I was sitting around yesterday without knowing what to do. At this point I usually look towards by book shelf for inspiration. I found it yesterday when I opened the pages of Jearl Walker's "The Flying Circus of Physics". A wonderful book full of problems which the author says himself, "are for fun... What I mainly want to show here is that physics is not something that has to be done in a physics building. Physics and physics problems are in the real, everyday world that we live, work, love and die in."
Here I've stated, word for word, a very curious and interesting problem(like all the others in the book). I don't have an answer, and I haven't looked it up. Thought I'd leave it as an open question for now. And, oh, I've noticed this myself too! But never payed too much attention as I'm too sleepy in the mornings while drinking coffee, and too preoccupied in the evenings. Anyway, it goes like this-
Coffee laced with polygons
If you examine a hot cup of coffee under a strong light that is incident nearly parallel to the surface of the coffee, you will find the surface laced with polygonal cells. They disappear, however, as the coffee cools. You can also destroy the cellular appearance by putting a charged rubber comb (charge it by running it through your hair) near the coffee.
Other liquids show surface designs too. James Thomson, a famous 19th century physicist, noticed the rapidly varying surface designs in a pail of hot soapy water and in strong wines. Later, the Frenchman Bernard was able to make regular patterns in oil surfaces when the oil was heated from below. His regular polygons would slowly evolve into a beautiful hexagonal, honeycomb structure. Still other fluids gave a roll-like appearance. Recently, cellular surface designs were attempted on board spacecraft while under zero gravity.
In these examples, why do rolls and polygons (especially honeycombs) form on the fluid surface? Is the same physics actually responsible for all of the examples? Why do the coffee cells disappear when there is a charged body nearby? Finally, do these several types of surface designs depend on gravity?
The above is listed under the topics- convection, surface tension, nonlinear fluid flow, stability, condensation.
Showing posts with label science. Show all posts
Showing posts with label science. Show all posts
Thursday, September 2, 2010
Wednesday, August 25, 2010
Wonderful:) ... as a follow up to ur post i would like to show an extract from Mlodinow's, "Feynman's Rainbow"...
" When I got to him, Feynman was gazing at a rainbow. He had an intense look on his face, as if he were concentrating. As if he had never seen one before. Or maybe as if it might be his last.
I approached him cautiously.
"Professor Feynman. Hi," I said.
"Look, a rainbow," he said without looking at me.
I joined him in staring at the rainbow. It appeared pretty impressive, if you stopped to look at it. It wasn't something I normally did-in those days.
"I wonder what the ancients thought of rainbows", I mused. There were many myths based on the stars, but I thought rainbows must have seemed equally mysterious.
"All I know," Feynman said, " is that according to one legend angels put gold at its ends and only a nude man can reach it.
"Do you know who first explained the true origin of the rainbows?" I asked.
"It was Descartes," he said. After a moment he looked me in the eye.
" And what do you think was the salient feature of the rainbows that inspired descartes' mathematical analysis?" he asked.
" Well, the rainbow is actually a section of a cone that appears as an arc of the colors of the spectrum when drops of water are illuminated by sunlight behind the observer."
"And?"
"I suppose his inspiration was the realization that the problem could be analysed by considering a single drop, and the geometry of the situation."
"You're overlooking a key feature of the phenomenon," he said.
" Okay, I give up. What would you say inspired his theory?"
"I would say his inspiration was that he thought rainbows were beautiful."
I looked at him sheepishly. He looked at me. " How's your work coming?" he asked.
I shrugged. " It's not really coming."
"Let me ask you something. Think back to when you were a kid. For you, that isn't going too far back. When you were a kid, did you love science? Was it your passion?"
I nodded. " As long as I can remember. "
"Me, too", he said. " Remember, it's supposed to be fun." And he walked on. "
Along with science being fun, I think there is a certain appreciation for beauty inherent in human beings. We cannot define beauty. What we find beautiful is usually something natural. ( Personally, I find Einstein's relativity beautiful, even if eventually it turned out to be wrong).
