27 June, 2006

What's hot in the world of science?

I've just discovered the nifty new "Most Popular Now" page on BBC News, which shows you which stories are getting the most attention worldwide, or region by region. You can even check by subject - for example, as I write the top science and nature stories involve a 'chameleon' snake and another depressing set-back for the EU emissions trading scheme (though it's Germany, rather than the UK, in the dock for once).

Wouldn't it be good if instead of the general public, you could discover what was exciting scientists? Nature offer a list of the month's ten most downloaded articles, but sadly (and not surprisingly) biomedical stuff seems to dominate to the exclusion of all else. Better is the Top25 portal at ScienceDirect, where you can search by subcategory and individual journal (I think you can at least access the abstracts of the listed papers without a subscription).

This is a very crude tool, because a better measure of whether a particular paper has excited scientists is how much they use the ideas and results to guide and augment their own work, which is measured by citations. Tracking who is citing whom is a bit more difficult than counting downloads or page hits, so freely available information seems a bit limited: Thomson Scientific runs in-cites, which offers the top three 'hot papers' published in the last two years in various fields, and also a list of 'super-hot' papers which seem to be garnering special attention. However, although this is interesting, I don't know how much use it is for me as a scientist - within my field I can learn a lot more by getting down and dirty at Web of Knowledge, and searching for papers in the Science Citation Index, which cross-links every paper published in the last 25 years to the ones it cites and the ones it is cited by. Having an internet connection on my desk is a mixed blessing, but every minute of my day that is wasted through mindless web-surfing is more than compensated for by access to that sort of information.

26 June, 2006

How to stop worrying and love your mapping project

As I may have mentioned, prior to my holiday my life was taken over by marking and viva-ing a breeding population of undergraduate mapping projects. These projects are a major part of the third year, and are a required component of any certified geology degree, and in a week’s time, I’m heading out to the Cantabrians in northern Spain to get some of next year’s students started on their 30 days in the field. As a preparation for that, I’ve written a list of tips and pointers collated from weaknesses (and strengths) I perceived in the projects I marked; the comments of the external examiners at the exam board meeting I sat in on last week; and reminiscences of my own mapping project, way back in the summer of 1999, which I used to guide my marking (as per usual, the guidance I was given by the department was a little…. sparse). It’s probably not of particular general interest, but you never know.

The aim of mapping

The ultimate aim of the project is not the map. Your goal is to uncover the geological history of the mapping area, principally:
  • The sequence of deposition of the different formations, and the environmental and tectonic changes which have produced these distinct rock types.

  • The structures (faults and folds) which have led to the present distribution of the different formations, and the tectonic events which produced them.

A good map is essential for developing this understanding, but if you confine your fieldwork to simply colouring the distribution of outcrop, you’re making it difficult for yourself.

Thinking and hypothesising in the field

There are various scales of observation to consider when you’re recording the geology at a particular locality, from whole outcrop to hand lens. When mapping, you also have to think about the biggest scale of all: regional context. As well as the obvious (e.g., ‘this is 200m downstream from the last locality’), you should always be asking yourself, what’s going on at this locality compared to the last one you saw, and others nearby? Can you explain any changes in rock type, or structure? It is especially important to properly record such observations. If a formation you don’t expect suddenly appears, note down that it’s unexpected. Record and sketch any ideas you might have about what’s going on, and what you might find at the next outcrop if your idea is right. Then go and have a look. Even if you never do field geology again, this is great experience of doing real science.

Field slips as working documents

Field maps are not something to passively colour in outcrop on; you should be trying to infer boundaries, and drawing them on, as early as possible (the same is true of faults, folds etc.), preferably as you are mapping them. Doing this turns your field slips into a powerful tool to guide your mapping, allowing you to visually check, whilst you are still in the field, whether what you are observing makes geological sense, and highlighting areas that you will need to concentrate on to sort out what’s going on. It’s far easier to do something about problems and missing data out there, than months later back home.

Annotation of your field slips is also important – if you’re inferring a boundary due to a break in slope, or a change in vegetation, then record this on your field slip. If you have observed a good exposure of a fault plane, or an unconformity, highlight it. All of this tells a marker that you are doing geology, rather than colouring in.

Don’t be a slave to the literature

In your final project, you will be expected to justify all of your conclusions and interpretations in terms of what you have actually observed in the field. It's fine to compare what you have seen to what is stated in the literature, but published research is not a substitute for your own observations – even (especially!) if they disagree. Like any geologist, the authors of papers about your mapping area have pieced together the history of the area from incomplete information, inferring boundaries and structures where there was no exposure. What is more, their research usually encompasses a much larger area in far less detail, meaning that the observant undergraduate might well see features, structures, and even outcrop that they did not. This new information might change your interpretation completely, indicating that in your area at least, things were different from the published interpretation (you should also bear in mind that general conclusions for a larger region may not be a good fit for your specific area).*

Observation and interpretation in your notebooks

Third year students shouldn’t need reminding about separating interpretation from observation, but they do need to be aware of the biggest enemy they will face in their 30 days in the field – boredom, the effect of which is to make people forget about the observing part and move straight on to the interpretation.

