Michael Welland

Audio

Transcript

Ramona Koval: Michael Welland joins us from London. Welcome to The Book Show, Michael.

Michael Welland: Thank you for inviting me.

Ramona Koval: Congratulations on this riveting book. I must say that when I was a university student studying science I went for the biological science because things like geology seemed to lack drama, which you have completely countered with your book. So before we get to the dramatics, tell me what attracted you to the study of rocks.

Michael Welland: Gosh, that was a long, long time ago. It's one of the classics; I was a kid, family holidays, the traditional 'get in the family car and hope it continues working until you get there', and 'there' was more often than not the south coast of England, what is now of course a World Heritage site, the 'Jurassic Coast', and young Michael got interested in collecting fossils and rocks, much to my parents' delight having to lug them home. So that's what started me off as a geologist really, as a kid. My problem was that I discovered that in order to do geology I had to be reasonably good at maths and physics and chemistry and at the time they were not amongst my highest skills, so that was a bit of a learning curve.

Ramona Koval: You said there were two books involved as well, one called The Earth's Crust and one called Paddle to the Sea. Tell me about these books.

Michael Welland: Yes, it's one of those interesting things, looking back, when we learn things about ourselves so much looking back, and I came across these books again recently, and just the recollection of the thrill of opening these made me realise how important they were to me as a kid.

The first one, The Earth's Crust, was a book by a British geographer, Dudley Stamp, who was one of the leading economic geographers in the 1940s and '50s. But he produced this book that involved his collaboration with a sculptor, a sculptor who created these wonderful large-scale sculptures of the Earth's surface, of different kinds of landscapes, different land forms. And so not only did this illustrate how the Earth's surface works in three dimensions but also, for example, with a valley that had been glaciated, where the ice had scoured it out, he'd produced two models; one of what the valley looked like when the glacier was there, and the other one what it looks like today, the glacier having melted. And so suddenly it allowed me to look at landscape and look at the geology in a completely different way. And so that was hugely informative, and it was an exciting book.

The other one, Paddle to the Sea, is a classic American children's book, beautifully illustrated, that tells the story of a young Indian boy who carves a canoe with its paddler and he puts a small message on the bottom of the canoe that says 'I am Paddle, if you find me please return me to the water' and sets it off. He leaves the canoe on a snow bank which then in the spring melt, the canoe is liberated, it goes down with the melting snow to a stream, to a river, to the great lakes and eventually out to the sea. And this journey is really one of the most remarkable and beautiful journeys I think that has ever been told, and it also tells you so much about the environment that the canoe and the paddle to the sea is passing through. In many ways it's very much like the journey of a sand grain, let's face it, so there is a clear relationship here.

Ramona Koval: Of course you do talk about the journey of a sand grain, and we'll get to that in a moment. But I wanted you to tell us about this relationship between people and the poetry that they find in sand. You've seen a lot of cultural and literary references coming across that embody the idea of sand. What fascinates us about sand?

Michael Welland: I think there are any number of things. First of all, sand simply as a medium, if you like...if you find yourself sitting on the beach, more often than not you'll find yourself tracing patterns in the sand, making designs, lifting it up, letting it sift through your fingers. And indeed in the 19th century and earlier, certainly in the UK, children were taught to write using sand boxes because simply you could...it's like a blackboard but even easier, you simply write in the sand and then smooth it clean, start again. And that's the case with many examples of today's sand art is its ephemerality in that sense.

And then of course in Australia you have some wonderful examples of the Indigenous peoples of Australia having an intimate relationship with sand which, after all, is a substance which is responsible for many of your wonderful landscapes. There are many Indigenous traditions of literally telling stories in the sand. In fact some tribes have a specific name for the process of telling stories in the sand. The sand was a means of educating next generations, of telling stories of a particular tribe and so on.

And writing in the sand, using sand as a medium of communication is found all over the world, and that was one of the things that surprised me when I was researching the book, was to discover the commonalities of designs and patterns that widely different cultures around the world use in telling stories in the sand in one way or another or thought divination. Sand is a common medium for different cultures around the world to predict the future.

