Galileo’s Experiments on Accelerated Motion

A short account of Galileo’s description of his own experiment on accelerated motion — a short account of it, the apparatus he used and the results he got.

The first argument that Salviati proves is that in accelerated motion the change in velocity is in proportion to the time (𝑣 ∝ 𝑡) since the motion began, and not in proportion to the distance covered (𝑣 ∝ 𝑠) as is believed by Sargedo.

“But for one and the same body to fall eight feet and four feet in the same time is possible only in the case of instantaneous (discontinuous) motion; but observation shows us that the motion of a falling body occupies time, and less of it in covering a distance of four feet than of eight feet; therefore it is not true that its velocity increases in proportion to the space. (Salviati)

Also, he proves that the increase in proportion is not of simple doubling but larger. They agree upon a definition of uniformly accelerated motion,

“A motion is said to be equally or uniformly accelerated when, starting from rest, its momentum receives equal increments in equal times. (Sargedo)

To this definition Salviati adds an assumption about inclined planes, this assumption is that for a given body, the increase in speed while moving down the planes of difference inclinations is equal to the height of the plane. This also includes the case if the body is dropped vertically down, it will still gain the same speed at end of the fall as it would gain from rolling on the incline This assumption makes the final speed independent on the profile of the incline. For example, in the figure below, the body falling along𝐶 → 𝐵, 𝐶 → 𝐷 and 𝐶 → 𝐴 will attain the same final speed.

This result is also proved via a thought experiment (though it might be feasible to do this experiment) for a pendulum. The pendulum rises to the height it was released from and not more.

After stating this theorem, Galileo then suggests the experimental verification of the theorem. of The actual apparatus that Galileo uses is an wooden inclined slope of following dimensions: length 12 cubits (≈ 5.5 m, 1 cubit ≈ 45.7 cm), width half-cubit and three-finger breadths thick . In this plank of wood, he creates a very smooth groove which is about a finger thick. (What was the thickness of Galileo’s fingers?) The incline of this plank are changed by lifting one end. A bronze ball is rolled in this groove and time taken for descent is noted.

“We repeated this experiment more than once in order to measure the time with an accuracy such that the deviation between two observations never exceeded one- tenth of a pulse-beat.

Then Galileo performed variations in the experiment by letting the ball go different lengths (not full) of the incline and “found that the spaces traversed were to each other as the squares of the times, and this was true for all inclinations of the plane”. Each variation was repeated hundreds of times so as to rule out any errors. Also, the fact that for different inclines the times of descent were in noted and were in agreement with the predictions.

Since there were no second resolution clocks to measure time, Galileo devised a method to measure time using water. This was not new, water clocks were used earlier also.

The basic idea was to the measure the amount of water that was collected from the start of the motion to its end. The water thus collected was weighed on a good balance.This weight of water was used as a measure of the time. A sort of calibration without actually measuring the quantity itself: “the differences and ratios of these weights gave us the differences and ratios of the times”

Galileo used a long incline, so that he could measure the time of descent with device he had. If a shorted incline was used, it would have been difficult to measure the shorter interval of time with the resolution he had. Measuring the free fall directly was next to impossible with the technology he had. Thus the extrapolation to the free fall was made continuing the pattern that was observed for the “diluted” gravity.

“You present these recondite matters with too much evidence and ease; this great facility makes them less appreciated than they would be had they been presented in a more abstruse manner. For, in my opinion, people esteem more lightly that knowledge which they acquire with so little labor than that acquired through long and obscure discussion. (Sargedo)

 

Reference

Dialogues Concerning Two New Sciences

Bertrand Russel’s proof of naïve realism being false

What is naïve realism you may ask? To put simply naïve realism is a belief that whatever you see with your senses is the reality. There is nothing more to reality than what your sense perceptions bring to you. It is a direct unmediated access to reality. There is no “interpretation” involved.

In philosophy of perception and philosophy of mind, naïve realism (also known as direct realism, perceptual realism, or common sense realism) is the idea that the senses provide us with direct awareness of objects as they really are. When referred to as direct realism, naïve realism is often contrasted with indirect realism.

Naïve Realism

To put this in other words, naïve realism fails to distinguish between the phenomenal and the physical object. That is to say, all there is to the world is how we perceive it, nothing more.

Bertrand Russel gave a one line proof of why naïve realism is false. And this is the topic of this post. Also, the proof has some implications for science education, hence the interest.

Naive realism leads to physics, and physics, if true, shows that naive realism is false. Therefore naive realism, if true, is false; therefore it is false.

As quoted in Mary Henle – On the Distinction Between the Phenomenal and the Physical Object, John M. Nicholas (ed.), Images, Perception, and Knowledge, 187-193. (1977)

Henle in her rather short essay (quoted above) on this makes various philosophically oriented arguments to show that it is an easier position to defend when we make a distinction between the two.

But considering the “proof” of Russel, I would like to bring in evidence from science education which makes it even more compelling. There is a very rich body of literature on the theme of misconceptions or alternative conceptions among students and even teachers. Many of these arise simply because of a direct interpretation of events and objects around us.

Consider a simple example of Newton’s first law of motion.

In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.

Now for the naïve realists this will never be possible, as they will never see an object going by itself without application of any force. In real world, friction will bring to halt bodies which are moving. Similar other examples from the misconceptions also do fit in this pattern. This is perhaps so because most of the science is counter-intuitive in nature. With our simple perception we can only do a limited science (perhaps create empirical laws). So one can perhaps say that learners with alternative conceptions hold naïve realist world-view (to some degree) and the role of science education is to change this.

Rotating Earth: the proofs or significance of Leon Foucault’s pendulum – Part 1

rotating-earth

In an earlier post, we had discussed proofs of the round shape of the Earth. This included some ancient and some modern proofs. There was, in general, a consensus that the shape of the Earth was spherical and not flat and the proofs were given since the time of ancient Greeks. Only in the middle ages, there seems to have been some doubt regarding the shape of the Earth. But amongst the learned people, there was never a doubt about the shape of the Earth. Counter-intuitive it may seem when you look at the near horizon, it is not that counter-intuitive. We can find direct proofs about it by looking around and observing keenly.

But the rotation of Earth proved to be a more difficult beast to tame and is highly counter-intuitive. Your daily experience does not tell you the Earth is rotating, rather intuition tells you that it is fixed and stationary. Though the idea of a moving Earth is not new, the general acceptance of the idea took a very long time. And even almost 350 years after Copernicus’ heliocentric model was accepted, a direct proof of Earth’s rotation was lacking. And this absence of definitive proof was not due to a lack of trying. Some of the greatest minds in science, mathematics and astronomy worked on this problem since Copernicus but were unable to solve it. This included likes of Galileo, Newton, Descartes, and host of incredibly talented mathematicians since the scientific revolution. Until Leon Foucaultin the mid-1800s provided not one but two direct proofs of the rotation of the Earth. In this series of posts, we will see how this happened.

When we say the movement of the Earth, we also have to distinguish between two motions that it has: first its motion about its orbit around the Sun, and second its rotational motion about its own axis. So what possible observational proofs or direct evidence will allow us to detect the two motions? In this post, we will explore how our ideas regarding these two motions of the Earth evolved over time and what type of proofs were given for and against it.

Even more, there was a simple geometrical fact directly opposed to the Earth’s annual motion around the Sun and there was nothing that could directly prove its diurnal rotation. (Mikhailov, 1975)

Let us consider the two components of Earth’s motion. The first is the movement around the Sun along the orbit. The simplest proof for this component of Earth’s motion is from the parallax that we can observe for distant stars. Parallax is the relative change in position of objects when they are viewed from different locations. The simplest example of this can be seen with our own eyes.

Straighten your hand, and hold your thumb out. Observe the thumb with both the eyes open. You will see your thumb at a specific location with respect to the background objects. Now close your left eye, and look at how the position of the thumb has changed with respect to the background objects. Now open the right eye, and close the left one. What we will see is a shift in the background of the thumb. This shift is related by simple geometry to the distance between our eyes, called the baseline in astronomical parlance. Thus even a distance of the order of a few centimetres causes parallax, then if it is assumed that Earth is moving around the Sun, it should definitely cause an observable parallax in the fixed stars. And this was precisely one of the major roadblock

Earth moving around an orbit raised mechanical objections that seemed even more serious in later ages; and it raised a great astronomical difficulty immediately. If the Earth moves in a vast orbit, the pattern of fixed stars should show parallax changes during the year. (Rogers, 1960)

The history of cosmic theories … may without exaggeration be called a history of collective obsessions and controlled schizophrenias.
– Arthur Koestler, The Sleepwalkers

Though it is widely believed that Copernicus was the first to suggest a moving Earth, it is not the case. One of the earliest proponents of the rotating Earth was a Greek philosopher named Aristarchus. One of the books by Heath on Aristarchus is indeed titled Copernicus of Antiquity (Aristarchus of Samos). A longer version of the book is Aristarchus of Samos: The Ancient Copernicus. In his model of the cosmos, Aristarchus imagined the Sun at the centre and the Earth and other planets revolving around it. At the time it was proposed, it was not received well. There were philosophical and scientific reasons for rejecting the model.

aristarchus-01
Aristarchus’s model of the heliocentric Universe

First, let us look at the philosophical reasons. In ancient Greek cosmology, there was a clear and insurmountable distinction between the celestial and the terrestrial. The celestial order and bodies were believed to be perfect, as opposed to the imperfect terrestrial. After watching and recording the uninterrupted waltz of the sky over many millennia, it was believed that the heavens were unchangeable and perfect. The observations revealed that there are two types of “stars”. First the so-called “fixed stars” do not change their positions relative to each other. That is to say, their angular separation remains the same. They move together as a group across the sky. Imagination coupled with a group of stars led to the conceiving of constellations. Different civilizations imagined different heroes, animals, objects in the sky. They formed stories about the constellations. These became entwined with cultures and their myths.

telescope_0013

The second type of stars did change their positions with respect to other “fixed stars”. That is to say, they changed their angular distances with “fixed stars”. These stars, the planets, came to be called as “wandering stars” as opposed to the “fixed stars”.

Ancient Greeks called these lights πλάνητες ἀστέρες (planētes asteres, “wandering stars”) or simply πλανῆται (planētai, “wanderers”),from which today’s word “planet” was derived.

Planet

So how does one make sense of these observations? For the fixed stars, the solution is simple and elegant. One observes the set of stars rising from the east and setting to the west. And this set of stars changes across the year (which can be evidenced by changing seasons around us). And this change was found to be cyclical. Year after year, with observations spanning centuries, we found that the stars seem to be embedded on inside of a sphere, and this sphere rotates at a constant speed. This “model” explains the observed phenomena of fixed stars very well.