Day 28, and you come across an outcropping of limestone. It looks like a formation you’ve seen a hundred times by now, it’s about where you expect it to be. You write in your notebook, “Locality 278. Exposure of Intractable Limestone Formation,” record any structural information, and move on. The only problem is, assigning a formation is an interpretation, and it has been written down without recording the lithology, fossil content, and other observations which explain why you think it is that formation. Months later, you start to suspect that at that outcrop it was the Inscrutable Limestone instead of the Intractable Limestone. If you have recorded your primary observations, you can check this – you may see that at this particular outcrop you didn’t see the fossils characteristic of the Intractable, making it possible you misidentified it. If you just have a formation name, you’re stuck.

So work hard to maintain the quality of your notebook. After 30 days, you can’t possibly remember everything you’ve seen in your area; you will need to have it all written down so you can refer back to it.

What you should (and shouldn’t) be doing in your evenings

There is a growing trend for students to put very little on their maps, and sometimes even in their notebooks, in the field, only to waste hours reproducing immaculate versions of what they have seen in the evenings. What you will get for all this effort is suspicious markers, who want to see evidence that the field slips are being used, as I have already discussed. Filling in as much information as possible as you go means that in the evening all you should have to do is make sure that everything is legible and inked in, freeing up time for what you should be doing, namely thinking. Did you understand what you have seen today, or are there still areas you don’t grasp? Does it fit in with your current understanding of the whole area? It goes without saying that you should write down these thoughts in your notebook.


Ah, the term which strikes fear into the heart of every undergraduate - which is all the the more reason not to leave it until you’re writing up before thinking about them. From the very beginning you should be devoting some of that evening thinking time to sketching cross-sections. Amongst other things, this is another check on whether you’ve mapped things correctly – projecting things into the third dimension can reveal problems which aren’t immediately obvious in plan view.

Although within a week you should have enough information to produce a reasonable first stab at a section through your area, a fully accurate one will require a lot of structural data along the line of section. It is a really great idea to select a sensible cross-section line (or lines) before you finish in the field, then take a day to traverse it (or them), checking that what you see agrees with your map, and that you have enough structural data to properly constrain things. Again, this can reveal problems with your map which are much easier to fix out there than back here.

Sketches or photographs?

Both. If you have a digital camera, it’s very tempting to rely on cold hard optics rather than your own sketches, and it’s certainly true that a photo can record more detail, more accurately, than all but the best of us can manage with a pencil. But there is a lot of interpretation involved in the process of sketching – you are picking out and highlighting the most important features of the outcrop. You can’t do this when taking a photograph, which means that when you look at again it’s very easy to forget what it is supposed to show. A photo cannot replace a sketch, but it does complement it, and vice versa.

Small-scale tells us about large-scale

Because rocks tend to deform at all scales, clues to the overall structural style of an area can often be found by looking at features of smaller scale folds (e.g., shape, vergence) and folds (e.g., orientation, sense of displacement from slickensides). Detailed measurement of these features can be very useful.

So endeth the lesson.

*I didn’t get anywhere with my own mapping in North Wales until I folded up the BGS sheet for the area and put it at the bottom of my bag for the rest of my trip. It just wasn’t at a small enough scale to properly represent all the details I was finding – for example, it had a lot of random faults running through my area, when I thought there was a lot more regularity there. As it turned out, there was.

25 June, 2006

What makes a good science teacher?

Not content with assimilating science-inclined bloggers left, right and centre into the looming Scienceblogs collective, Seed Magazine also regularly demand tribute, asking them all to answer weekly questions in their own idiosyncratic styles (see here for previous examples). This week’s asks, ”What makes a good science teacher? All the responses will be eventually collated here, but as this is a question that I have been struggling with for the last 10 months or so, I thought I’d just point out some common themes in the answers so far, and add my perspective on them.

Corturnix at A Blog Around the Clock says that one of the keys is to know your subject.

Knowing your material inside and out, at least a hundred times better than the students or the textbook - that certainly helps, not just in answering potential questions, but also in the degree of self-confidence one brings to teaching.

This is especially important for me, because I’ve found it almost impossible to use pre-written notes effectively; even if I have them, once I've started talking I forget that they are there. And whilst this potentially leads to a much more flowing lecturing style, it’s also much easier to start rambling if you don’t know the material inside-out.

