The experimentalist

I got asked a question the other day, and it got me thinking. The question was ‘what makes a good scientist?’

The more I thought about it, the more I realised that while there are a number of key traits that I considered central (‘lateral thinking’, ‘good communication skills’, ‘self motivated’), I could think of well regarded professional researchers who were exceptions to each of them. The only skill I have been able to settle on so far as being universal is the ability to critically think.

There are scientists who are team players, and those who are better working alone (for their own, but often also their colleagues sanity). There are plenty of careful scientists with a precise and measured approach to everything. There are also many I’ve come across who are often a little more slap-dash and clumsy, but who churn out excellent science nonetheless.

I also don’t think research scientists are more intelligent than the general population. We’ve been trained to look at problems and think in a certain way, and we draw on a lot of experience and education, but given those factors I think most people could do what we do.  There’s nothing in our skillset and abilities that can’t be taught.

It was then I realised what the other common factor is to every professional science researcher I know. A love of the science.

Pay and conditions for researchers aren’t that great. While you’re still in school, the people who started work at 16 will have 10 years of earning and promotion behind them, while you’ve been racking up debt. The PhD process is well known as a tough slog, and you then begin hearing rumours that there are far more PhDs being produced than there are available jobs. If you get lucky you then start a career at a moderate level of renumeration, but requiring years in short term contracts which often mean migrating nationally or internationally.

Despite all that, most postdocs I know love their jobs. Sure, they get pissed off at the moving and instability and the general climate of work, but they still love their jobs because they love doing the science.

There are plenty of people who get their PhDs and have the love of science beaten out of them by the time they finish. Or at least that love is overwhelmed by other needs or desires. And there seems to be a reasonable amount of work available for those people. In fact, these other jobs also tend to get paid a hell of a lot more than those in research. Which again highlights that those who stay in it are generally there for the love of carrying out cutting edge science.

In my quest to give a more comprehensive answer to the question I’d been posed I decided to try and concentrate more specifically on my own type of work – that of experimental science.

Here it is more specifically important to maintain a methodical approach. But I find an almost playful inquisitiveness is also really important.  Just this afternoon I was having a conversation with a colleague about the benefits of spending some time just messing around with the equipment and materials you have available to see what interesting behaviours and features can be encountered. In fact, an interesting point came up when my colleague explained that next week he is going to be letting some Masters students loose on trying to model debris flows. He made the excellent point that quite often what they do is crazy and illogical, as they do not have the base of experience to know what *should* happen. But we also agreed this can be a fantastic boon, as they have none of the preconceived notions of how a particular method should be carried out. So while there can be a lot of ‘failed’ experiments, and they learn a lot of lessons about why certain things are done certain ways, both of us fully intend to go and see what they attempt and see if we can’t learn a few things ourselves about what features and flow processes might be investigated with a little bit of a leftfield and original method.

So what traits are essential to your field?

I’ll leave you with a video I put together today showing what happens when you pass gas through a powder material at such a high rate that the material passes through ‘fluidised’ and comes out the other side as bubbling. Stress chains within the material allow conduits to form. I’ve seen it described in many papers, but it’s the first time I’ve played with the mechanism myself, and took the opportunity to use the high speed camera to record it. I think it’s pretty neat – you can see the discrete gas bubbles pass up the sidewall. It was shot at 1000 fps and plays back at about 1/15 speed (30 seconds of video is 2 seconds of footage – timestamp is in the top right). There’s a 2cm grid on the right for scale. For some reason I can’t link to the HD version, so make sure you select the HD option on playback.

Posted in Experimental, General, Geology, Physics, Science, Sedimentology, Volcanism | Tagged , , , , , | Leave a comment

Measure twice, cut once.

My dad was a design and technology teacher. I was exposed to the arts of woodwork, construction, design and so on as a child, and – while my brother went off and became an engineer – I have to say I’ve not particularly made use of those skills since I was doing my GCSEs. That said, I always enjoyed technical drawing, the precision and 3D spatial planning (and indeed, that same 3D spatial awareness that is so important in many aspects of geology).

While I was doing my PhD and had to design some flume equipment I had a flash of interaction with things again, but it was an absurdly simple three-part flume that a 7 year old could have designed and assembled.  For this current project, however, somewhat more time and effort has had to go into flume design. In fact, the full first month was spent doing little but designing and refining the flume, to ensure it was capable of producing the results I want to achieve without being blown apart by high pressure gases or collapsing under its own weight.