The unchanging nature of this cyclical process observed, as opposed to the chaotic nature on Earth, perhaps led to the idea that celestial phenomena are perfect. Also, the religious notion of associating the heavens with gods, perhaps added to them being perfect. So, in the case of perfect unchanging heavens, the speeds of celestial bodies, as evidenced by observing the celestial sphere consisting of “fixed stars” was also to be constant. And since celestial objects were considered as perfect, the two geometrical objects that were regarded as perfect the sphere and the circle were included in the scheme of heavens. To explain the observation of motion of stars through the sky, their rising from the east and setting to the west, it was hypothesized that the stars are embedded on the inside of a sphere, and this sphere rotates at a constant speed. We being fixed on the Earth, observe this rotating sphere as the rising and setting of stars. This model of the world works perfectly and formed the template for explaining the “wandering stars” also.

These two ideas, namely celestial objects placed on a circle/sphere rotating with constant speed, formed the philosophical basis of Greek cosmology which would dominate the Western world for nearly two thousand years. And why would one consider the Earth to be stationary? This is perhaps because the idea is highly counter-intuitive. All our experience tells us that the Earth is stationary. The metaphors that we use like rock-solid refer to an idea of immovable and rigid Earth. Even speculating about movement of Earth, there is no need for something that is so obviously not there. But as the history of science shows us, most of the scientific ideas, with a few exceptions, are highly counter-intuitive. And that the Earth seems to move and rotate is one of the most counter-intuitive thing that we experience in nature.

The celestial observations were correlated with happenings on the Earth. One could, for example, predict seasons as per the rising of certain stars, as was done by ancient Egyptians. Tables containing continuous observations of stars and planets covering several centuries were created and maintained by the Babylonian astronomers. It was this wealth of astronomical data, continuously covering several centuries, that became available to the ancient Greek astronomers as a result of Alexander’s conquest of Persia. Having such a wealth of data led to the formation of better theories, but with the two constraints of circles/spheres and constant speeds mentioned above.

With this background, next, we will consider the progress in these ideas.

A stabilised image of the Milky Way as seen from a moving Earth.

 

Why philosophy is so important in science education

This is a nice article whicH I have reposted from AEON…

Each semester, I teach courses on the philosophy of science to undergraduates at the University of New Hampshire. Most of the students take my courses to satisfy general education requirements, and most of them have never taken a philosophy class before.
On the first day of the semester, I try to give them an impression of what the philosophy of science is about. I begin by explaining to them that philosophy addresses issues that can’t be settled by facts alone, and that the philosophy of science is the application of this approach to the domain of science. After this, I explain some concepts that will be central to the course: induction, evidence, and method in scientific enquiry. I tell them that science proceeds by induction, the practices of drawing on past observations to make general claims about what has not yet been observed, but that philosophers see induction as inadequately justified, and therefore problematic for science. I then touch on the difficulty of deciding which evidence fits which hypothesis uniquely, and why getting this right is vital for any scientific research. I let them know that ‘the scientific method’ is not singular and straightforward, and that there are basic disputes about what scientific methodology should look like. Lastly, I stress that although these issues are ‘philosophical’, they nevertheless have real consequences for how science is done.

At this point, I’m often asked questions such as: ‘What are your qualifications?’ ‘Which school did you attend?’ and ‘Are you a scientist?’

Perhaps they ask these questions because, as a female philosopher of Jamaican extraction, I embody an unfamiliar cluster of identities, and they are curious about me. I’m sure that’s partly right, but I think that there’s more to it, because I’ve observed a similar pattern in a philosophy of science course taught by a more stereotypical professor. As a graduate student at Cornell University in New York, I served as a teaching assistant for a course on human nature and evolution. The professor who taught it made a very different physical impression than I do. He was white, male, bearded and in his 60s – the very image of academic authority. But students were skeptical of his views about science, because, as some said, disapprovingly: ‘He isn’t a scientist.’

I think that these responses have to do with concerns about the value of philosophy compared with that of science. It is no wonder that some of my students are doubtful that philosophers have anything useful to say about science. They are aware that prominent scientists have stated publicly that philosophy is irrelevant to science, if not utterly worthless and anachronistic. They know that STEM (science, technology, engineering and mathematics) education is accorded vastly greater importance than anything that the humanities have to offer.

Many of the young people who attend my classes think that philosophy is a fuzzy discipline that’s concerned only with matters of opinion, whereas science is in the business of discovering facts, delivering proofs, and disseminating objective truths. Furthermore, many of them believe that scientists can answer philosophical questions, but philosophers have no business weighing in on scientific ones.

Why do college students so often treat philosophy as wholly distinct from and subordinate to science? In my experience, four reasons stand out.

One has to do with a lack of historical awareness. College students tend to think that departmental divisions mirror sharp divisions in the world, and so they cannot appreciate that philosophy and science, as well as the purported divide between them, are dynamic human creations. Some of the subjects that are now labelled ‘science’ once fell under different headings. Physics, the most secure of the sciences, was once the purview of ‘natural philosophy’. And music was once at home in the faculty of mathematics. The scope of science has both narrowed and broadened, depending on the time and place and cultural contexts where it was practised.

Another reason has to do with concrete results. Science solves real-world problems. It gives us technology: things that we can touch, see and use. It gives us vaccines, GMO crops, and painkillers. Philosophy doesn’t seem, to the students, to have any tangibles to show. But, to the contrary, philosophical tangibles are many: Albert Einstein’s philosophical thought experiments made Cassini possible. Aristotle’s logic is the basis for computer science, which gave us laptops and smartphones. And philosophers’ work on the mind-body problem set the stage for the emergence of neuropsychology and therefore brain-imagining technology. Philosophy has always been quietly at work in the background of science.

A third reason has to do with concerns about truth, objectivity and bias. Science, students insist, is purely objective, and anyone who challenges that view must be misguided. A person is not deemed to be objective if she approaches her research with a set of background assumptions. Instead, she’s ‘ideological’. But all of us are ‘biased’ and our biases fuel the creative work of science. This issue can be difficult to address, because a naive conception of objectivity is so ingrained in the popular image of what science is. To approach it, I invite students to look at something nearby without any presuppositions. I then ask them to tell me what they see. They pause… and then recognise that they can’t interpret their experiences without drawing on prior ideas. Once they notice this, the idea that it can be appropriate to ask questions about objectivity in science ceases to be so strange.

The fourth source of students’ discomfort comes from what they take science education to be. One gets the impression that they think of science as mainly itemising the things that exist – ‘the facts’ – and of science education as teaching them what these facts are. I don’t conform to these expectations. But as a philosopher, I am mainly concerned with how these facts get selected and interpreted, why some are regarded as more significant than others, the ways in which facts are infused with presuppositions, and so on.

Students often respond to these concerns by stating impatiently that facts are facts. But to say that a thing is identical to itself is not to say anything interesting about it. What students mean to say by ‘facts are facts’ is that once we have ‘the facts’ there is no room for interpretation or disagreement.

Why do they think this way? It’s not because this is the way that science is practised but rather, because this is how science is normally taught. There are a daunting number of facts and procedures that students must master if they are to become scientifically literate, and they have only a limited amount of time in which to learn them. Scientists must design their courses to keep up with rapidly expanding empirical knowledge, and they do not have the leisure of devoting hours of class-time to questions that they probably are not trained to address. The unintended consequence is that students often come away from their classes without being aware that philosophical questions are relevant to scientific theory and practice.

But things don’t have to be this way. If the right educational platform is laid, philosophers like me will not have to work against the wind to convince our students that we have something important to say about science. For this we need assistance from our scientist colleagues, whom students see as the only legitimate purveyors of scientific knowledge. I propose an explicit division of labour. Our scientist colleagues should continue to teach the fundamentals of science, but they can help by making clear to their students that science brims with important conceptual, interpretative, methodological and ethical issues that philosophers are uniquely situated to address, and that far from being irrelevant to science, philosophical matters lie at its heart.Aeon counter – do not remove

 

Subrena E Smith

This article was originally published at Aeon and has been republished under Creative Commons.

Thomas Kuhn on the role of textbooks in science education

The single most striking feature of this [science] education is that, to an extent wholly unknown in other fields, it is conducted entirely through textbooks. Typically, undergraduate and graduate students of chemistry, physics, astronomy, geology, or biology acquire the substance of their fields from books written especially for students.

Thomas Kuhn The Essential Tension

Here Kuhn is trying to show us the nature of science education which is usually divergent from the historical processes and events which led to the currently accepted theories. Most of the textbooks rather show the content matter which makes sense conceptually in a rationally organised manner. Of course, the ideal goal, at least in the physical sciences, is to create a hypothetico-deductive model in which a given theory, its predictions, explanations and implications can be derived from some basic definitions and axioms. For example, an introductory text on motion in physics usually starts with definitions and assumptions usually of a mass point, and/or operations that are defined on it. The text does not describe the historical conditions in which this conceptual approach arose, rather it adapts a very pragmatic pedagogical approach. It defines the term and ends it there, but in this process, it redefines the conceptual history. This approach assumes that there is no pedagogical merit or role in introducing a concept in its historical context. This perhaps is also linked to Poppers distinction of the context of discovery and the context of justification. What we see is a rational reconstruction of historical processes to make sense of them in a straightforward manner.

 

 

Science Education and Textbooks

What are the worst possible ways of approaching the textbooks for teaching science? In his book Science Teaching: The Role of History and Philosophy of Science pedagogue Michael Matthews quotes (p. 51) Kenealy in this matter. Many of the textbooks of science would fall in this categorisation. The emphasis lays squarely on the content part, and that too memorized testing of it.

Kenealy characterizes the worst science texts as ones which “attempt to spraypaint their readers with an enormous amount of ‘scientific facts,’ and then test the readers’ memory recall.” He goes on to observe that:

Reading such a book is much like confronting a psychology experiment which is testing recall of a random list of nonsense words. In fact, the experience is often worse than that, because the book is a presentation that purports to make sense, but is missing so many key elements needed to understand how human beings could ever reason to such bizarre things, that the reader often blames herself or himself and feels “stupid,” and that science is only for special people who can think “that way” … such books and courses have lost a sense of coherence, a sense of plot, a sense of building to a climax, a sense of resolution. (Kenealy 1989, p. 215)

What kind of pedagogical imagination and theories will lead to the textbooks which have a complete emphasis on the “facts of science”? This pedagogical imagination also intimately linked to the kind of assessments that we will be using to test the “learning”. Now if we are satisfied by assessing our children by their ability to recall definitions and facts and derivations and being able to reproduce them in writing (handwriting) in a limited time then this is the kind of syllabus that we will end up with. Is it a wonder if students are found to be full of misconceptions or don’t even have basic ideas about science, its nature and methods being correct? What is surprising, at least for me, that even in such a situation learning still happens! Students still get some ideas right if not all.

