Meandering acrosss the digital divide III: Pedagogy of a meandering stream

My teaching was clearly rooted on the other side of the digital divide from here and now. In it I developed a fairly consistent program for using meandering streams as a means of teaching how geology goes about answering its basic question (how did the Earth get to be the way it is?) by bringing to bear the non-historical sciences, in this case physics.

I started with an in-class problem. The students got a piece of paper with a meander loop drawn on it, and a data set with depth and water velocity. As I recall now I stole the data from something of Strahler’s. Actual stream gauge measurements. That required some explanation of measurement and operationalism. The students plotted the depth profile and the velocity profile across the meander loop. Needless to say, there was a close correlation: deeper water on the outside of the curve, running faster where deeper. Generalizing from this, I showed them how to draw the thalweg down the length of the stream shown on the map, completing the three-dimensional view of the  inter-relationship of process and form.
The next step was to, hypothetically, dump a load of mixed size sediment into the river at the thalweg on the cross-section and follow it downstream, using the stream competency diagram (particle size vs stream velocity). I had to resort to drawing my own version, even if there was one in the text. With it by interpolating velocity at max at the thalweg to zero at the bank, the students could figure out where to look for the sediment: on the next point bar downstream on the same side of the thalweg it started from and sorted out by size.
In the interests of saving time during the term, I dropped the in-class problem aspect and just lectured my way through these ideas. That doesn’t work nearly as well, but I needed to save the time for my other problems that I thought were more fundamental to geology- eight in all. The mysteries of log-scaled graphs, interpolation, and diagrams that show process but are too easily conflated with form just took too long to unravel.

After I felt that I had the students mind thoroughly into the stream, I went back to the cross-section and started talking about the actual point to point velocity and how that could be measured. I re-introduced the turbulence, showing where it maxed out on the outer part of the curve, below the surface, not at the bottom, sometimes with some helical flow. Then, with the bald assertion that the velocity plotted in the competency diagram was a surrogate measurement for the degree of turbulence, which we did not know how to measure, I further asserted-teachers in a classroom can get away with crap like that!-that if the stream was eroding, the point at which the erosion occurred was where the turbulence was maximum where, in turn, velocity changed the most in the shortest distance. That is, below the water surface, on the outside of the  curve, not at the bottom. Sediment removed from that point would leave the unconsolidated material above it un-supported, and it would collapse into the stream. All this stuff would be carried downstream to the next loop and depositied on the point bar, sorted out according to size. Frequently there were students who had swum in rivers, knew where the beach was and where the swimming hole was, and could testify about walking into the water over increasingly coarse sand, pebbles, etc.

The net result of these processes operating was the migration of the asymmetric profile sideways, leading to the side-cutting action of the stream and the accentuation of the meander loop, etc. By introducing some speed-up and slow-down of velocity around the loop, down-valley migration can be accounted for. Oxbow lakes, clay plugs resisting erosion(back to the competency diagram): it fits together beautifully. Occasionally you can see the click on the face of the student when all the various pieces of the puzzle fall into place.

All of this leads easily to saying that once the form of a meander is established, the process that occupies the form will re-create the form continually. The only remaining question was what caused the stream to wiggle in the first place.
I then went through the familiar examples from Leopold’s work of melt water streams on glaciers, the Gulf Stream, the jet stream in the atmosphere, even adding my own favorite examples, streams flowing across beaches, like at Alamere Falls. I could say at that point that meandering seemed to be an inherent property of fluids in turbulent flow, so we have to await a further understanding of turbulent flow from the people who are responsible for that sort of thing, the physicists.

Uncomfortably, the above development implies that all streams should meander. So that required some work on the conditions that rule in non-meandering streams: braided streams (variability of sediment load and discharge) and riffle and pool streams in canyons (flowing water can’t cut sideways into bedrock- the cutting tools are all in the bottom. They are doing the best they can.).