So I found myself with a ruler and protractor drafting out isometric sketches and trying to make sure everything fitted together. Then a stroke of genius hit and I booted up Google Sketchup. I’d used it a few times before, but I reasoned that while I could sketch by hand as much as I wanted, by producing a 3D model I would ensure that all the separate parts would fit nicely, and I could read the numbers for part ordering straight out of the model.

Sketchup models of some flume parts.

And I was right – in fact, it was even quicker than drafting by hand. A couple of people in the lab were quite impressed by these models I was producing and got interested.  I took images of the models down to our outstanding workshop engineer, and he was very pleased with the detail – illustrations of where cutouts needed to be made, clear ideas of where we would need PVC, where we would need aluminium, where perspex, and even where particular joins should be made (and how).  It enabled me to design the somewhat complicated hopper shape (do a Google search for ‘hopper geometry’ and you’ll quickly realise that simply whacking a great big box on top of a release mechanism is not the done thing), and was even able to ensure it would be of a certain volume and mass.

So I was ever so pleased with myself when the purchase order went off with all the outputted measurements for the 75 or so separately cut pieces of material, in a variety of materials and thicknesses.

I was less pleased this morning after an hour in the workshops ensuring that all the pieces fitted together nicely to discover that the 3000 mm x 100 mm x 10 mm  perspex flume base had been delivered at 3000 mm x 130 mm x 10 mm. Sounds trivial, but Perspex is really horrible to cut, even in a well equipped workshop. A 3 m length of it is unwieldy and impossible to deal with without some very specialist equipment.

I checked the purchase order. 3000 x 130 x 10. Bugger. How did they make that mistake. Why did I not notice it? I spent some time cursing myself for not checking the purchase order more carefully. I went and double checked again. Then I went and looked at the original paperwork. The spreadsheet I had specced everything on was correct. Then I checked the order email. I’d sent.  Hmm. That was wrong.

So, what had gone wrong? Idiot cut and pasting. I had copied the details from one part, and pasted them, then pasted the same values for the next part on the list.

In summary, after a morning of ferrying a 3m length of perspex to and fro between the suppliers and their enormous cutting machine to remove 30 mm of excess plastic, I propose a 21st century modification to the age-old adage ‘Measure twice, cut once’:

“Measure twice, cut once, paste once, check”.

At least it was cut too big rather than too small – that would have been both annoying and expensive.

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Tongariro Fireworks

Following the little spike of activity back in August, Tongariro in New Zealand reactivated today with a 5 minute explosive eruption jetting up a small plume and generating some very limited pyroclastic flows. With it being a daytime eruption, and with New Zealand getting firmly into its summer season there were, inevitably, a number of people attempting the Tongariro Crossing – a very popular hike that snakes past the dramatic Mt Ngaruhoe and up onto the nested craters of Tongariro proper.

Among this group of walkers was a pro film crew.  The net result is that some truly spectacular video got captured of the plume immediately after eruption, and showing some of the small PDCs generated from it. I strongly recommend going to have a look here. Not only do you get the joys of some lovely volcanology, but the added bonus of a soundtrack of overexcited and dramatically screaming children.

The volcano is at Alert Level 2 and Aviation Colour Code Orange.

EDIT: Here’s the seismics from Geonet for the last 24 hours. You can see the observed eruption a little before the 10 hour line (the drums are marked in hours before present, with present being about midnight New Zealand time, and the eruption going off at about 1.30 pm local time).  It looks like there’s possibly been a further pulse of activity just over 2 hours ago.

EDIT 2: Quick and dirty compilation of the webcam images from Geonet / GNS Science, showing a lot of geothermal outgassing activity before and after the eruption. Available on YouTube here.

I’ll update as and when I get a bit more info.

Posted in Education, Geology, Hazard Assessment, News, Science, Volcanism | Tagged , , , , , , , , , | 1 Comment

Accretionary Wedge #52

Been a while since I had a chance to get in on the Accretionary Wedge, which – for those of you who are perhaps not familiar – is something of a geoscience blog carnival. Once a month, someone hosts a new topic for the rest of us geobloggers to wax lyrical about.  This month Vi-Carius is hosting, with a topic broadly about ‘geoscience courses you wish existed’

Now, it’s been a while since I was an undergraduate. In fact, I was away from geoscience for several years before coming back to do my PhD.  And that’s really where my dream course would have fitted in.