Ramona Koval: You've got in this book some beautiful plates of selections of sand, demonstrating the variety of sand and the beautiful differences in colours between quartz sands from Florida, and olivine from Tahiti, and some volcanic glass sand from the Galapagos Islands. And when you look at this you can see that the grains are so regular, and then you so ask this question that I had to say to myself, well, I've never asked myself this question; how come sand aggregates like this? How come these tiny little grains that are so small, how come they don't get lost in the whole big world? And the answers are quite wonderful, the idea about how grains behave when they're all together, because they do like to get together, don't they, they're gregarious.

Michael Welland: They are indeed. And of course there are so many of them, which in fact is another aspect of sand in our imagination. It is a measure of scale for us. An individual sand grain is a measure of almost the unimaginably small, we use it as a calibration of microscopic size, 'smaller than a grain of sand'. But we also use huge numbers of sand grains as representative of almost unimaginably large numbers. Carl Sagan decades ago posed the question of whether there are more stars in the universe than there are grains of sand on the Earth, and it's a meaningless question in absolute numbers, but it stirs the imagination hugely, and indeed it's a debate that still goes on on the internet today, you can just look up 'Sagan', 'stars', 'sand' and you will find all kinds of opinions as to whether there are ten-to-the 24th grains of sand on the Earth and so on. It stirs the imagination. So that's one of the reasons (to come back to your original question) that sand is so influential in sculpting the landscapes of our planet is that there is a great deal of it.

But just as importantly, as you say, is the nature of the grains themselves, and I should point out an important fact and that is that technically sand is defined purely by size, it's a range of grain sizes from a small fraction of a millimetre to a couple of millimetres. It doesn't matter what it's made of. And so you can find sands, as you say, that are made of olivine minerals, green minerals from volcanos, from quartz which is perhaps the most common sand mineral because it's one of the most common minerals on Earth. But then if you go to the tropics or indeed to the beaches of eastern Australia, many of the sand grains are made of fragments of shells, fragments of coral, they're organic, they originate biologically.

But they all fall within that same size range, and the important thing there is that that range of a granular material's size has the unique property of being perhaps the most easily transported solid material on Earth. In other words, whether sand grains are being moved by the wind or by water, waves, rivers, whatever, they are very easily picked up and carried off somewhere else. So they form an extremely active dynamic community of the Earth's natural materials.

Ramona Koval: So you're saying that they get together, they find themselves together with other like-minded, like-natured grains simply because the size of them means that they get winnowed out, in a sense, and all end up at a beach together.

Michael Welland: That's exactly right, yes.

Ramona Koval: That's very smart, isn't it.

Michael Welland: Oh yes, it's hugely tempting to anthropomorphise many of these things, that's right.

Ramona Koval: And you do actually.

Michael Welland: Yes. And then of course some of them will also spontaneously separate. If you go to the beach you will see there's the standard sand, but perhaps on ripples, perhaps in streaks you'll see darker streaks of sand. And that's the same principle as placer minerals, gold and heavy minerals, which are concentrated because they're slightly heavier than other grains of sand. And so there are all kinds of complications to the behaviours of granular communities too.

Ramona Koval: There's a lovely story about Cleopatra's beach that I want you to tell, and this is also connected with the fact that sand can be used in a forensic way. Forensic geologists can work out exactly where sand comes from.

Michael Welland: Yes, and now of course this comes back to composition as well as size. But yes, the Cleopatra's beach story is there are certain sand grains or sand size materials with the delightful names ooliths or ooids because they're sort of egg-shaped, which are formed in warm tropical or semi-tropical seas when a tiny grain of dust or a very, very small sand grain rolls around in warm tropical waters that are saturated with minerals such as calcium carbonate, and as it rolls around those minerals from the seawater accumulate around that core grain and form sand-sized egg-shaped grains. Those are called ooliths.

The story is that there is a beach in Turkey, and I've seen some sand from it and it would seem to be correct, that has a large proportion of these kinds of grains in amongst its total sand. But there are no places on the Turkish coast where these kinds of grains are being formed. Apparently Mark Antony transported these grains from the coast of Egypt where they do form and which have the characteristics of the ones now found in Turkey, he transported boatloads and boatloads of these things to this beach in Turkey in order to make it more beautiful, whiter, smoother for Cleopatra to enjoy the beach.