Meanwhile, geologically speaking we could say that the observational evidence indicates that we need refer to nothing beyond the current on-going process to explain the existing form. The independent variables in a stream system are the discharge and sediment load, which are both determined basically by climate. The internal dynamics of the process adjust the form to meet the needs of uniform dissipation of energy. While the process can approximate balance or equilibrium or steady state at the local time scale, so long as there is land above water, the planet Earth is not gravitationally in a stable configuration, and will continue to change at the global time scale. The internal energy residual and generated within the Earth is now, and has for nearly 5 billion years, acted to counter the force of gravity, fueling the continuing and shifting interactions at the surface of the Earth that we call geologic history.

Having spent the last four decades in front of a classroom, dealing with the structured ignorance of the students, I am a little intimidated by the staggering amount of new knowledge the scientific community has compiled while my back was turned, facing away from learning and toward teaching. To be a little more precise, I have been learning, but the thing I have been learning about is hidden behind that phrase “the structured ignorance of the students” and how that clashes with the fundamentals of science. In this process, I have been forced to re-learn those fundamentals again, but trying now to look at them from the point of view of someone who is, consciously or unconsciously, committed to a radically different frame of reference. But that’s not this story!

The last Alamere: no beach, no stream

Meandering across the digital divide II

In his book The Step to Man, John Rader Platt predicted in 1966 that the time would come when there would be enough computer memory available that every thing that had ever been written could be stored digitally for our retrieval. As I recall he also posed the question that the technology evokes: what to keep and what not to.

We are close to being there and certainly are dealing with the question. I ran into it while trying to locate a favorite article of mine: Bela Julesz: Cooperative Phenomena if Binocular Depth Perception (American Scientist Vol 62 No 1 Jan-Feb 1974). I knew I had it on my bookshelf, but I couldn’t remember the date or the author’s name. All I had was the notion that I could remember the cover picture, if I saw it. Turns out I did. It’s a sea turtle. But rather than committing myself to searching through all my back issues, I thought I would let google take a stab at it. So I put in “random dot stereograms” and came back with Julesz name. I went to the American Scientist website and put in Bela Julesz, and got NOTHING!! Now that is a crime, and a lesson of some sort. So I started leafing through the back issues on my shelf, searching now for Julesz on the content page. Got it!

The thing about this article is that it reproduced an almost full page random dot stereogram, paired red and green dots arranged by computer in stereopairs on an arbitrary geometric surface, accompanied by red and green lensed filter. You hold these filters over your eyes and wait while the brain begins processing the data. Minutes go by, while this goes on. Slowly, the form begins to emerge. Finally, you see the whole form. You can almost hear the two sides of your brain chattering away about which red dot goes with which green dot to produce a coherent form. It is a very convincing experience that says you see the world as a constructed image.
I have re-checked the image and my eyes can still construct the form relatively quickly, though not immediately after several years-since the last time I did this.

But the article was not reachable by searching the Sigma Xi/American Scientist site. At AAAS you can access John Platt’s  piece on Strong Inference, and T C Chamberlain’s Multiple Working Hypothesis classic. You can read Leonardo’s handwritten notebook. So it’s easy to think that you have available a world of literature. And it’s easy to get to.

But.

Unless someone who has a budget to cover it, and the sense to recognize its meaning, material produced prior to the digital revolution can be left un-scanned on the shelves, somewhere in the stacks. But who has un-prioritized time to meander through the stacks  just looking at  not looking for? Well, retired old men, but who else.

Compounding the situation in geology  is the coincidence of the digital divide with the conceptual divide generated by the avulsion-I just learned this word, as it applies to meandering rivers making major changes in  course- from Geosynclines to Plate Tectonics.  It is easy for the younger generation to feel that there is nothing meaningful to look for back in the stacks.

That makes it easy, in turn,  for a person from the older generation to complain about the contradiction of students of a historical science ignoring the history of their own science. Fortunately, science types learn that doing hard but meaningful things can be a lot of fun!

Here is another photo of Alamere Falls. The stream here is running straight down the steepest slope, fulfilling the common expectation.