A curriculum which does not see a point in assessing concepts has no right to lament at students not being able to understand them or lacking conceptual understanding. As Position Paper on Teaching of Science in NCF 2005 remarks

‘What is not assessed at the Board examination is never taught’

So, if the assessment is not at a conceptual level why should the students ever spend their time on understanding concepts? What good will it bring them in a system where a single mark can decide your future?

 

Round Earth: The Proofs

What is the evidence for a round Earth?

In this post, we explore some of the evidence for proving that the Earth is indeed spherical in shape (if not a perfect one), and not a flat one. Though in the current age we can all point to the images of Earth taken from space  (like the one shown below)

In the age of satellites is easy for us to dismiss the doubting minds who think that the Earth is not flat. But this was always not so. Apart from the evidence from the space age, people in the past had good evidence and arguments for believing that the Earth was indeed spherical in shape and not flat or any other shape. Somehow this misconception that all ancient people considered that the Earth was flat, was generated in nineteenth-century science books.

earth

Ancient evidence

telescope_0008

It is commonly believed that people till very recently believed that the Earth is flat and that some European explorers, by circumnavigating the Earth, proved that it was round. But this is not correct. Ancient Greeks already knew about the spherical shape of the Earth, and it forms the basis of many cosmological models that they built. This, in turn, had implications for the philosophical worldview of the ancient

Aristotle presents us with one of the first evidence for the roundedness of the Earth. For the ancient Greeks, the circle and the sphere presented the perfect form in nature. This was also tied to their worldview in which the celestial and terrestrial was demarcated from each other. The celestial bodies, which included the planets and stars were supposed to be perfect. There were seven planets known to the ancients, which included the Sun and the Moon. The planets were supposed to be spherical themselves revolving with a constant speed in circular orbits around the Earth. One of the core assumptions was that the heavens are unchangeable. So anything that was considered celestial was by definition (a) perfect (spherical or circular), (b) unchangeable (constant). So any mechanism that explained celestial phenomenon had to include these two concepts.

 

The cosmology of the ancient Greeks then was built upon these basic assumptions which were non-negotiable for them. This lead to the formation of various models based on the basic theme of a fixed Earth and planets on circular orbits moving constant speeds. Due to these assumptions and also due to some observed phenomena, led to the conclusion that Earth should also be indeed spherical.

Let us look at the arguments given by Aristotle in this regard. This is from Book II of On the Heavens.

The shape of the heaven is of necessity spherical; for that is the shape most appropriate to its substance and also by nature primary.

Part 11

With regard to the shape of each star, the most reasonable view is that they are spherical. It has been shown that it is not in their nature to move themselves, and, since nature is no wanton or random creator, clearly she will have given things which possess no movement a shape particularly unadapted to movement. Such a shape is the sphere, since it possesses no instrument of movement. Clearly then their mass will have the form of a sphere. Again, what holds of one holds of all, and the evidence of our eyes shows us that the moon is spherical. For how else should the moon as it waxes and wanes show for the most part a crescent-shaped or gibbous figure, and only at one moment a half-moon? And astronomical arguments give further confirmation; for no other hypothesis accounts for the crescent shape of the sun’s eclipses. One, then, of the heavenly bodies being spherical, clearly the rest will be spherical also.

In Part 13 of the book Aristotle talks about the shape of the Earth.

There are similar disputes about the shape of the earth. Some think it is spherical, others that it is flat and drum-shaped. For evidence they bring the fact that, as the sun rises and sets, the part concealed by the earth shows a straight and not a curved edge, whereas if the earth were spherical the line of section would have to be circular. In this they leave out of account the great distance of the sun from the earth and the great size of the circumference, which, seen from a distance on these apparently small circles appears straight. Such an appearance ought not to make them doubt the circular shape of the earth. But they have another argument. They say that because it is at rest, the earth must necessarily have this shape. For there are many different ways in which the movement or rest of the earth has been conceived.

Here we see the cognisance of the fact that the curvature tends to be linear when see it is too large. Aristotle then goes on to discard the ideas by Anaximenes, Anaxogoras and Democritus who claim that flatness of the Earth is responsible for it being still. He argues, even a spherical Earth can remain at rest. The Earth being at rest and it being spherical are related. In Part 14 he takes this discussion further. The first argument uses the symmetry of weight distribution.

Its shape must necessarily be spherical. For every portion of earth has weight until it reaches the centre, and the jostling of parts greater and smaller would bring about not a waved surface, but rather compression and convergence of part and part until the centre is reached.

He further argues using reasoning of additional weight distribution how a spherical Earth can still be

If the Earth was generated, then, it must have been formed in this way, and so clearly its generation was spherical; and if it is ungenerated and has remained so always, its character must be that which the initial generation, if it had occurred, would have given it. But the spherical shape, necessitated by this argument, follows also from the fact that the motions of heavy bodies always make equal angles, and are not parallel. This would be the natural form of movement towards what is naturally spherical. Either then the earth is spherical or it is at least naturally spherical.

After this, he looks at evidence from lunar eclipses to reason that Earth is indeed spherical.

eclipse

The evidence of the senses further corroborates this. How else would eclipses of the moon show segments shaped as we see them? As it is, the shapes which the moon itself each month shows are of every kind straight, gibbous, and concave-but in eclipses the outline is always curved: and, since it is the interposition of the earth that makes the eclipse, the form of this line will be caused by the form of the earth’s surface, which is therefore spherical.

Finally Aristotle takes into account the fact that stars change their positions in the sky relative to the horizon when we move to North or South, indicating that we are indeed on a spherical surface. This will not happen on a flat surface.

stars

Again, our observations of the stars make it evident, not only that the earth is circular, but also that it is a circle of no great size. For quite a small change of position to south or north causes a manifest alteration of the horizon. There is much change, I mean, in the stars which are overhead, and the stars seen are different, as one moves northward or southward. Indeed there are some stars seen in Egypt and in the neighbourhood of Cyprus which are not seen in the northerly regions; and stars, which in the north are never beyond the range of observation, in those regions rise and set. All of which goes to show not only that the earth is circular in shape, but also that it is a sphere of no great size: for otherwise the effect of so slight a change of place would not be quickly apparent.

Another evidence which can be seen since antiquity is that the masts of the ships on ocean became visible first on the horizon, the ship appear later. This can be simply explained by assuming that the surface of the ocean is curved too.

telescope_0010

Thus we have seen the ancient evidence for a spherical Earth. It was well known and well established fact, both theoretically and empirically.

Images from:

All About The Telescope – P. Klushantsev

A Book About Stars and Planets – Y. Levitan

Physics for The Inquiring Mind – Eric Rogers.

 

The Textbook League

I came across this site while reading an article, there are interesting reviews of textbooks used in schools. And some of these reviews are gory, splitting out the blood and guts of the textbooks and their inaneness. Hopefully, many people will find it useful, though the latest book that is reviewed is from about 2002. Perhaps one should do a similar thing for books in the Indian context, basically performing a post-mortem on the zombiesque textbooks that flood our schools.

The Web site of The Textbook League is a resource for middle-school and high-school educators. It provides commentaries on some 200 items, including textbooks, curriculum manuals, videos and reference books. Most of the commentaries appeared originally in the League’s bulletin, The Textbook Letter.

http://www.textbookleague.org/ttlindex.htm

Politics Science Education or Science Education Politics or Science Politics Education

I am rather not sure what should be the exact title of this
post. Apart from the two options above it could have been any other
combination of these three words. Because I would be talking about all
three of them in interdependent manner.

If someone tells you that education is or should be independent of politics they, I would say they are very naive in their view about society. Education in general and formalised education in particular, which is supported and implemented by state is about political ideology that we want our next generation to have. One of the Marxian critique of state formalised education is that it keeps the current hierarchical structures untouched in its approach and thus sustains them. Now when we come to science education we get a bit more involved about ideas.

Science by itself was at one point of time assumed to be value-neutral. This line of though can be seen in the essays that some of us wrote in the schools with titles like “Science: good or bad”. Typically the line of argument in such is that by itself science is neither good or bad, but how we put it to use is what determines whether it is good or bad. Examples to substantiate the arguments typically involve some horrific incidents like the atomic bomb on one hand and life saving drugs on the other hand. But by itself, science is not about good or bad values. It is assumed to be neutral in that sense (there are other notions of value-neutrality of science which we will consider later). Scientific thought and its products are considered above petty issues of society and indiduals, it seemed to be an quest for eternal truth. No one questioned the processes or products of science which were assumed to be the most noble, rational, logical and superior way of doing things. But this pretty picture about scientific enterprise was broken by Thomas Kuhn. What we were looking at so far is the “normative” idea of science. That is we create some ideals about science and work under the assumption that this is how actual science is or ought to be. What Kuhn in his seminal work titled The Structure of Scientific Revolution was to challenge such a normative view, instead he did a historical analysis of how science is actually done ans gave us a “descriptive” picture about science, which was based on historical facts. Keeping up the name of the book, it actually revolutionised the way we look at science.

Now keeping in mind this disctinction between “normative” and “descriptive” views is very important. This is not only true for science but also for all other forms of human endeavours. People often tend to confuse or combine the two or many times are not even aware of the difference.

After Kuhn’s groundbreaking work entire new view about science its processes and products emerged. Various aspects of the scientific enterprise which were initially thought about outside purview of science or not affecting science came in to spotlight. Science was dissected and deconstructed from various points of view. Over the next few decades these ideas emerged into full fledged disciplies on their own. Some very valid criticisms of the scientific enterprise were developed and agreed upon. For example, the idea that there exists “the scientific method” was serisously looked into and was found to be too naive. A modified view was adopted in this regard and most of philosophers of science agreed that this is too restrictive a view. Added to this the post-modernist views about science may seem strange and bizzare at times to the uninitiated. This led to what many call as the “science-wars” between scientific realists and postmodernists. The scientific realists who believe that the world described by science is the real world as it is, independent of what it might be. So in this view it implies that there is objective truth in science and the world it describes is real. This view also implies that there is something like “scientific method” and it role in creating true knowledge about the world is paramount. On the other hand postmodernist critics don’t necessarily agree with this view of the world. For example they question the very idea of objectivity of the scientific world-view. Deriving their own meaning into writings of Kuhn (which he didn’t agree to) they claimed that science itself is a social construct and has nothing to do with the real world. The apparent supremacy of “scientific-method” in creating knowledge or presenting us about the world-views is questioned. The entire scientific enterprise from processes to products was deciphered from dimensions of gender, sexual orientation, race and class. Now, when you are teaching about science to learners there should be an awareness about these issues. Some of the issues are usually overlooked or have a logical positivist nature in them. Many philosophers lament that though considerable change has happened in ideas regarding scientific enterprise especially in philosophy of science, it seems corresponding ideas in science education are not up to date. And this can be seen when you look at the science textbook with a critical focus.