And this is an example...in other words, the characteristics of these grains, these ooids, told us roughly where they came from, and indeed the forensics of sand...because the nature, the composition of a family of sand grains in any one place is pretty much unique because when they move on, the composition changes, the proportions of different kinds of grains changes, they become worn away and more rounded, and because they are peculiar to a particular location, they can often have value in terms of forensic science. This started during WWII in the western United States, in fact as far east as Michigan.

There was a period when there were balloons carrying bombs which were floating across the country. Fortunately the fatalities were minimal, but clearly this was a threat, and the military geology branch of the United States Geological Survey, a branch that had just been set up, used the fact that these balloons for ballast had bags of sand which were somehow or other programmed to maintain the balloon at a given altitude for a given length of time. That sand, they determined from pre-war surveys, came from a particular beach in Japan. They then flew some aerial reconnaissance, aerial photography missions, found the facility that was making the balloons close to that beach in Japan, and bombed it. So that was the first example, although there are examples from the 19th century from Sherlock Holmes and so on, but the details of sand forensics are quite extraordinary.

Ramona Koval: One thing of course in adventure and horror movies and all of that from when I was growing up was that you really had to have the quicksand scene where somebody gets caught in the quicksand, usually the baddies, and then suddenly gets sucked into the vortex and all that's left floating on the top is some sort of hat. I was very happy to know that...I always like to know how to get out of sticky situations, and I suddenly went, hooray, I can tell now if I ever get stuck in quicksand what to do, because it doesn't happen like it does in the films, does it.

Michael Welland: No, it doesn't, although I have to say that in the Indiana Jones film, The Crystal Skull, Indiana Jones gets caught in a pool of quicksand and he does have time to give a short lecture on the physics of quicksand, and it's really quite accurate, so I was pleased with that. But no, quicksand is a situation in which the grains of sand are forced apart by the pressure of the water in between them, whether it's the result of tides and waves on a beach or water seeping in to sand from below the surface of the earth. But once disturbed the sand grains then lock in place. So with quicksand, once you put your foot in it the sand grains tend to lock around your foot.

So the problem is you are still...your density is lighter, you float in quicksand, you just don't sink in it. There was a wonderful episode of the American television program Mythbusters where they examined this as a myth, and they constructed a huge tub of quicksand and one of the presenters got into it and there's a great sequence where he's bouncing about trying to sink but can't. He's floating. But then his limbs begin to get locked in place, and that's the danger of quicksand. If you're on a beach and get stuck in quicksand at low tide and can't extricate yourself, then of course the consequences are quite dire when the tide comes in.

Ramona Koval: Because you're stuck like cement and you drown, is that what you mean?

Michael Welland: Yes.

Ramona Koval: Or you could starve to death if the tide never came in again, that's a bit unlikely, isn't it.

Michael Welland: Well, yes, but of course if you were like Indiana Jones and you were on your own in quicksand in the middle of nowhere, not on a beach, yes, you could die of exposure and starvation.

Ramona Koval: But now we can tell people this very, very handy thing, which seems to me like you're recommending wriggling.

Michael Welland: I have to give a health warning; I myself have never been stuck in quicksand, so...

Ramona Koval: This is all very well for you then.

Michael Welland: It's all very well for me, but the standard view (and the physics of quicksand supports it) is essentially no sudden movements, but if your foot is stuck in quicksand wriggle your toes so that you're beginning to get the grains which had been locked to unlock and move.

Ramona Koval: Because you're trying to invite water in to line your body, aren't you.

Michael Welland: To refill the spaces in-between the sand grains where they had locked. So yes, wriggling is recommended, and no sudden or sharp or dramatic movements.

Ramona Koval: So you sort of wriggle yourself out of it, do you, hopefully.

Michael Welland: Yes, that's the concept, as I say...

Ramona Koval: Have you ever seen it done?