Rather than Geoscience 101, I’m thinking more a ‘Geoscience 999′. A short sharp kick-up-the-rocks for people who could do with a refresher. Maybe 5 or 6 hours of lectures, one each recapping the key details (and last 10 years developments in) each of half a dozen key subject (plate tectonics, palaeo, geochem, geophys, sedimetology and volcanology?). Broad strokes coverage, with updates of key concepts where necessary, each followed by 3-4 hours practical work getting back up to speed with stuff like microscopy, map drawing, strat logging, etc. That would really have made my life easier.

That said, I can understand that actually it’s only marginally useful for a lot of people. So that gets me wondering what would be most useful for the most people. And by most people, I’m extending the remit slightly to mean everyone. Not just geologists. Not even just university students. The whole bloody lot of you. The answer I have come to is informed by the experience I’ve had teaching, lecturing and demonstrating, and remembering one of the most useful lectures I’ve ever had.

That lecture was given by Dave Waltham – who ended up as my future PhD and eventual postdoc supervisor. His qualifications are in Physics, but he has diligently spent most of his career at the Earth Sciences department at Royal Holloway  University of London ensuring – among many other things – that there was a friendly face and a clear explanation awaiting any geologist who was at a mathematical or conceptual roadblock.

And the lecture was this: Ballparking. At its simplest, how to calculate a rough first-order approximation for any given calculation.  As professional researchers I think it is something that we get good at doing, and the ability to quickly estimate whether something is ‘about right’ or not is phenomenally useful in a vast array of situations. Eyeballing a recipe when you’ve only got 2 eggs instead of 3? Ballpark it. Trying to calculate how to split a restaurant bill? Ballpark it. Trying to work out how many cricket balls you can fit in a stadium?…. You get the idea.

The interesting thing is that it is a skill that I certainly find is absolutely lacking in many people. Knowing how to simplify what would otherwise be a complex calculation into a first-order accurate approximation you can do in your head – or at least in 20 seconds on the back of an envelope – is something that everyone would benefit from. Imagine the time that could be saved!  Everything from working out whether a cheap but high mpg car is better value than expensive low mpg one, to arguing about how many whales you could fit in the oceans.

Ballparking is not necessarily an intuitive skill, and there’s plenty of shortcuts and tricks that a taught course should pass on. When you can and can’t round numbers, and by how much, what are reasonable simplifications, and which are not. Giving everybody the confidence to look at a number presented to them in context and the ability to judge whether the data are good would – I think – be a huge boon to society.

So that’s my wish. Quick and dirty maths for the masses.

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The insanity of the Italian legal system

Well, it’s official.

The Italian courts have found half a dozen scientists and a government official guilty of manslaughter over the failure to accurately predict the risks of the 2009 L’Aquila earthquake which killed 309 people.

This has been rumbling along for years now, indeed here’s a previous blog post where I outlined the case in more detail.

I am actually stunned by the utterly ridiculous conclusions of this hearing, let alone the fact these men now have 6 years in prison to look forward to for failing to predict the unpredictable.  Presumably we can shortly expect a series of high profile cases of bookmakers taking their employees to court for gross negligence for inaccurately determining the outcome of future sporting events.

I jest.

The implications of this finding however, are more worrisome. Given this outcome, who could blame Italian seismologists for being reluctant in the future for getting involved in the forecasting business at all.  Public service science in Italy may have been irrevocably damaged by this judgement, and it’s going to be a while before we know how badly. The only winners in this case are the lawyers who have no doubt earnt a pretty penny in the 3 years this case has now been building for.

Shame on you, Italy.

Posted in Earthquakes, Geology, Geophysics, Hazard Assessment, Media & Perception, Not even wrong, Science | Tagged , , , , , , , , | 1 Comment

Scaling new horizons

Mayon, Phillipines, 1984. Gravity currents, in the form of pyroclastic flows, propagate down the flanks of the volcano. From http://en.wikipedia.org/wiki/Pyroclastic_flow

It’s fair to say that when most people ask what I do, I simply reply “volcanologist”, “sedimentologist”, or “geologist”, depending on the audience. On the infrequent occasions they ask further what I do, it usually gets summed up as “I see how well things go downhill”, or “I study how different flows behave”. I might even go into detail about the hazard mitigation or petroleum reservoir potential of some of these studies.