With this background I will go into the reasons that made me write this post and the peculiar multi-title. It seems for post-modernists and some others that learning about politics of science is more important than learning science itself. And they feel this is the neutral view and there is nothing political about it. They look at science as an hierarchical enterprise where gender, class and race play the decisive role, hence everyone should know about it. I am not against sharing the fact with learners of science that there are other world-views, what I am against is to share only a peculiar world view which is shaped completely by one’s ideology and politcal stance rather than by actual contents. Many of the people don’t actually know science, yet they feel that they are fully justified to criticise it. And most of these people would fall on the left side of the political spectrum (at least that is what their self-image is). But the way I see it is that these same people are no different from the right-wingers who burn books without reading them. The pomos may think of themselves as intellectually superior to the tilak-sporting people but they are not. Such is the state of intellectuals that they feel threatened by exclusion of certain articles or inclusion of certain other ones in reading courses. They then use all their might to restore the “balance”. At the same time they also tell us only they have some esoteric knowledge about these issues which people like me cannot have. And no matter what I do I will never be able to do what they can. Perhaps they have super powers which I don’t know about, perhaps in their subjective world view the pigs can fly and this fact can be proven by using other methods than the scientific ones. Last point I want to make in this is inspite of all the criticims of science and its products it doesn’t stop these people from refraining use of these products and technologies! This is hypocrisy, they will curse the phone or the computer if it doesn’t work, what they perhaps don’t realise is that it might be working just that the pomos are not able to see it in their worldview.

Time Lapse Film Using Scanner

In this post we will see how to make  a time-lapse animation of something which changes over time, with a scanner. Most probably you have seen some amazing time -lapse photography of different objects. Common examples include the ever changing skyscape, blooming flowers, metamorphosing insects etc. I wanted to do a similar stuff, but due to my lethargy and other reasons I did not. Though the cameras have intervelometer, and I have used it once to take photos of a lunar eclipse, (moon changing position which I was supposed to merge later, but never did), and wanted to do the same with a blooming of a flower. But as Ghalib has said, they were one of those हज़ारों ख्वाहिशें…

The roots of the idea what follows are germinated long back, when I had a scanner. It was a basic HP 3200 scanner. That time I did not have a digital camera, (c. 2002-2003), but then I used the scanner as a camera. I had this project lined up for making collages of different cereals. Though I got a few good images from botanical samples (a dried fern below) as well and also fractals from a sheet of rusting iron. Then, I sort of forget about it.

white-fern-00

Coming to now, I saw some amazing works of art done by scanning flowers. I remembered what had been done a few years back and combined this with the amazing time-lapse sequences that I had seen , the germ began can we combine the two?

http://vimeo.com/22439234

Can we make the scanner, make scans at regular intervals, and make a animation from the resulting images. Scanning images with a scanner would solve problem of uniform lighting, for which you may require an artificial light setup. So began the task to make this possible. One obvious and most easy way to do this is to scan the images manually, lets say every 15 minutes. In this case you setup the scanner, and just press the scan button. Though this is possible, but its not how the computers should be used. In this case we are working for the computer, let us think of making the computer do work for us. In comes shell scripting to our rescue. The support for scanners in GNU/Linux is due to the SANE (Scanner Access Now Easy) Project. the GUI for the SANE is the xsane, which we have talked about in a previous post on scanning books and scanimage is the terminal option for the sane project.

The rough idea for the project is this :

1. Use scanimage to acquire images

2. Use some script to make this done at regular time intervals.

3. Once the images are with use, combine them to make a time-lapse movie

For the script part, crontab is what is mostly used for scheduling tasks, which you want to be repeated at regular intervals. So the project then became of combining crontab and scanimage. Scanimage has a mode called --batch in which you can specify the number of images that you want to scan and also provides you with renaming options. Some people have already made bash scripts for ADF (Automatic Document Feeders), you can see the example here. But there seems to be no option for delay between the scans, which is precisely what we wanted. To approach it in another way is to introduce the the scanimage command in a shell script, which would be in a loop for the required number of images and you use the sleep command for the desired time intervals, this approach does not need the crontab for its operation. But with I decided to proceed with the crontab approach.

The first thing that was needed was to get a hang of the scanimage options. So if your scanner is already supported by SANE, then you are good to go.

$scanimage -L

This will list out the devices available for scanning. In my case the scanner is Canon Lide 110, which took some efforts to get detected. For knowing how to install this scanner, if it is not automatically supported on your GNU/Linux system, please see here.

In my case it lists out something like this:

device `genesys:libusb:002:007' is a Canon LiDE 110 flatbed scanner

If there are more than one devices attached to the system the -L option will show you that. Now coming to the scan, in the scanimage programme, we have many options which control various parameters of the scanned picture. For example we can set the size, dpi, colour mode, output type, contrast etc. For a complete set of options you can go here or just type man scanimage at the terminal. We will be using very limited options for this project, namely the x, y size, mode, format, and the resolution in dpi.

Lets see what the following command does:

$scanimage -d genesys:libusb:002:006 -x 216 -y 300 --resolution 600dpi --mode Color --format=tiff>output.tiff

-d option specifies the device to be used, if there is nothing specified, scanimage takes the first device in the list which you get with -L option.

-x 216 and -y 300 options specify the size of the final image. If for example you give 500 for both x and y, scanimage will tell us that maximum x and y are these and will use those values. Adjusting these two values you will be able to ‘select’ the area to be scanned. In the above example the entire scan area is used.

--resolution option is straight forward , it sets the resolution of the image, here we have set it to 600dpi.

--mode option specifies the colour space of the output, it can be Color, Gray or Lineart

--format option chooses the output of the format, here we have chosen tiff, by default it is .pnm .

The > character tells scanimage that the scan should be output to a file called “output.tiff”, by default this will in the directory from where the command is run. For example if your command is run from the /home/user/ directory, the output.tiff will be placed there.

With these commands we are almost done with the scanimage part of the project. With this much code, we can manually scan the images every 15 minutes. But in this case it will rewrite the existing image. So what we need to do is to make sure that the filename for each scan is different. In the --batch mode scanimage takes care of this by itself, but since we are not using the batch mode we need to do something about it.

What we basically need is a counter, which should be appended to the final line of the above code.

For example let us have a variable n, we start with n=1, and each time a scan happens this variable should increment by 1. And in the output, we use this variable in the file name.

For example, filename = out$n.tiff:

n =1 | filename = out1.tiff

n = n + 1

n = 2 | filename = out2.tiff

n = n + 1

n = 3 and so on…

We can have this variable within the script only, but since we are planning to use crontab, each time the script gets called, the variable will be initialized, and it will not do the function we intend it to do. For this we need to store variable outside the script, from where it will be called and will be written into. Some googling and landed on this site, which was very helpful to attain what I wanted to. Author says that he hasn’t found any use for the script, but I have 🙂 As explained in the site above this script is basically a counter, which creates a file nvalue. starting from n=0, values are written in this file, and each time the script is executed, this file with n=n+1 is updated.

So what I did is appended the above scanimage code to the ncounter script and the result looks something like this:

#!/bin/bash
nfilename="./nvalue"
n=0
touch $nfilename
. $nfilename
n=$(expr $n + 1)
echo "n=$n" > $nfilename
scanimage -x 80 -y 60 --resolution 600dpi --mode Color --format=tiff>out"$n".tiff

What this will attain is that every time this script is run, it will create a separate output file, depending on the value of n. We put these lines of code  in a file and call it time-lapse.sh

Now to run this file we need to make it executable, for this use:

$chmod +x time-lapse.sh

and to run the script:

$./time-lapse.sh

If  everything is right, you will get a file named out1.tiff as output, running the script again you will have out2.tiff as the output. Thus we have attained what we had wanted. Now everytime the script runs we get a new file, which was desired. With this the scanimage part is done, and now we come to the part where we are scheduling the scans. For this we use the crontab, which is a powerful tool for scheduling jobs. Some good and basic tutorials for crontab can be found here and here.

To edit your crontab use:

$crontab -e

If you are using crontab for the first time, it will ask for editor of choice which has nano, vi and emacs. For me emacs is the editor of choice.

So to run scans every 15 minutes my crontab looks like this:

# m h  dom mon dow   command
*/15 * * * * /home/yourusername/time-lapse.sh

And I had tough time when nothing was happenning with crontab. Though the script was running correctly in the terminal. So finally the tip of adding in the cronfile

SHELL=/bin/bash

solved the problem. But it took me some effort to land up on exact cause of the problem and in many places there were sermons on setting PATH and other things in the script but, I did not understand what they meant.

Okay, so far so good. Once you put this script in the crontab and keep the scanner connected, it will produce scans every 15 minutes. If you are scanning in colour at high resolution, make sure you have enough free disk space.

Once the scans have run for the time that you want them , lets say 3 days. You will have a bunch of files which are the time lapse images.  For this we use the ffmpeg and ImageMagick to help us out.

Equity Over Excellence

There is an interesting piece in The Atlantic by Sergey Ivanov on the education system in Finland. Though the article is written from a viewpoint of an American, there are a lot of take home points for everyone and particularly for India. In this post I am trying to make sense of this article from an Indian standpoint. Through out the post if you just insert India for America (which I have done at places), it at once catches. For the problems Indians are facing are also the problems of the Americans, as we have more or less tried to follow their model of education. The basic theme that underlies the article
is this:

The Scandinavian country is an education superpower because 
 it values equality more than excellence.

To many in the Indian context who believe that excellence must be given priority over equity this might be surprising. Surprising because it undermines a basic premise in their logic: that to excel in science and technology the only way is to promote excellence. In India there have been two distinct approaches to education, there is a clear stratification of the students based on standardized tests, and it is these tests which filter out students. But as the Finnish experience shows us that this need not be the case.