Michael Welland: No, I must admit I haven't. Quicksand is relatively rare but it does occur in places on beaches. As we all know the wet sand on a beach behaves very strangely. I mean, it can be supporting your weight for some time, even though, as you might notice, wet sand, your footstep suddenly creates a dry halo of sand around your foot which is yet another extraordinary aspect to the physics of sand. But you can be walking along the beach and suddenly you find, with no apparently difference in the nature of the sand, you can find your feet sinking into it in a rather alarming fashion. It's not quicksand itself but it's still variations in the behaviour of liquid granular materials.

Ramona Koval: Tell me about this guy Ralph Bagnold, he seems like a kind of sand adventurer. Tell us about the Sphinx and his analysing of sand dunes.

Michael Welland: Ralph Bagnold (although in England it's pronounced 'Rafe' Bagnold) was an extraordinary man. He was born in the late 19th century to a family of engineers. He grew up essentially setting up as a kid his own small engineering lab so he could make things and take things apart. He fought in WWI and survived, and then in the 1920s, still in the army, he was assigned to Egypt. Shortly after arriving in Egypt he observed the first relatively successful excavation of the Sphinx from digging it out of the sand that had surrounding it for centuries.

And then while stationed in Egypt he had a fair amount of spare time on his hands and he began to explore the Egyptian desert, both the Sinai and the Western Desert. And he was intrigued by what was not known about the desert. He was also intrigued by the fact that vehicles' travel in the desert was deemed essentially impossible and he proved that it wasn't. He modified Model-T Fords in a way that they could, for a start, recirculate the cooling water system so that large water supplies weren't necessary. He figured out how to extract them from sand when they got stuck, and he drove all over the Western Desert in a number of epic expeditions, and in that process he got interested in what exactly are the processes that form sand dunes, that create the dynamics of moving sand dunes, why sand dunes are of different shapes, and why there are sand dunes in one place but not in another.

Ramona Koval: He was a good writer, wasn't he. You've got this paragraph which I'll read, and this is when he saw some dunes...is it barchan dunes?

Michael Welland: Yes, the horn-shaped, crescent-shaped dunes, yes.

Ramona Koval: He saw some of the attributes a we ascribe to organisms, and this is from Sand, Wind and War, and he says:

'Here, where there existed no animals, vegetation or rain to interfere with sand movements, the dunes seemed to behave like living things. How was it that they kept their precise shape while marching interminably downwind? How was it they insisted on repairing any damage done to their individual shapes? How, in other regions of the same desert, were they able to breed "babies" just like themselves that proceeded to run on ahead of their parents? Why did they absorb nourishment and continue to grow instead of allowing the sand to spread out evenly over the desert as finer dust grains do?'

He certainly felt the organic power of them, didn't he, those sand dunes.

Michael Welland: Yes, that's extraordinary stuff. And it's extraordinary also in the sense that Bagnold was first and foremost a military man. He went on later to form the Long Range Desert Group which wrought havoc behind enemy lines in North Africa during WWII. But he was also an extraordinary engineer, physicist, scientist in general. So he realised that those kinds of questions that he was asking in that quote had not been answered, and so he set out to set up the data gathering, the experimental approach, and really from the fundamentals, from scratch, the mathematics and physics of how sand grains move and therefore how dunes form. And his work (it was published first in the 1930s) is still referred to in modern scientific papers about sand dunes. It was very much a classic piece of work which is still of huge value today decades and decades later. An extraordinary man.

Ramona Koval: Yes, he sounds quite something. There's a marvellous description of the sound of deserts and I suppose you don't imagine that there's going to be much sound if there's no trees or rocks or anything to catch the sound. Tell us about the Aeolian activity that you find in a desert.

Michael Welland: Yes, 'Aeolian' is the geomorphologist's way of talking about things that the wind does. Aeolus was the god of the winds. Aeolian processes are ones that both carry sand in a sandstorm, on a normal day they roll sand grains across the surface, they causes the accumulation of dunes and the blowing sand also erodes rocks, erodes man-made structures and so on. And it was Bagnold that, as I say, set out the basics of physics.