Alamere Falls, February 2005 from http://www.bahiker.com

Meandering across the digital divide I

Earlier this month, I made a comment on Highly Allocthonous and followed up by posting here the scanned photos below. Subsequently, I removed the photos and am now returning to the project.

As is usual for me, I am writing from a title, not knowing exactly where it’s going, but with some confidence that it is going somewhere. Meandering, in a way. But then the sinuous movement of flowing fluids themselves are the consequence of not of complete disorder nor of a form imposed on it externally, but rather seem to be an expression of some aspect of turbulent flow. Turbulent flow, of course, is in the domain of physics, somewhat to their chagrin. I have been happy to leave the subject there in my teaching of introductory geology.

The digital divide is not so simple either. I have encountered it within the faculty of my college, certainly within the classroom, in my doctor’s office, anytime one does some kind of literature search. I wondered when I made the comment if the image that I was familiar with was, in fact, across the divide from the author of the post, who gives every impression of being diligent, competent and energetic in her pursuit of science. From the response, I tentatively conclude that was indeed the case.

The digital divide is multidimensional, and I will do some more meandering around it. Perhaps there is a basin along it somewhere. I didn’t know that there is a basin in the Continental Divide until I was driving through Wyoming on day. Singing a Sara Carter song, actually.

“Go a-railroading on the Great Divide

Nothin’ around me but Rockies and sky..”

For now I will leave you with a favorite photo of a meandering stream from a 1979 Sierra Club calendar (by Steve Manning).

Alamere Falls, Pt. Reyes, California.

 

 

Words and numbers: Aristotle and Ifrah

I have been playing with some time-lines, working on a 11×17 sheet that ranged through the last 10,000 years. It occurred to me to show on this graph the time periods covered by some books I have been reading lately. That is, to show the range of time that each book covered. My immediate reading was  The Trial of Socrates: I F Stone, but the first book I lined out on the graph was The Horse, the Wheel and Language: David Anthony. Then I tried to put on one of my favorites,  The Universal History of Numbers: Georges Ifrah, but it turns out that people have been symbolizing numbers a lot longer than we have been symbolizing word-sounds, so that I could not put them on the same graph.

The first recorded numbers were notches on sticks. The first written numbers were quite possibly words, rather than number symbols, which, in turn were quite possibly also the first words. Since that time, words and numbers have drifted apart into their own academic departments. Too bad!

According to Ifrah, the Brahmins who shepherded the number system that became ours across the threshold from oral to literate cultures asserted that the numbers had no history. They were simply given to the Brahmins by the gods. Plato said much the same thing about the spoken language as he and the other Greeks accomplished the same task for the spoken language.

We can follow the history of numbers through the mysteries of e, i, pi, 0 and -1. But what about the history of language development? By the time 2400 years ago when Aristotle recorded the rules of grammar, logic and rhetoric, the spoken language had been evolving for perhaps 800,000 years. Most of us ordinary people are still laboring to catch up with Aristotle.

Only in the time since then we have been able to look at written math symbols, apply logic to their manipulation, invent algorithms and equations like Euler’s.

Before venturing into some philosophical exploration of the meaning of all that one should recognize that natural selection did not produce these linguistic goodies for the sake of philosophy. Rather, there was some practical problem that they resolved in some way. And the resolution of practical problems only has to reach the standard of practicality. They don’t have to be “The Truth”.

High school earth science: Is it a good thing??

I have been “away” for the last few months coping with a birthday (77) and a diagnosis of Parkinson’s disease.  I ran into a piece at Oakland Geology on the subject of earth science courses in high school, particularly Prof Eldridge Moores efforts. That bounced me into writing the current post.

From the Preface: Physical Geology; Longwell, Flint and Sanders (1969) John Wiley.
“We believe the text will be readily comprehensible by students with no more than secondary-school background in physics, chemistry and mathematics.”