The newly found fame for Finland’s educational system comes after excellence of their students in the PISA scores since 2000. This seems paradoxical when we learn more about the educational system. The tried and trusted formulae of instructionism and rote-learning, which many people swear by, have almost no place there. The Finnish educational system seems like an educational philosophers utopian materialized in the real world.

To understand why it is working, the way it is, Indians will have to give away their long cherished beliefs about educational system. This would make the government more accountable towards education of the people. This is not just cosmetic school reform, but a revamping of the complete educational philosophy with which we are running the show.

One of the most intriguing (at least for me) things to notice is:

“Oh,” he mentioned at one point, “and there are no private schools in
Finland.”

This notion may seem difficult for an American (Indian?) to digest, but it’s true. Only a small number of independent schools exist in Finland, and even they are all publicly financed. None is allowed to charge tuition fees. There are no private universities, either. This means that practically every person in Finland attends public school, whether for pre-K or a Ph.D.

(emphasis added)

Now, this is interesting. What can we say about India? In fact over the years there has been general trend that we are seeing, that the number of private schools is increasing. And then there are branded schools which are spreading their networks across the country. Not to tell that they charge really hefty fees, and are meant for the elite. And so is the case with the colleges, each professional degree has a price tag, only people who can afford it, get those degrees. The haves not, the non-elites, who are mostly from the deprived classes, remain with almost no education. The government keeps on talking about reaching out to people, and by allowing the private schools colleges to exist, it is actually preventing people from joining in. Another aspect about this is that since there are alternatives to the government schools, the government schools themselves have no pressure to perform. And as any intelligent parents will tell you, it is better to put your child in a private school than a government one. Most of the parents who are in a financial position to put their children in private schools, do so.

How many parents do you know who have enrolled their children in government schools, even when they can afford private schools?

There was yet another interesting piece If You Send Your Kid to Private School, You Are a Bad Person in which the author makes a case that it is parents who are driving the change of declining government schools. If the educated parents make a sustained effort of challenging and helping government schools to improve, they will surely improve. The parents adopt the path of least effort, and send their children to private schools, which are supposed to be better. This automatically creates a class divide without asking.

Even among the private schools there is an hierarchy. There are international schools, convent schools etc. So the social stratification that exists, is just reflected in the school system. Seen from this perspective, one can understand why are the government schools neglected. They are neglected because the people who are influential and who are amongst the rich and powerful are never affected by the dismal state of the government schools. They have an alternate avenue for their children where these schools never come into picture.

There is another thing that is striking in the Indian system, that is of the coaching classes. I do not know if they are present in Finland or even anywhere in the world. But in India, the coaching classes have a complete parallel system of cracking the educational system. The amount money that the coaching classes do attract must be comparable to the amount Government of India spends on education. This is another avenue where the class divide comes in. Only people with enough finances can afford to send their children to the best coaching classes. But the more fundamental question to ask is:

Why do coaching classes exist in the first place?

The answer to this question is not easy and it related closely to the way in which Indians look at education and its practices. The coaching classes exist because there is a demand for them. And what do coaching classes achieve. Most of the coaching classes are aimed at helping students crack some standardized test or the other. But why do you need standardized tests? Some of the rhetorical questions that one might ask against this question are:

From his (Sasi’s) point of view, Americans (Indians) are consistently obsessed
with certain questions:

+ How can you keep track of students’ performance if you don’t test
them constantly?
+ How can you improve teaching if you have no accountability for bad
teachers or merit pay for good teachers?
+ How do you foster competition and engage the private sector?
+ How do you provide school choice?

The answers Finland provides seem to run counter to just about everything America’s (India’s) school reformers are trying to do. For example the introduction of CCE or Continuous and Comprehensive Examination introduced as part of NCF 2005 is one such reform. Similarly we have incentives in forms of awards for best teachers, and of course the best students get rewards like getting admission to the best colleges. Their parents are proud, schools are proud, and their coaching classes are also proud. This can be seen by the number of advertisements the coaching classes put up. But all the exams like IIT-JEE, AIEEE, Medical Exams, Olympiads, etc. are standardized tests. These are the parameters of excellence in the country. Similar tests are also found in the US, like GRE, TOEFL, SAT etc. One would assume the standardized tests in Finland would be of very great quality, but in reality they don’t exist there.

For starters, Finland has no standardized tests. The only exception is what’s called the National Matriculation Exam, which everyone takes at the end of a voluntary upper-secondary school, roughly the equivalent of American high school.

The very idea of standardized tests emerged in the shadow of the Second World War. The mass recruitment of troops required a mass approach, which resulted in production of tests. In his book The Tyranny of Testing physicist Banesh Hoffman, criticises the standardized tests that were prevalent in the US, and takes to task the leading makers of these tests on the fundamental premise of their objectivity. Similarly one can, question the fundamentals of the standardized tests in the country.

Can any standardized test be really objective?

Personally, I do not think so. None of the standardized tests, take into account multiple factors that a student has skills in. These tests make the process of filtering students easier for the administrators. But do they help students at all (except for getting admission to a desired institute)? Do they really test the understanding of the subject matter? Do they take into account various social factors that is part of the mileu of the students? As Banesh Hoffman says the only thing objective about these tests is that once, the students fills in the answer sheet, the grading is objective. But why is that the teachers who are actually teaching the students cannot test them? Why do we need standardized tests to test the students?

And here comes in the idea of academic flexibility in the schools. In India even most university department do not have academic flexibility. There is a central committee which decides, what is to be taught and a committee sets a test with which we grade the students. This creates a definite goal in form of “completing the syllabus” for the teachers. This is a malice which pervades the educational system of India from primary schools to university departments. The teachers are in a race to reach the finish line of the syllabus, because if they do not, the students might face questions which they were not taught.

Though the teacher is the representative of the entire educational system in the classroom, they are nothing more than, to use a term by Krishna Kumar, “meek dictators” in the classroom. The real dictators are adminitrators and decision makers sitting at the top of the educational system. This perhaps is a colonial mentality which has been deeply embodied in the Indian psyche. But in Finland what happens:

Instead, the public school system’s teachers are trained to assess children in classrooms using independent tests they create themselves. All children receive a report card at the end of each semester, but these reports are based on individualized grading by each teacher. Periodically, the Ministry of Education tracks national progress by testing a few sample groups across a range of different schools.

People say that then the teachers cannot be trusted that they will grade their students correctly. So how will they be held accountable?

As for accountability of teachers and administrators, Sahlberg shrugs. “There’s no word for accountability in Finnish,” he later told
an audience at the Teachers College of Columbia University. “Accountability is something that is left when responsibility has been subtracted.”

For Sahlberg what matters is that in Finland all teachers and administrators are given prestige, decent pay, and a lot of responsibility. A master’s degree is required to enter the profession, and teacher training programs are among the most selective professional schools in the country. If a teacher is bad, it is the principal’s responsibility to notice and deal with it.

This is where the responsibility of the Government comes in. Goverment slowly is trying to distance itself from its role in providing education to all its citizens. But if teachers are themselves left unsatisfied both monetarily and ideologically??, what results one can
expect. In this way the Government is indirectly encouraging the private schools and coaching classes, and thus making the class divide even more striking.

And while Americans (Indians) love to talk about competition, Sahlberg points out that nothing makes Finns more uncomfortable. In his book Sahlberg quotes a line from Finnish writer named Samuli Paronen: “Real winners do not compete.” It’s hard to think of a more un-American (Indian) idea, but when it comes to education, Finland’s success shows that the Finnish attitude might have merits. There are no lists of best schools or teachers in Finland. The main driver of education policy is not competition between teachers and between schools, but cooperation.

Compare this with the Indian attitude. Competition seems to be the key to everything and especially education. Where does collaboration of
cooperation enter in Indian educational scenario?

Finally, in Finland, school choice is noticeably not a priority, nor is engaging the private sector at all. Which brings us back to the silence after Sahlberg’s comment at the Dwight School that schools like Dwight don’t exist in Finland.

“Here in America (India), parents can choose to take their kids to private schools. It’s the same idea of a marketplace that applies to, say, shops. Schools are a shop and parents can buy what ever they want. In Finland parents can also choose. But the options are all the same.”

And in India there are coaching classes which prepare students to get into better coaching classes. With both private schools and the coaching class industry around the education and related services have been commercialised to furthest extent possible. This just works in the favour of the already existing class divide. Parents do choose best for their children, and thus do perpetuate the divide as they have no other choices.

Decades ago, when the Finnish school system was badly in need of reform, the goal of the program that Finland instituted, resulting in so much success today, was never excellence. It was equity.

This is the state of the educational system in India now. And with the over emphasis on the excellence part which addresses a small set of mostly elite students, the goal should be creating equal opportunities for equity. The idea of equity in the academic circles is unfortunately equated with that of sub-standard or below average. There are people who will tell you, that “Look, there are bright students, and they need special coaching.” The government has to spend the money of bright students, so as to make the country excel in education. This is done at the expense of the average students. One may ask the question, how in the first place do you know a student is bright? The answer comes from scores of the standardized tests, which are the root cause of many problems that the educational system in India is facing now. If one is serious about changing the educational scenario in the country this has to be addressed. Though there are champions of the standardized tests, in India as in the US of Amerika, they are the ones whose existence is based on such tests. Without these tests their existence becomes meaningless. It will certainly increase the workload of lot many people a lot many times. But the problems of magnitude of changing educational system in India is no mean problem and will require solutions of these magnitudes.

Since the 1980s, the main driver of Finnish education policy has been the idea that every child should have exactly the same opportunity to
learn, regardless of family background, income, or geographic location.

In the Indian scenario this seems to have been forgotten. And one of the main reasons for this is the presence of private schools and coaching classes where parents can shop for education.

Education has been seen first and foremost not as a way to produce star performers, but as an instrument to even out social inequality.

This particular quote is exactly opposite of what the Indian
educational system does by promoting academic excellence over equity.
And this also relates to the qualities that Indians cherish. If good
education is equated with chances of making good money, then we know
where we are wrong. With private schools and coaching classes the
education of a student becomes a balance sheet, which will be brought
to green from red by the money that student will make after
completing education.

In the Finnish view, as Sahlberg describes it, this means that schools should be healthy, safe environments for children. This starts with
the basics. Finland offers all pupils free school meals, easy access to health care, psychological counseling, and individualized student
guidance.

In case of India we have seen implementation of the mid-day meal scheme. But does it extend to the other domains?

In fact, since academic excellence wasn’t a particular priority on the Finnish to-do list, when Finland’s students scored so high on the
first PISA survey in 2001, many Finns thought the results must be a mistake. But subsequent PISA tests confirmed that Finland — unlike,
say, very similar countries such as Norway — was producing academic excellence through its particular policy focus on equity.