More importantly, I’ve found that you can understand a concept well enough to use it every day, and that still doesn’t mean you can teach it effectively. Your route to understanding something often involves all sorts of mental short-cuts which make perfect sense to you as a (relative) expert, but will quickly lose a novice. Spotting these is very important; as Jason Rosenhouse at EvolutionBlog puts it:
The key to good teaching is an ability to put yourself in the position of someobody learning the material for the first time.

Mike the Mad Biologist agrees:
A good teacher has to know what students don't know.

Or, as someone told me to my chagrin on a field trip (regarding some lectures I’d done the previous term):
You came across as knowing what you were talking about, but that didn’t mean we always understood it.

Sometimes that isn’t just about poor explanations though, it could be that the students can’t work out what the point is. As the Evil Monkey opines at Neurotopia:
If I had to decide what makes a good science teacher, it would be the ability to demonstrate how experiments fit into the proverbial "scheme of things". Nothing kills interest in science faster than 1. not being able to accurately relay the structure of the big picture and 2. just tossing a bunch of apparently random experiments at the students and expecting them to figure out how the pieces fit together. You wouldn't attempt to put a jigsaw puzzle together in the dark, would you?

Concurrently, at Good Math, Bad Math, MarkCC says (about maths teaching, but I think this is generally applicable to all sciences):

But it's very easy to get caught up in the abstraction, and forget why you're doing it. Good math teaching is a subtle act of balance: you're studying abstractions, but you need to keep the applications of those abstractions in sight in a way that lets your students understand why they should care.

Case studies, drawing examples from published research to show how the concepts you’re talking about are tools, with clear uses, are important in this regard (in geology, I’m helped greatly by the fact that it’s not usually too difficult to link even the most theoretical stuff to the ‘real world’). In lectures, narrative is a great way to hold attention: show a problem which scientists set out to solve, before showing that the concepts you’re teaching about were essential in solving it. Such a structure also naturally incorporates insights into how science works, which Dr. Free Ride at Adventures in Ethics and Science thinks is the most important thing of all:
In the grand scheme of things, the most important knowledge for the science teacher to transmit has to do with methodology rather than a laundry list of facts (especially since lots of the facts get updated). And the methods of scientific inquiry are not completely divorced from common sense. Building on the continuities between the two is a good way to get the kids who may not grow up to be scientists a good appreciation of how science works.

And I’ll give her the last word too, as she admonishes those of use who fall back on the old ‘science is hard’ shctick to compensate for the fact that only the really bright ones seem to follow you.
… if you're a teacher, your goal when you walk into the classroom should be to teach all the students whatever it is you're charged with teaching them. We don't always meet our goals, but dammit, at least try!


23 June, 2006

UK's green credentials questioned again

From New Scientist:

MANY governments, including some that claim to be leading the fight against global warming, are harbouring a dirty little secret. These countries are emitting far more greenhouse gas than they say they are, a fact that threatens to undermine not only the shaky Kyoto protocol but also the new multibillion-dollar market in carbon trading.
The article describes some work from the Insitute for Environment and Sustainability at the European Commission Joint Research Centre (Peter Bergamaschi, the lead researcher, has a home page here - although there is no information on this story at either of these links yet). The research is based on direct measurements of atmospheric methane concentrations around the globe, which are then combined with atmospheric modelling.

[Using this technique] scientists say they can calculate a country's emissions independently of government estimates. Bergamaschi's calculations suggest that the UK emitted 4.21 million tonnes of methane in 2004 compared to the 2.19 million tonnes it declared, while France emitted 4.43 million tonnes compared to the 3.01 million tonnes it declared.
Such underestimations are significant in the context of both the Kyoto Protocol and emissions trading schemes:

"Now that money enters the picture, with the Kyoto protocol rules and carbon trading, so also can fraud. There will be an incentive to under-report emissions."

Cynical as I am, I'm ready to give the benefit of the doubt in this instance - estimating emissions is not an easy task, especially for methane where the major sources are landfill sites and peat bogs rather than power stations (although it seems that the government is not exactly jumping over itself to try and improve the monitoring). The real test will come now that these results have been publicised - will the government admit the possible underestimation and revise their figures? I'd also be interested to know whether a study of carbon dioxide would produce similar results.

21 June, 2006

Are we running out of Uranium?

I’ve just seen this post over at Bunsen Burner which discusses the case for new nuclear build, and which I heartily agree with (mainly because I’ve come to the same conclusions, albeit in a less concise manner). Whilst it’s always nice to see people agreeing with me, I was interested by the following sentence:

There is only so much uranium in the world and even with reprocessing this power source will run-out at some point. So wouldn't the money better be spent on something a bit more long term?

Which got this comment in response:

There is a significant body of work that disputes your conclusions about the global uranium supply.