Curiosity may drive us to do science. The fact that it is fun is another motivation. Whatever it is, these things feed on us. Curiosity transforms itself into a strong driving force that pushes us through the greatest extents. We don't know where our search will lead us, but the journey sure is fun. In the end, I think it is the journey that matters, not the destination. And that I think is one of the most beautiful things about life and physics.
What remains to be answered about present day science is whether this is what still drives every physicist? Or have the motivations changed a bit?
" When I got to him, Feynman was gazing at a rainbow. He had an intense look on his face, as if he were concentrating. As if he had never seen one before. Or maybe as if it might be his last.
I approached him cautiously.
"Professor Feynman. Hi," I said.
"Look, a rainbow," he said without looking at me.
I joined him in staring at the rainbow. It appeared pretty impressive, if you stopped to look at it. It wasn't something I normally did-in those days.
"I wonder what the ancients thought of rainbows", I mused. There were many myths based on the stars, but I thought rainbows must have seemed equally mysterious.
"All I know," Feynman said, " is that according to one legend angels put gold at its ends and only a nude man can reach it.
"Do you know who first explained the true origin of the rainbows?" I asked.
"It was Descartes," he said. After a moment he looked me in the eye.
" And what do you think was the salient feature of the rainbows that inspired descartes' mathematical analysis?" he asked.
" Well, the rainbow is actually a section of a cone that appears as an arc of the colors of the spectrum when drops of water are illuminated by sunlight behind the observer."
"And?"
"I suppose his inspiration was the realization that the problem could be analysed by considering a single drop, and the geometry of the situation."
"You're overlooking a key feature of the phenomenon," he said.
" Okay, I give up. What would you say inspired his theory?"
"I would say his inspiration was that he thought rainbows were beautiful."
I looked at him sheepishly. He looked at me. " How's your work coming?" he asked.
I shrugged. " It's not really coming."
"Let me ask you something. Think back to when you were a kid. For you, that isn't going too far back. When you were a kid, did you love science? Was it your passion?"
I nodded. " As long as I can remember. "
"Me, too", he said. " Remember, it's supposed to be fun." And he walked on. "
Along with science being fun, I think there is a certain appreciation for beauty inherent in human beings. We cannot define beauty. What we find beautiful is usually something natural. ( Personally, I find Einstein's relativity beautiful, even if eventually it turned out to be wrong).
Curiosity may drive us to do science. The fact that it is fun is another motivation. Whatever it is, these things feed on us. Curiosity transforms itself into a strong driving force that pushes us through the greatest extents. We don't know where our search will lead us, but the journey sure is fun. In the end, I think it is the journey that matters, not the destination. And that I think is one of the most beautiful things about life and physics.
What remains to be answered about present day science is whether this is what still drives every physicist? Or have the motivations changed a bit?
The pursuit of science: its motivations
We have been talking about how Feynman influenced our learning of science and towards our scientific imagination – with the help of a mathematical abstract view, Julius Sumner Miller’s exciting science demonstrations … I felt I should continue this stream of thoughts by adding some observations on the pursuit of science. (These are my compilations from the wonderful book “Truth and Beauty” by Professor S. Chandrashekhar, Penguin Books Ltd (1991) – don’t miss to read this book if you happen to come across). I am aware that I am not offering here any concrete thinking on the “pursuit of science” -- but surely it helps to put things in their places, and it invites deeper thinking on this issue.