And with so much emphasis on coming on top of the class in India, we are getting what we are sowing. Surveys will tell you that students,
including even those from the best private schools in the country do fail in simple evaluation. But is this unexpected? If the entire
focus of the educational system is to pass standardized tests, why should we expect our students to be better in something else?

That this point is almost always ignored or brushed aside in the U.S. (India) seems especially poignant at the moment, after the financial crisis and Occupy Wall Street movement have brought the problems of inequality in America into such sharp focus. The chasm between those who can afford $35,000 in tuition per child per year — or even just the price of a house in a good public school district — and the other “99 percent” is painfully plain to see.

Though India is yet to undergo Occupy BSE protests, it is not long before this happens.

Some people may point out that Finland is a developed nation. It is much more homogeneous as compared to India. Here it might become more complicated than in the US, but the central argument should hold through.

Yet Sahlberg doesn’t think that questions of size or homogeneity should give Americans (Indians) reason to dismiss the Finnish example. Finland is a relatively homogeneous country — as of 2010, just 4.6 percent of Finnish residents had been born in another country, compared with 12.7 percent in the United States. But the number of foreign-born residents in Finland doubled during the decade leading up to 2010, and the country didn’t lose its edge in education. Immigrants tended to concentrate in certain areas, causing some schools to become much more mixed than others, yet there has not been much change in the remarkable lack of variation between Finnish schools in the PISA surveys across the same period.

The social conditions in India do not match those in Finland. We have many factors like, caste and religion, which do strongly affect our educational policies in practice, if not in theory. So is this comparison valid? But comparing Finland with an country whose demographics are similar, namely Norway, we find different results. Which shows it is the educational policy which determines the outcome, and not the demographics.

Like Finland, Norway is small and not especially diverse overall, but unlike Finland it has taken an approach to education that is more American than Finnish. The result? Mediocre performance in the PISA survey. Educational policy, Abrams suggests, is probably more important to the success of a country’s school system than the nation’s size or ethnic makeup.

And time and again it is said that India does not have enough money to spend on its enormous population. Looking at the amount of GDP that is spent on education India ranks spends 3.1% of GDP on education (2006), while the US spends 5.5% (2007) and Finland 5.9% (2007). A more updated list shows this hasn’t changed much in the intervening years. A look at the graph below from the World Bank Data on these matters makes the picture clear. Though Norway spends more than Finland on education, the results are poor. So if we assume that this is the control then it clearly shows it is not the amount of money you spend or your socio-economic status of the people that matter. What matters most is the way in which you have planned for education and its spending.

gdp-educationPeople tell you that most problems in Indian education system will go away if we have enough teachers! But why are not there enough teachers one may ask? Isn’t it funny that in a country which has second largest population in the world, we do not have enough government teachers? It is surely not a problem of human resources, but of will, both political and social. We do not want to spend more on education, and yet we expect the things to be better. And somehow government is willing to spend on private partners for education, a sort of outsourcing if you want. And with more and more Public Private Partnerships for education, government is just abdicating its responsibility, in the field of education as in other fields.

Finland’s experience suggests that to win at that game, a country has to prepare not just some of its population well, but all of its population well, for the new economy. To possess some of the best schools in the world might still not be good enough if there are children being left behind.

Problem in India is manifold.

“Finland’s dream was that we want to have a good public education for every child regardless of where they go to school or what kind of families they come from, and many even in Finland said it couldn’t be done.”

Clearly, many were wrong. It is possible to create equality. And perhaps even more important — as a challenge to the American (Indian) way of thinking about education reform — Finland’s experience shows that it is possible to achieve excellence by focusing not on competition, but on cooperation, and not on choice, but on equity.

(emphasis added)

The problem facing education in America (India) isn’t the ethnic diversity of the population but the economic inequality of society, and this is precisely the problem that Finnish education reform addressed. More equity at home might just be what America (India) needs to be more competitive abroad.

Most of us think that utopian ideas are not practicable. The talk about equity in education is essentially seen with that attitude. But the Finland example has just shown us that this is possible. Though it is definitely not to say that we blindly follow that model. But it seems that utopian things are possible, just that we will have to give up on long cherished notions of what we consider excellence as.

Can Stars Be Seen in Daylight?

The constellations that we saw at night half a year ago are now overhead in the daytime. Six months later they will again adorn the night sky. The sunlit atmosphere of the Earth screens them from the eye because the air particles-disperse the sun-rays more than the rays emitted by the stars. (The observer located on the top of a high mountain, with the densest and dustiest layers of- the atmosphere below, would see the brighter stars even in daytime. For instance, from the top of Mt. Ararat (5 km. high), first-magnitude stars are clearly distinguished at 2 o’clock in the afternoon; the sky is seen as having a dark blue colour.)

The following simple experiment will help explain why the stars disappear in daylight. Punch a few holes in one of the sides of a cardboard box, taking care, however, to make them resemble a familiar constellation. Having done so, glue a sheet of white paper on the outside. Place a light inside the box and take it into a dark room; lit from the inside; the holes, representing stars in the   night sky, are clearly seen. But, switch on a light in the room without extinguishing the light in the box and, lo, the artificial stars on our sheet of paper vanish without trace: “daylight” has extinguished them.

One often reads of stars being seen even in daylight from the bottom of deep mines and wells, of tall chimney-stacks and so on. Recently, however, this viewpoint, which had the backing of eminent names, was put to test and found wanting.  As a matter of   fact, none of the men who wrote on this subject, whether the Aristotle of antiquity or 19th-century Herschel, had ever bothered to observe the stars in these conditions. They quoted the testimony of a third person. But the unwisdom of relying on the testimony of
“eye-witnesses,” say in this particular field, is emphasized by the; following example. An article in an American magazine described daylight visibility of stars from the. bottom of a well as a fable. This was hotly contested by a farmer who claimed that he had seen Capella: and Algol in daytime from the floor of a  20-metre high silo. But when his claim was checked it was found that on the latitude of his farm neither of the stars was at zenith at the given date and, consequently could not have been seen from
the bottom of the silo.

Theoretically, there is no reason why a mine or a well should help in daylight observation of stars. We have already mentioned that the stars are not seen in daytime because sunlight extinguishes them. This holds also for the eye of the observer at the bottom of a mine. All that is subtracted in this case- is the light from the sides. All the particles in the layer of air above the surface of the mine continue to give off light and, consequently, bar the stars to vision.

What is of importance here is that the walls of the well protect the; eye from the bright sunlight; this, however, merely facilitates observation of the bright planets, but not the stars. The reason why stars are seen through the telescope in daylight is not because they are seen from “the bottom of a tube,” as many think, but because the refraction of light, by the lens or its reflection in the mirrors detracts from the brilliancy of the part of the sky under observation, and at the same time enhances the brilliancy of the stars (seen as points of light). We can see first-magnitude and even second-magnitude stars in daytime through a 7 cm. telescope. What has been said, however, does not hold true for either wells, mines, or chimneys.

The bright planets, say, Venus, Jupiter or Mars, in opposition, present a totally different picture. They shine far more brilliantly than the stars, and for this reason, given favourable conditions, can be seen in daylight.

From Astronomy for Entertainment – Yakov Perelman Pg: 135-137

Available here.

Does Tulsi has environmental benefits too?

Recently there was a news item in Times of India which had the same heading as that of this particular post. The news claimed

(Around two decades back Dada Dham, a socio-spiritual organization brought together a team of botanists, ayurvedic scholars and environmental enthusiasts to study the environmental benefits of tulsi.)

NAGPUR: Ayurvedic medicinal values of Tulsi are well known. Our ancient scriptures have enumerated the medicinal benefits of tulsi. Its extracts are used widely for curing common ailments like common cold, headache, stomach disorder etc.

But the environmental benefits have been comparatively unknown. Around two decades back Dada Dham, a socio-spiritual organization brought together a team of botanists, ayurvedic scholars and environmental enthusiasts to study the environmental benefits of tulsi.

Now the next claim from an “eminent botanist” that the report does is startling indeed.

“Tulsi gives out oxygen for 20 hours and ozone for four hours a day along with the formation of nascent oxygen which absorbs harmful gases like carbon monoxide, carbon dioxide and sulphur dioxide from the environment,” said Shyamkant Padoley, an eminent botanist.
How would the tulsi plant (Ocimum tenuiflorum) do this? Is it anatomically so different that it is capable to do this? How does the plant regulate this 20 and 4 hour cycle?  I would really like to know. How is that no other plants have this cycle? How did they detect presence of ozone, what detectors they used? What mechanisms in presently known cycle of photosynthesis account for this cycle? And if this is part of the standard photosynthesis process, then all plants should have it. This seems fishy, and a most preliminary search did not yield any positive result. All of them talk about production of oxygen and not ozone, as reported by Padoley. And if this is indeed true, it might lead to change in our conception of the photosynthetic cycle.
And if the ozone report is to be believed at all then this is what ozone does to you quote from Wikipedia article on ozone:
Ozone is a powerful oxidant (far more so than dioxygen) and has many industrial and consumer applications related to oxidation. This same high oxidizing potential, however, causes ozone to damage mucus and respiratory tissues in animals, and also tissues in plants, above concentrations of about 100 parts per billion. This makes ozone a potent respiratory hazard and pollutant near ground level.
There is evidence of significant reduction in agricultural yields because of increased ground-level ozone and pollution which interferes with photosynthesis and stunts overall growth of some plant species. The United States Environmental Protection Agency is proposing a secondary regulation to reduce crop damage, in addition to the primary regulation designed for the protection of human health.
There is a great deal of evidence to show that ground level ozone can harm lung function and irritate the respiratory system.Exposure to ozone and the pollutants that produce it is linked to premature death, asthma, bronchitis, heart attack, and other cardiopulmonary problems.
Ozone is air pollutant, green house gas.
To summarize this is that ozone is NOT GOOD for us at ground level! It may do us good in upper atmosphere to block UV Rays, but down here on ground it is bad. And if this claim of ozone production by Tulsi is true why is the campaign of “Tulsi lagao pradushan hatoa (Plant tulsi, remove pollution)” which follows in the article is being implemented?

Padoley, member of technical committee, ministry of environment and forest, NewDelhi, and forest tech committee, also read a paper at the International Conference on Occupational Respiratory Diseases at Kyoto in 1997 where cyclo oxygenate, an enzyme only found in tulsi was labelled for the first time. This enzyme regulates the entire mechanism of oxygen evolution. (emphasis added)

This again I am unable to understand. It says this enzyme is “only found in Tulsi”, and it also “regulates entire mechanism of oxygen evolution”. One can agree that a particular enzyme is found in a particular plant, but if this enzyme controls “entire mechanism of oxygen evolution”, how do other plants regulate their mechanisms of oxygen evolution.