In 1969, secondary-school earth science courses were rare to non-existent. But the movement was on, rationalized in many ways, including the currrent ones. I was involved in this period with an NSF project at San Diego State College in training high school teachers in geology.

Then the Law of Unintended Consequences reared its ugly head. We all thought of earth science as being an enrichment of the high school curriculum. But it became a substitution, and that during a time when high school curricula were becoming generally impoverished, particularly in science. My own graduation from a basically average public high school in 1950 required four years of science in the academic track. But that has subsequenty been cut in half.

Thirty years later, when I surveyed my community college students in Physical Geology, nearly half had taken only an earth science course in the physical science category. Another 40% had taken chemistry, 10% had taken physics and all of those had also had chemistry. The remaining  group had nothing at all to report. Perhaps that was in part sampling error or simply due to the fact that a high school diploma is not required for community college entrance in California.

The consequences were as you would reasonably expect. The students who had only earth science were the least well prepared for a college level geology course.

Of course! The students were in my geology course, not in a physics course or a chemistry course, even though these courses also fulfilled the degree requirements. The “average student” avoids math based courses, in high school and in college, and arrives in the geology course with the expectation that nothing particularly challenging is ahead of them. There was occasional outrage at even the necessary reference atoms or elements or equations for gravity or seismic velocity. The students who had no background were at least aware that they were in for some work.

But the “average student” that graduates from a California high school does NOT end up taking Physical Geology at a prestigious University. The entrance requirements screen out “average students”. The aspiring elite students know that to get in to their first choice schools, they have to show high grades in hard courses, so they very well may meet the requirements stated above by Longwell, et alli., wherever they ended up (sometimes in my classes for personal reasons).

I urge you to take these circumstances into account. I am heated about the subject because my own career path took me from average grades in the average high school through a community college to the prestigious University. It is a well travelled path; a high percentage of university graduates follow it- perhaps half. Requirements are coercive. The aspiring elite student is already coerced by aspiration itself. Coercing the less aspiring into learning skills that open up posssibilities is not a bad thing. And in science, chemistry and physics are basic skill courses!

The unintended consequences of adding earth science to the high school curriculum has been the subtraction of basic science skill courses from their study lists by many students, to their ultimate detriment. In the long run, it hurts students and is counter-productive to enlarging the geological perspective that we so desperately need to cope with the problems the world community now faces.

Virtuality

Somewhere along the time-line of the Earth, extending from 4.7 billion years ago until now, everything you know about, care about, like or dislike, love or hate or are indifferent about came into existence. Nothingness may have existed somewhere forever, but no thing on the Earth that is present now in some form existed in that form at the formation of the planet. Every earthy thing came into its earthy form somewhere along that line. When you become convinced of the correctness of this proposition, a great many question spring up in any discussion or debate. When did the IT that you are debating begin? From whence did it come? What were its precursors in the time before? What were the causes, contingencies and coincidences of its formation?

At a New Year’s/birthday party, the assertion came out: “Virtuality was born in 1948, with the advent of television.”

While it is clear that “virtuality”, as an earthy thing, had to come into existence from its predecessors at some time, I think AD 1948 is way too late. It has erupted into the forum of debates at parties only much more recently, to be sure. But that is because it has only drawn attention to itself after being exponentially magnified by the digital revolution.  Before the digital revolution, virtuality was constrained, living only in the pages of novels, the scripts of plays, the exhortations of poets. In this guise it was frequently mistaken for “truth”, that is, something better than the imperfect grit of the world as it actually exists.

But it has been around here in that earlier form for a long time. And even before the printed page and literacy began molding the human mind, there was the oral world of myth and magic doing the same job in a simpler way. Pavlov’s dog showed the way. By the simple association of the sound of a bell with the presentation of food, Pavlov could prompt the dog to salivate simply at the sound of the bell- a virtual presentation of virtual food. Of course, he also found out that you couldn’t fool even the old dogs indefinitely.