Does this mean that somebody somewhere is seriously arguing that uranium supplies are renewable? Entertaining as that would be, it would seem not. Instead, the the link in the above comment is a post responding to claims (in a Guardian article which I missed) that the uranium supply is already on the verge of being exhausted. So, whilst the comment is a slight over-reaction in the context of this particular post, it does raise an interesting issue. So what are the facts?

A recently published IAEA report (home page here - except for the one exception listed below all the figures I use come from here) estimates the known inventory of uranium extractable at current market prices to be about 4.7 million tonnes, and total estimated reserves to be about 35 million tonnes. An estimate from what could be regarded as the other side of the fence is provided by van Leeuwen and Smith, whose work I’ve referred to before, and who estimate 4.3 million tonnes of ‘useful’ reserves with little hope of new major ore bodies being discovered (Chapter 2 from here). So a lower limit of about 4.5 million tonnes seems well-supported; estimating an upper limit is fraught with the usual difficulties you get when guessing how much you haven’t discovered yet, but we could probably take 35 million tonnes as an optimistic upper bound (I’m not sure how these figures would be affected by economic considerations, but it looks like it includes stuff which cannot be profitably extracted at current prices).

Production and Usage:
The IAE report says that mining produced 40 000 tonnes of Uranium in 2004. About 67 000 tonnes was actually used in nuclear power stations, with the shortfall coming from ‘secondary sources’ (stockpiles, reclamation from decommissioned nuclear weapons, some reprocessing). These secondary sources are being depleted, so we’re going to rely more and more on primary production in the future.

Doing the sums, if it’s all coming from primary sources the supply will last 65-500 years at the present rate of consumption. But demand is expected to increase to as much as 100 000 tonnes/year by 2025 (based on proposed new build, which probably doesn’t include any hypothetical new UK stations), reducing the supply lifespan to 45-350 years. That is, if we can actually supply 100 000 tonnes/year; by 2010, up to 30 000 tonnes/year may be added by mines currently being or planned to be developed. This still leaves a bit of a shortfall, but we’d have 15 years to address it.

So, on current trends it would appear that there’s no real supply problem, at least not in the lifetime of the next generation of power stations. But the key phrase is ‘on current trends’, because the whole point is that there’s a lot of debate (and hence uncertainty) over the future of nuclear power. For example, if we embark on a massive nuclear building program to replace fossil fuels, all these sums get skewed towards rather lower supply lifetimes. This would be a concern, but not an insurmountable one; my chief objections have always been, and remain, the questionable effectiveness of the nuclear option in solving the problems of greenhouse gas emissions and energy security.

12 June, 2006

On hiatus

Right, I'm off for a well-deserved break, to enjoy the fabulous geology (sorry, scenery) of the fair Isle of Skye. When I'm back, hopefully my life will be less mad and I can get back to posting more regularly.

Permian crater in Antarctica...maybe

I was way too busy last week finishing off marking and vivas to comment on this story about the possible discovery of a 300-mile wide impact crater which seems to be about the right sort of age to have possibly contributed to the Permian extinction, an event 250 million or so years ago which wiped out about 90 % of all species on Earth (see here and here for some discussion and links).

The method is indirect, using the GRACE gravity satellites (which I've mentioned before) to find a positive mass anomaly beneath Antarctica which seems to indicate a massive upwelling of material from deep in the Earth. This has been linked to a ring like structure beneath the ice (pictures here).

Dean Armstrong points to a Nature article which emphasises that there is as yet little direct evidence of this being an impact structure. In particular there is little evidence in Antarctic Permian rocks (at least, those which aren't under lots of ice) for any sort of impact - no ash flows, impact breccias, or megatsunami deposits which can be found around the KT impact site. Which leads to another thought: the researchers tried to make a link between their putatative crater and the mantle upwelling, and the fact that this is close to the rifting event that began the break-up of Gondwana. If there is no crater, this may not be support for the (controversial) idea that large impacts can cause rifting, but instead could be telling us something about the internal processes that triggered that rifting.

05 June, 2006

Volcanoes from space!

Via Bad Astronomy, here's a rather cool picture from low earth orbit of an ash plume erupting from Cleveland volcano (part of the Aleutian arc, and therefore a little bit lost).

This image was released by NASA's Earth Observatory (there's also a high-resolution shot available) and was taken by an astronaut currently on the ISS. As has been observed, this may be one of the more significant scientific contributions made by this $multibillion orbiting albino pachyderm. Yes, it is a pretty cool photo - but we have a lot of satellites out there who do this Earth observation thing full time, rather than just when they get the chance to peer out of a viewport. As an example, here's a couple of satellite images showing similar activity at Mount Merapi, in Java (which has been hitting the headlines recently). The second is a thermal image:

(images from here and here, respectively).

And, now that NASA is introducing software which allows its probes, rovers and satellites to independently direct their instruments towards interesting events (more details here), you can't even say that humans have the monopoly on choosing when to take the cool photos.