“The pursuit of science: its motivations” is a difficult topic because of the variety and the range of the motives of the individual scientists; they are as varied as the tastes, the temperaments, and the attitudes of the scientists themselves. Besides, their motivations are subject to substantial changes during the life-times of the scientists. Indeed it is difficult to discern a common denominator! We may consider some examples to get some better ideas on this. Let us think of Albert Michelson: His main preoccupation throughout his life was to measure the velocity of light with increasing precision. His interest came about almost by accident, when the commander of the United states Naval Academy asked him – he was then an instructor at the Academy – to prepare some lecture demonstrations of the velocity of light. That was in 1878 and it had led to Michelson’s first determination of the velocity of light in 1880. On 7th May 1931, i.e., fifty years later and two days before he died he dictated the opening sentences of a paper, posthumously published, which gave the results of his last measurement! Michelson’s efforts resulted in an improvement in our knowledge of the velocity of light from one part in 3,000 to 1 part in 30,000 – i.e., by a factor of 10. But by 1973, the accuracy had been improved to 1 part in 100000000000 -- a measurement that made obsolete, beforehand, all earlier measurements! Were Michelson’s efforts over fifty years in vain? Leaving that question aside, one must record that, during his long career, Michelson made great discoveries derived from his delight in “light waves and their uses”. Thus, his development of interferometry, leading to the first direct determination of the diameter of a star, is breathtaking. And who does not know the Michelson-Morley experiment, which -- through Einstein’s formulation of the special and the general theory of relativity -- changes irrevocably our formulation of the nature of space and time? It is a curious fact that Michelson himself was never happy with the outcome of his experiment!! Indeed, it is recorded that when Einstein visited Michelson in April 1931, Mrs. Michelson felt it necessary to warn Einstein in a whisper when he arrived: “Please don’t get him started on the subject of the ether”!
When Michelson was asked towards the end of his life, why he had devoted such a large fraction of the time to the measurement of the velocity of light, he is said to have replied “It was so much of fun”! There is no denying that “fun” does play a role in the pursuit of science. What are the other factors? Difficult to say! I leave it open to your own jurisdiction now.
“The pursuit of science: its motivations” is a difficult topic because of the variety and the range of the motives of the individual scientists; they are as varied as the tastes, the temperaments, and the attitudes of the scientists themselves. Besides, their motivations are subject to substantial changes during the life-times of the scientists. Indeed it is difficult to discern a common denominator! We may consider some examples to get some better ideas on this. Let us think of Albert Michelson: His main preoccupation throughout his life was to measure the velocity of light with increasing precision. His interest came about almost by accident, when the commander of the United states Naval Academy asked him – he was then an instructor at the Academy – to prepare some lecture demonstrations of the velocity of light. That was in 1878 and it had led to Michelson’s first determination of the velocity of light in 1880. On 7th May 1931, i.e., fifty years later and two days before he died he dictated the opening sentences of a paper, posthumously published, which gave the results of his last measurement! Michelson’s efforts resulted in an improvement in our knowledge of the velocity of light from one part in 3,000 to 1 part in 30,000 – i.e., by a factor of 10. But by 1973, the accuracy had been improved to 1 part in 100000000000 -- a measurement that made obsolete, beforehand, all earlier measurements! Were Michelson’s efforts over fifty years in vain? Leaving that question aside, one must record that, during his long career, Michelson made great discoveries derived from his delight in “light waves and their uses”. Thus, his development of interferometry, leading to the first direct determination of the diameter of a star, is breathtaking. And who does not know the Michelson-Morley experiment, which -- through Einstein’s formulation of the special and the general theory of relativity -- changes irrevocably our formulation of the nature of space and time? It is a curious fact that Michelson himself was never happy with the outcome of his experiment!! Indeed, it is recorded that when Einstein visited Michelson in April 1931, Mrs. Michelson felt it necessary to warn Einstein in a whisper when he arrived: “Please don’t get him started on the subject of the ether”!
When Michelson was asked towards the end of his life, why he had devoted such a large fraction of the time to the measurement of the velocity of light, he is said to have replied “It was so much of fun”! There is no denying that “fun” does play a role in the pursuit of science. What are the other factors? Difficult to say! I leave it open to your own jurisdiction now.
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