The first practitioners of virtuality manipulation were the storytellers using the controlled bells of their voices to invoke the spirits around the campfires of our ancestors. That is also where we all start our journey through virtuality toward actuality, believing in the “truth” of the stories we are told. But from time to time, things fall apart- there’s a novel for you! Perhaps we are living in a Hegelian dialectical moment, when virtuality taken to extremes will succumb to its antithesis.

History of Civilization: a summary for the 21st Century

History begins, according to scholarly historians, with the written record. This statement is, in itself, evidence of the first phase of the history of civilization, the establishment of the hegemony of the written word. That is, it is an example of the expression of the primal power struggle that is characteristic of human societies, amongst others. In this case, the power struggle was between an established power elite whose power was based on oral skills and an aspiring elite-Plato and his group- whose skills were developing with the then new technology of writing.

The first major phase of our history involved just exactly that: the overthrow of the older, oral based culture with the newer written based culture. The rise the monotheistic “religions of the Book” were an integral part of the struggle.

But the very success of the enterprise generated problems, for the establishment of “the Book” raises directly the question of “Which Book?” The answer to that question was, obviously, “Our Book!” The struggles to establish one Book have followed down to the present time in what can be called the second phase of our history. That struggle was to establish the hegemony of a particular Book over all others. I call this the struggle to establish the hegemony of a monolithic orthodoxy. This is the struggle that dominated the 20th Century, and still goes on.

But the struggle is in vain, for the world view that any orthodoxy displays is but a virtual world created in the mind by the flow of words. The words may map the terrain of reality with great effect for solving particular problems, but those maps are not the reality that actually exists! There is always some aspect of the existence that escapes or is ignored by the word-makers, and ultimately that reality will dismantle the theory the orthodoxy is based on.

What to do?

One cannot give up and go back.  The asymmetry of time forbids that.

One can go forward, understanding that orthodoxies are but special cases of a more general phenomena- plagiodoxy. Further, that multiple plagiodoxies give better perspectives on existence than any one of them. We may not be able to solve the problems we are faced with, which the sales pitch of the orthodoxies claim to do. But we will stand a better chance with a clearer image of the problems themselves.

Eclectic Plagiodoxy- the map metaphor

From Martin Rudwick:

The Great Devonian Controversy:  The University of Chicago Press (1985)
P 454    “Bookish people with no practical experience of mapping often assume that a map is an unproblematic replica of reality, or merely a miniaturized version of what one would see from the air. Those who make intensive use of cartography know on the contrary that any map is a pervasively conventional representation. They also know that an indefinite number of different maps of the same area can be made for different purposes, yet all may be equally valid representations of the same natural reality. Even where such maps prove mistaken, they are always corrigible; but it makes no sense to talk of ever achieving a uniquely “perfect” representation, or a complete “correspondence” with reality, since different kinds of maps are designed for different uses, and there is no limit to the further representations that may be needed for new and unforeseen purposes.”

As field geologists know, any map is both a collection of data and an expression of theory. The theory is one answer to the underlying question that drives the science.

Global society today is caught up in a transformational process, the sharp point of the wedge of transformation being economic/financial. The maps/theories that have served as guides to the future for the past several decades are failing us. It is not that Atlas has finally shrugged. But rather he seems be showing himself as an old fool.

Pay heed to what Rudwick is saying. It is unsurprising to any one that maps are never “perfect”, because most of us can remember when we first started making simple maps, and frequently gave up on the process as not being attuned to our individual talents. Most people would rather write notes than draw maps.

But the notes, being just the expression of the other half of our intellect applied to the same reality, are no more perfectible than the maps. If we could remember our first stumbling attempts to express ourselves in words, we would be more humble about our word production efforts. Our grasp of the virtual nature of the world created in words, spoken, written or printed, would be more direct.

Correspondingly, we would have a greater appetite for alternative word-maps. We would look for different slants on the world. We would see the breakdown of our word-virtual image as an opportunity to look through the metaphor into reality itself a little more clearly.