Dada Dham initiated a campaign ‘Tulsi Lagao Pradushan Hatao’ in 1987 under the guidance of Narendra Dada, the institution’s head. It was under this campaign that the above mentioned panel of experts was formed. After finding out the environmental benefits of the plant, Dada Dham organized a number of programmes like street plays, nukkad sabhas and lectures to propagate the use of the plant.

Dr Dattatraya Saraf, an ayurvedic doctor and expert said, “The plant enriches the environment with oxygen almost 24X7 and also absorbs other pollutants.” He further added that if the size of the plant can be increased, the environmental benefits can be increased.

This statement that “plant enriches the environment with oxygen almost 24X7” is in contradiction to statement by above Padoley regarding 20 and 4 hour cycles. Which one is to be believed? And mind you this is just appearing a few lines later, this is either very poor editing and reporting, or hogwash to the public.

“That is why we want to urge scientists and concerned authorities to make research on the issue of increasing the height of tulsi plant. If big trees can be converted to bonsai plants then big tulsi trees can be possible too,” said Kishor Verma, PRO of Dada Dham.

This is another statement that I would like to contest. Did they compare the rate of oxygen production vis-a-vis to other plants. That is to say simply did they have any control sample? And does making “tulsi tree” make any sense (can one really do it is another question), will it really increase oxygen making capabilities, is it a linear relationship between these two variables? The water is completely muddy in this !

He also citied the research and work by other organization in support of tulsi’s environmental benefits.

“The forest department of Uttar Pradesh, with the help of an organization called Organic India Limited, Lucknow planted lakhs of tulsi saplings around Taj Mahal to protect its surface from industrial emissions. This step has yielded positive results,” Verma said.

“We are just asking the administration to take notice of these extra ordinary benefits of tulsi and take steps for utilizing them. Even simple steps like planting tulsi plants on road dividers, parks etc can bring a difference,” said Verma.

The reporter and also the editor make no effort to correct these glaring inconsistencies in the report itself, forget about doing nay research on the topic, or verifying the claims made by these people. Maybe this was like the paid news that is talked about a lot these days.

What I find here i that the agenda of what is to be done was already set, the conclusions were already drawn, by our ancestors, written in black and white in ancient texts. The point was only to justify what they were doing, and trying to provide a “scientific basis” of what they already believed to be true (for whatever reasons, mostly religious, and presence of a religious organization in this sort of confirms this).

A good example of  pseudo-science and bad science reporting.

Science, a humanistic approach

Science is an adventure of the whole human race to learn to live in and perhaps to love the universe in which they are. To be a part of it is to understand, to understand oneself, to begin to feel that there is a capacity within man far beyond what he felt he had, of an infinite extension of human possibilities . . .
I propose that science be taught at whatever level, from the lowest to the highest, in the humanistic way. It should be taught with a certain historical understanding , with a certain philosophical understanding , with a social understanding and a human understanding in the sense of the biography, the nature of the people who made this construction, the triumphs, the trials, the tribulations.

I. I. RABI
Nobel Laureate in Physics

via Project Physics Course, Unit 4 Light and Electromagnetism Preface

Do see the Project Physics Course which has come in Public Domain hosted at the Internet Archive, thanks to F.  James Rutherford.

Science And Certainty

Science is not about certainty. Science is about finding the most reliable way of thinking, at the present level of knowledge. Science is extremely reliable; it’s not certain. In fact, not only it’s not certain, but it’s the lack of certainty that grounds it. Scientific ideas are credible not because they are sure, but because they are the ones that have survived all the possible past critiques, and they are the most credible because they were put on the table for everybody’s criticism.

The very expression ‘scientifically proven’ is a contradiction in terms. There is nothing that is scientifically proven. The core of science is the deep awareness that we have wrong ideas, we have prejudices. We have ingrained prejudices. In our conceptual structure for grasping reality there might be something not appropriate, something we may have to revise to understand better. So at any moment, we have a vision of reality that is effective, it’s good, it’s the best we have found so far. It’s the most credible we have found so far, its mostly correct.

via | Edge

This is something that I think separates science from religion. Religion is about absolutes, trust in the absolute God. And this is the difference that should be also taught to the students of science.

Reason and Faith – Misconceptions in Science Education

Reason does not work in matters of faith. But it may have a chance at clearing misconceptions.

via Tehelka

Truly so. In case of my field of study, namely science education research, it may be the other way round. The classic studies in science education aim at identifying the misconceptions that the learners have regarding a particular subject and then finding a mechanism by which they could be addressed.

This was a very simple but very basic presentation of  what most studies try to achieve, though the methodology may be different. There are some studies which present us with a conceptual framework so that all the responses and the problems with the learners can be seen in light of a theoretical construct. This they say will enable us to make sense of what we see in the classrooms, and what is present as representation in the learners mind. What I think they are trying to say is that we need to get to the conceptual structures that lead to formation of the misconceptions.

Now mind you that many of these misconceptions in science are very stubborn and people are very reluctant to give them up. The reason may be that many of these misconceptions come from direct factual experience in the real world. And from what I know about Philosophy of Science, we might want to make a case that all science is counter-intuitive to our everyday experience. This would explain why misconceptions in science arise. But would this case explain all the known misconceptions?

Let us do some analysis of how a particular misconception might arise.There can be two different reasons for a misconception to arise, if we adhere to deductive logic. That is to say we assume that we have a set of starting statements that are given, whose authenticity is not questioned. And from these set of statements we make certain deductions regarding the world out there. Now there can be two problems with this scenario, one is that the set of statements that we are taking for granted might be wrong, the other is that in the process of deduction that we have followed we made a mistake. The mistake is learnt only when the end result of our analysis is not consistent with the observations in the real world. Or it might be even the case that the so called misconception will lead to a correct answer, at least in some cases.  In these cases we have to resort to more detailed analysis of the thought structure which lead to the answers. Another identifying characteristic of the misconceptions is presence of the inconsistencies across different areas known to the learners. Whereas they might get a particular concept clearly and correctly, in applying same thing for another concept they just might revert to a completely opposite argument and in doing this they do not realise the inconsistency.

We will be clearer on this issue when we talk with a few examples. Suppose that we have a scenario in which we are trying to understand the phenomena of day and night, its causes and consequences. A typical argument in our class goes like this:

How many have seen the Sun set?

Almost all hands would go up, then comes the next question:

How many have seen the Sun rise?

Almost same number of hands go up, excepting a few, who are late risers like me. Some of the more intelligent and the more knowledgeable would say,

“Wait! Sun doesn’t rise and set, it is the Earth that is moving, so it causes the apparent motion of Sun across the sky, the start and end of which we call as day and night. So in conclusion the Sun doesn’t rise and set, it is an illusion created by motion of Earth.”

To this all of the class agrees. This is what they have learned in the text-book, and mind you the text-book represents truth and only truth, nothing else. It is there to dispel your doubts and misconceptions and is made by a committee of experts who are highly knowledgeable about these things. Now let us continue this line of reasoning and ask them the next question in this series.

Does the Moon rise? If so, does it rise everyday?

The responses to this question are mixed. Most of them would say that it does not rise, it is always there, up in the sky. Some would gather courage and say that it does rise.

Does the Moon set?

Again to this the response is mixed, and mostly negative. Most of them are adamant about the ever presence of the moon in the sky. The next question really upsets them

Do the stars rise and set?

Now this question definitely gets a negative response from almost all of them. Even the more knowledgeable ones fall. They have read different parts of the story, but have not connected them. They tell you the following: “No the stars do not move, they are there all the time.” They also tell you that there is something called as the fixed stars and this is in the text-book, which cannot be wrong. And when asked:

Why are we not able to see the stars during the day time?

They tell you “Of course you cannot see the stars during the day time. This is because our Sun, which is also a star, is too bright and the other stars too far away and hence are dim. So our Sun’s brightness, overwhelms the other stars, and hence they are not visible during the day time, but they are there nonetheless. In the night time, since the Sun is no longer visible, the stars become visible. Have you never noticed that during the evening twilight the stars become visible one by one, the brighter ones first. Whereas in the morning the brightest are the last ones to disappear.”

Of course, the things said above and the reasoning given sounds good. So much so that the respondents are convinced that they understand how things work, and have an elaborate reasoning mechanism to explain the observed things, in this case the formation of day and night and appearance / disappearance of stars during night and day respectively.

You ask them:

Don’t you think there is a problem with what you have just said?

“Where is the problem?”, they tell you. “We just explained scientifically how things are in heaven.”

Then you open the Pandora’s box,

“Well you have just said that the Sun doesn’t move really, it is the Earth that moves, and hence we see the apparent Sun rise and Sun set.”

Then they say, “Yes, that is the case. The Sun doesn’t move, but the Earth does.”

You ask, “How do you know this? Do you see that the Earth is moving?”

They say, “The textbook tells us so ” Some of the more knowledgeable ones say that “Galileo proved that the Earth moves and not the Sun. Since we are on Earth, we see only apparent motion of the Sun.”

You say: “But wait, just now you said that the Moon does not move, it is always in the sky. Also you said that the stars do not move, they are there all the time. Now if the Earth moves, then all these bodies should also move, if only, apparently.Then the stars must also move, just like the Sun does, do not forget that Sun is a star too! So other stars should also just set and rise like the Sun, and so should also the Moon!”

Or you can argue just the opposite: “I claim that it is the Sun that moves, Earth does not move. Isn’t it a lot more easier to explain this way, why we do see the Sun moving, because it moves. And we anyway do not see Earth moving! How will disprove me?”

Then the grumbles start. They have never thought about this. They knew the facts, but never connected them. This lead to the misconceptions regarding these things. They were right in parts, but never got a chance to connect the dots, metaphorically speaking.The reason for these misconceptions is the faith in the text-books, but if the text-books fail to perform the job of asking them the right question, where the reasoning alone can get rid of many of the misconceptions.

If we choose the alternative question, of challenging them to disprove that the Earth is stationary, almost most of them are unable to answer the question of disproving that the idea that the Sun moves and not Earth. They would suggest that we can see this from the satellite in the sky (Can we really?).

Most of us take the things for granted and never question many (or as in most cases, any) of them. And many times the facts are something we do not question. We say that “It is a fact.” This statement basically posits that the information which we think is out there can be unquestionable. But there are many flavours of the post-modern philosophy which challenge this position. They think that the facts themselves are relative, that is to say that one culture has different science than another one.  But let us leave this, and come back to our problem of the stars and the Sun and Moon.