The fact is though, that on the whole, I try to keep it absurdly simple.  And, on the whole, that serves the needs of the casual question, and lets us get on with the business in hand (which, to be fair, is quite often “having a beer”).

However,  since I discovered I was moving to France for this new postdoc I have found a more insistent repetition of “what is it you’re actually going to do?” The temptation is often to pull a Barney Stinson

But, apparently I don’t wear enough suits to get away with it. So, here we go. I’ll be spending my time running scaled models of gravity currents. The interesting thing is that everyone seems to ask about the ‘gravity current’ bit, and just take the ‘scaled’ part for granted. However, the ‘gravity current’ is actually in many ways the dull and straightforward bit – very simply, dense stuff goes down hill. You put dense fluid at the top of a slope, and gravity moves it down that slope. I just record the flows and measure the deposits.

Far more important is the ‘scaled’ part of this little world of sedimentological wonder. It is easy enough to imagine that building a small model of a volcano and pouring stuff over it might produce realistic results. However, the fact is that this is very far from the truth. While it seems obvious that you can model the behaviour of large particles in a big flow by using smaller particles in a smaller flow, there is a question firstly of ‘how big do the new particles have to be’.  But there is also a question of ‘what happens with things like gravity?’.  No matter how big or small I make the flow, gravity is a constant I can do little about.

And that’s not all. Things like particle friction, and fluid viscosity also don’t change (or change in non-linear ways). So now, if you change the volume of the flow, you’re not actually changing all the parameters at the same time.  As you might imagine, this means a flow at one scale can behave completely differently to a flow of identical materials and relative height and width at another scale.

Then you get all sorts of other interesting little problems creeping up. For example, when you work with sand-sized particles, there’s a number of weird sorting mechanisms that occur. If you try and use even finer particles, you start getting cohesion – where everything from humidity to van-der-Waals forces starts to stick particles together.

In short, scaling is probably one of the biggest challenges in any kind of geophysical modelling. The scaling problems become less pronounced as you make your models bigger and bigger, but cost and practicality then become your adversaries.

There’s a number of solutions (or at least workarounds) when you’re looking at scaling of experiments, and it comes down to trying to describe the various parameters of the flow using dimensionless quantities. As the simplest example, I can look at the aspect ratio of a flow (how long it is, divided by how tall it is). Because both are measured in meters, the aspect ratio is a simple number with no dimension. Hopefully, the aspect ratio of the flows in the model would be the same as the aspect ratio of the flows in real life. And we do that for everything from particle densities, to pore-pressure and fluid viscosities.

It’s worth noting that you will almost never achieve a perfectly scaled model. But, with care, you can get close. In the words of George Box: “All models are wrong, but some are useful.”

So what do I do?

Well, for the first month of this particular project, I’ve been spending a lot of time doing the calculations and designing the equipment to ensure that the experiments I’m going to be running can actually inform us about flows which – rather than being a few meters long and centimeters high, are kilometers in length, and tens of meters high.

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The end of the hiatus

I know, I know.

In my defense, the last months have been insanely busy. There was the usual dip in activity as the summer arrived and I was able to focus on some research problems. Then, as summer got going, I discovered that the postdoc fellowship at the Laboratoire Magmas et Volcans in France was going to happen, and from that point onward finding time to dedicate to this became somewhat secondary to the numerous other things which needed my attention.  With the turbidity modelling postdoc finishing at the end of September, and the France postdoc starting three days later, it is really only now – 12 days after my arrival  - that I’ve got myself sufficiently settled and arranged that I can begin getting back to a regular schedule.

So, my apologies for absence, and an assurance that normal service is now resuming.

I’m thoroughly enjoying the new work – although at the moment it’s focussing a lot on getting back up to speed with the literature related to fluidised gas-particle currents, and designing the flume apparatus that I’ll be using over the next 12 months.  Oh, and getting my French slightly above the abysmal pit in which it currently resides.

C’est la vie.

See, it’s coming along already.

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