottish Highlands. Achmelvich, Skye, Poolewe and Applecross, to be precise. So there has been little blogging, and a small holiday from studying.

Tomorrow, I shall be blogging about many things quantum. But for now, I shall leave you with this quote, spoken about physics and chemistry, but true of all things:

“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.” Marie Curie, Polish-French chemist and physicist, and winner of two Nobel prizes.

Peace out.