Lets put out the postulates for the above arguments and try to deduce deductively the results that were obtained.

Claim 1: Sun doesn’t move.

Claim 2: Earth moves.

Observation 1: We see the Sun moving across the sky daily, it rises and it sets.

Explanation 1:  Since the Earth moves, and the Sun is stationary, we see that Sun moves apparently. This apparent motion of the Sun is seen as the Sunrise and the Sunset by us. This is what causes the day and night.

But we can have Observation 1 explained by another set of claims, which is exactly opposite, namely, that the Earth doesn’t move but the Sun moves.

Claim 3: The Sun moves.

Claim 4: The Earth does not move.

Explanation 2: Since the Earth does not move, and the Sun does, we just see the Sun passing by in the sky, around the Earth. This causes day and night.

We see that Explanations 1 and 2 are both valid for Observation 1, if the claims 1 and 2, 3 and 4 are true then the respective deductions from them, in this case the Explanations 1 and 2 respectively are also true.So in this case the logical deduction is correct, provided that the Claims or assumptions are correct. But this process does not tell you whether the claims themselves are true or not. But both set of assumptions, cannot be true at the same time. Either the Earth moves or it does not, it cannot be in a state of both. If at all we had an explanation which came from these assumptions which did not correspond with the observations, but was logically deducible, then we can question the assumptions or premises as philosophers call them.

Of course, the things said above and the reasoning given sounds good. So much so that the respondents are convinced that they
understand how things work, and have an elaborate reasoning mechanism

We can have one example of this type.

Assumption 5: Stars do not move, there are so called “fixed stars”.

Assumption 5: During the day time the Sun is too bright, as compared to the other stars.

Now in this case combining Assumption 5 (A5) with Observation 1 (Ob1) we would get the following:

Explanation 3: The stars are too dim as compared to Sun, hence we cannot see them during the day time, but they are present. Hence they do not move.

In Explanation 3 (E3) above the deduction has a problem. The deduction does not follow from the assumption. This is the other problem in which we talked about above.

Most of the people who would suggest these responses have mostly no background in astronomy. Even then the basic facts that Earth goes round the Sun and not the other way round are forced upon them, without any critical emphasis on why it is so. Neither are they presented at point with the cognitive struggle of another view point, namely the geo-centric view. So presenting the learners with opportunities that will make them observe things and make sense of the explanations in light of the assumptions that were made, will enhance the reasoning and help them to overcome some of their misconceptions.

But there is another observation which can be made of the skies. And it can be either done in the classroom with the aid of Free Softwares like Stellarium. After the round of above questions, we usually show the class the rising of the stars from the east. In a darkened room with a projector the effect is quite dramatic for those who have not witnessed such a thing before. So you can show the class, just as the Sun rises, all other celestial bodies like the Moon and the stars also must rise and this is an observed fact.

Observation 2: The stars and planets and the Moon also rise and set everyday.

So how do we make sense of this observation, Ob2 in the light of the assumptions that we have.

Assumption 6: Sun is a star.

Explanation 4: We observe that Sun moves during the day, from East to West. Sun is a star, hence all other stars should also move.

Now why this should be the case will be different for the geo-centric and the helio-centric theories. In case of H-C theory the explantion is simple. The Earth moves hence the stars appear to move in the opposite direction. And this applies to all the objects in the sky.

Since the Earth moves all other celestial objects will appear to move. In case of G-C theory we have to make an assumption that the
stars are “fixed” on some imaginary sphere, and the sphere as a whole rotates.

But coming back to the misconceptions, it is just the ad-hoc belief that the stars do not move (“fixed stars”) in conjunctions with another observation that in presence of too bright objects dim objects cannot be seen leads to belief that the stars are immobile and do not rise and set as the Sun does. There is another disconnection from another fact that they know, or are told in the textbooks, that  the apparent movement of the Sun is caused by the actual movement of  the Earth. There is no connection between these two facts which is  made explicit.

We think that providing opportunities for direct observation aided by software, Stellarium in this case, which help in visualizing the movements of celestial bodies will help in developing the skill of reasoning and explaining an observed phenomena.

On-line Education | RMS

Educators, and all those who wish to contribute to on-line educational works: please do not to let your work be made non-free. Offer your assistance and text to educational works that carry free/libre licenses, preferably copyleft licenses so that all versions of the work must respect teachers’ and students’ freedom. Then invite educational activities to use and redistribute these works on that freedom-respecting basis, if they will. Together we can make education a domain of freedom.

via On-line Education|RMS

Mostly people don’t bother about what they get for gratis on the Internet, but institutions cannot adopt the same approach. Licensing is as much important as much as the actual content. But an archaic system will not go down till it is compelled to, and it will fight till the very end.

Flying Circus of Physics…

The Flying Circus of Physics began one dark and dreary night in 1968 while I was a graduate student at the University of Maryland. Well, actually, to most graduate students nearly all nights are dark and dreary, but I mean that that particular night was really dark and dreary. I was a full-time teaching assistant, and earlier in the day I had given a quiz to Sharon, one of my students. She did badly and at the end turned to me with the challenge, “What has anything of this to do with my life?”

I jumped to respond, “Sharon, this is physics! This has everything to do with your life!”

As she turned more to face me, with eyes and voice both tightened, she said in measured pace, “Give me some examples.”

I thought and thought but could not come up with a single one. I had spent at least six years studying physics and I could not come up with even a single example.That night I realized that the trouble with Sharon was actually the trouble with me: This thing called physics was something people did in a physics building, not something that was connected with the real world of Sharon or me. So, I decided to collect some real-world examples and, to catch her attention, I called the collection The Flying Circus of Physics.

via Jearl Walker | Flying Circus of Physics

Examinations: Students, Teachers and the System

We think of exams as simple troublesome exchanges with students:

Glance at some of the uses of examinations:

  • Measure students' knowledge of facts, principles, definitions, 
    experimental methods, etc
  • Measure students' understanding of the field studied
  • Show students what they have learnt
  • Show teacher what students have learnt
  • Provide students with landmarks in their studies
  • Provide students with landmarks in their studies and check 
    their progress
  • Make comparisons among students, or among teachers, 
    or among schools
  • Act as prognostic test to direct students to careers
  • Act as diagnostic test for placing students in fast 
    or slow programs
  • Act as an incentive to encourage study
  • Encourage study by promoting competition among students
  • Certify necessary level for later jobs
  • Certify a general educational background for later jobs
  • Act as test of general intelligence for jobs
  • Award's, scholarships, prizes etc.

There is no need to read all that list; I post it only as a warning against trying to do too many different things at once. These many uses are the variables in examining business, and unless we separate the variables, or at least think about separating them, our business will continue to suffer from confusion and damage.

There are two more aspects of great importance well known but seldom mentioned. First the effect of examination on teachers and their teaching –

coercive if imposed from the outside; guiding if adopted sensibly. That is how to change a whole teaching program to new aims and methods – institute new examinations. It can affect a teacher strongly.

It can also be the way to wreck a new program – keep the old exams, or try to correlate students’ progress with success in old exams.

Second: tremendous effect on students.

Examinations tell them our real aims, at least so they believe. If we stress clear understanding and aim at growing knowledge of physics, we may completely sabotage our teaching by a final examination that asks for numbers to be put in memorized formulas. However loud our sermons, however intriguing the experiments, students will be judged by that exam – and so will next years students who hear about it.

From:

Examinations: Powerful Agents for Good or Ill in Teaching | Eric M. Rogers | Am. J. Phys. 37, 954 (1969)

Though here the real power players the bureaucrats and (highly) qualified PhDs in education or otherwise who decide what is to be taught and how it is evaluated in the classroom. They are “coercive” as Rogers points out and teachers, the meek dictators (after Krishna Kumar), are the point of contact with the students and have to face the heat from all the sides. They are more like foot soldiers most of whom have no idea of what they are doing, why they are doing; while generals in their cozy rooms, are planning how to strike the enemy (is the enemy the students or their lack of (interest in ) education, I still wonder).  In other words most of them don’t have an birds-eye-view of system that they are a focal part of.

Or as Morris Kline puts it:

A couple of years of desperate but fruitless efforts caused Peter to sit back and think. He had projected himself and his own values and he had failed. He was not reaching his students. The liberal arts students saw no value in mathematics. The mathematics majors pursued mathematics because, like Peter, they were pleased to get correct answers to problems. But there was no genuine interest in the subject. Those students who would use mathematics in some profession or career insisted on being shown immediately how the material could be useful to them. A mere assurance that they would need it did not suffice. And so Peter began to wonder whether the subject matter prescribed in the syllabi was really suitable. Perhaps, unintentionally, he was wasting his students’ time.

Peter decided to investigate the value of the material he had been asked to teach. His first recourse was to check with his colleagues, who had taught from five to twenty-five or more years. But they knew no more than Peter about what physical scientists, social scientists, engineers, and high school and elementary school teachers really ought to learn. Like himself, they merely followed syllabi – and no one knew who had written the syllabi.

Peter’s next recourse was to examine the textbooks in the field. Surely professors in other institutions had overcome the problems he faced. His first glance through publishers’ catalogues cheered him. He saw titles such as Mathematics for Liberal Arts, Mathematics for Biologists, Calculus for Social Scientists, and Applied Mathematics for Engineers. He eagerly secured copies. But the texts proved to be a crushing disappointment. Only the authors’ and publishers names seemed to differentiate them. The contents were about the same, whether the authors in their prefaces or the publishers in their advertising literature professed to address liberal arts students, prospective engineers, students of business, or prospective teachers. Motivation and use of the mathematics were entirely ignored. It was evident that these authors had no idea of what anyone did with mathematics.

From: A Critique Of Undergrduate Education. (Commonly Known As: Why The Professor Can’t Teach?) | Morris Kline

Both of the works are about 50 years old, but they still reflect the educational system as of now.

How science should be taught

Science is an adventure of the whole human race to learn to live in and
perhaps to love the universe in which they are. To be a part of it is to
understand, to understand oneself, to begin to feel that there is a capacity
within man far beyond what he felt he had, of an infinite extension of
human possibilities ….

I propose that science be taught at whatever level, from the lowest to the
highest, in the humanistic way. It should be taught with a certain historical
understanding, with a certain philosophical understanding with a social
understanding and a human understanding in the sense of the biography, the
nature of the people who made this construction, the triumphs, the trials, the tribulations.

I. I. RABI

Nobel Laureate in Physics