But we are stuck with the fact that our memories are focused on the product of those first stumbling efforts and we can dredge up the feelings of frustration and inadequacy that surrounded that production only by great effort of internal examination. It seems to our minds that our knowledge of the world, expressed in words, actually precedes our experience in the world. In the current unfolding of historic time it is clear that this is in fact not so. It is simply an artifact of the data, the fact that our earliest memories are expressed in words.

Eclectic plagiodoxy- Let’s look for a diversity of maps , based on different slants.

Teaching geology

This morning I put that title into Google and hit the button. A typical response followed: a zillion things to sort through. Adding one more to the zillion does not seem significant, one way or the other.

I started in the Fall of 1963, the term wherein JFK got shot. The Free Speech Movement at Berkeley followed the next year, and we were off and running through the 60′s. The question hung over my head for many years: In the face of all that was going on, what was the relevance of teaching geology? Was there any significance beyond being a decent way to make a reasonable living for my family. The answer to that question emerged slowly over the decades. But that’s not my path this morning.

My first teaching assignment was in two courses: Introductory Geology and Physical Science. The latter course was basically physics, for which I was only marginally qualified to teach. Oddly enough, it was that course that was easier for me to handle than the Geology course, for which I was highly “qualified”.  The unfolding of physics from Aristotle to Newton to Einstein follows an historical narrative path that can be followed with only a little algebra. But the geology course just seemed to be a hodge-podge of assorted facts about the Earth, in spite of the then-new Gilluly text. Modern texts have Plate Tectonics commonly as an organizing theme, but I found that only marginally better. The texts present the answer without asking the question!

The physical science  course, and textbook, presented the material along an historical line, the way it was learned in the first place. The pedagogy followed the phyllogeny, so the ontogeny of the individual student unfolded in the same way. Or at least it seemed so to me as I was both learning and teaching the subject. Paradoxically, we don’t teach geology that way. Paradoxically because we ignore our own history when introducing the first historical science. “The mind grows giddy…” said Playfair. Giddy, and perhaps more than a little afraid of the abyss of time.

A plagiodox view

Recently, Michael Reiss lost his position as Director of Education for the Royal Society because of how people reacted to what some people in the press said about what he said at a recent conference. I think I have that straight.

I have read the document that he prepared and submitted ahead of time. Assuming he said orally something pretty close to what he wrote, it is clear to me that his comments were a pretext for the precipitation of the conflict, rather than a reason. “Let’s you and him fight!” is the name of that game. Given that the media makes its living, in part, by reporting on fights, their actions are understandable, if unfortunate.

Conflict is, of course, part of the living experience of any organism that lives in a social relationship based on dominance hierarchies. Every individual spends some energy working on dominance relationships as well as cooperative relationships. And every individual draws a unique balance between these two activities, cooperation vs. dominance.

The tension between “science” and “religion” draws some very intense interest in parts of the population today. That tension provokes conflict between individuals, who take up different sides in the metaphorical struggle. Whether or not the conflict will ultimately be productive is unclear.

To me, the struggle is, in part, internal and personal. And I have been a human being long enough to be convinced that all metaphorical struggles are partly projections of internal and personal struggles. The dimensions of the struggle are expressed, at least in part, by how one responds to two problems:

• What is true vs. what is not true.

• What might work vs. what we can be certain wont work.

Science is much better at answering questions in the negative. As I have said before (Not…), we can say with much greater certainty that the Earth is not flat than we can say what precise shape it actually has. It seems to me that if we take falsification seriously as a working rule of science, we have to admit that science is much more attuned to saying what is not true than saying what is true. By the same reasoning, we can say with greater certainty in any new problem situation what wont work than what will work.

In the reality of life, one is confronted with problems. It is very nice to be able to sort the possible solutions into two piles: those we are sure wont work, and all the rest. But how do we choose between the alternatives in “all the rest”?

You try to find the alternative that, if it fails and catasrophe follows, you can reconcile yourself to the consequences. That, of course, requires an inward search. And humility.