But in the desert, and I've spent some time...in fact I was with one group where the expedition was retracing one of Bagnold's expeditions in the Western Desert, and it's an extraordinary place. One can see the way in which Bagnold became hooked on the desert, the environment, the processes that go on there, because there is no vegetation and so when the wind blows there's no sound of the wind blowing through the trees but there is the sound of wind somehow or other intersecting with the landscape, and when it's sand there is literally, in a good wind or in a sand storm, there is the sound of moving sand, that sort of rustling background sound. And you become conscious of these things simply because there is no other sound, the wind is the sound of the desert.

Ramona Koval: We've got a beach near Melbourne here that we call Squeaky Beach and when you walk along that you can actually hear each footstep. What's that about?

Michael Welland: That's part of a large-scale phenomenon that has been noticed for centuries. Marco Polo first noticed the sounds that sand can make when he was crossing the Gobi Desert and talked about it. And Bagnold noticed this too, that no only do you sometimes get beaches where the sand grains squeak but that some sand dunes will spontaneously boom or sing, they will emit often low frequency sounds, notes, musical notes, sounding rather like a didgeridoo, I have to say. On the rare occasions that I've been lucky enough to hear a sand dune emit a sound, it's a booming didgeridoo-like sound.

But different sand dunes around the world consistently apparently emit the same note, an F-sharp or a C or whatever, and it's a huge debate amongst the Aeolian process scientists as to exactly what causes this. We know that it's to do with avalanching. You can often stimulate the booming sounds by simply hurtling down the steep face of a sand dune, and with every step you can start hearing these booming noises which often tend to gather in volume. So it's to do with the avalanching and moving sand. But there's still a considerable debate as to whether the sound is generated simply within that surface layer of moving sand or whether the structure of the dune has a whole acts as a kind of amplifier. Various researchers get quite excited about the differences between these hypotheses. It's just a wonderful natural mystery.

Ramona Koval: Somebody must have recorded the sounds and put it together in some kind of new music, don't you think?

Michael Welland: The sounds are certainly recorded, yes, and I had the idea...in fact it was for a BBC program over here called The Museum of Curiosity and you're supposed to come up with something exotic to enter into this imaginary museum, and I had the vision of creating a choir of sand dunes in this museum. You'd select each sand dune according to the note of the music scale that it emitted, you put them all together, and as they migrated around the museum they would emit their notes, which would of course be random. But ultimately in the same way that the large number of monkeys and typewriters would create Hamlet eventually, eventually these sand dunes would spontaneously get together and play the theme tune from Gone with the Wind or Lawrence of Arabia or something like that. It's a nice idea.

Ramona Koval: It's a great idea. But this idea of sand dunes moving, it's not so great if they're moving towards your city. What's going on with Beijing?

Michael Welland: Beijing has got both dust problems and for the immediate future the dust storms are certainly the greater problem and they were a potential problem during the Olympics, simply that desertification, that is very often through agriculture and through the over-cultivation, the overuse of the soil, the soil degrades into dust, the dust is picked up inevitably by the wind. And so that has been a major problem in large parts of China, and the resulting dust storms are very dramatic. But along with the dust comes sand, and once the wind gets hold of the sand it creates sand dunes. There are now sand dunes within a few tens of kilometres of Beijing which weren't there before. They're apparently a great tourist attraction. But there is a gathering herd of sand dunes that in the course of a few years (because these things move at a metre or several metres a year) will start threatening the human infrastructure of the city.

Ramona Koval: It's sort of like King Cnut.

Michael Welland: Yes, indeed, King Cnut, who of course contrary to the popular interpretation was actually demonstrating his inability...

Ramona Koval: That he couldn't.

Michael Welland: Yes, quite.

Ramona Koval: As listeners can hear there are many marvellous things in this book and we haven't even scratched the surface, as it were. The book is called Sand: A Journey through Science and the Imagination and it's published by Oxford University Press. Michael Welland, thank you so much for being on The Book Show today.

Michael Welland: Thank you so much for inviting me, I really enjoyed it.

Publications

Title: Sand: A Journey through Science and the Imagination

Author: Michael Welland

Publisher: Oxford University Press