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Waves
Feb 10, 2011 15:53:22 GMT 1
Post by jonjel on Feb 10, 2011 15:53:22 GMT 1
Helen, I expressed myself badly. He had several waves made, each out of glass with a different refractive index. As for the coffee, maybe he did not drink black coffee and his view was obscured by the milk
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Waves
Feb 10, 2011 15:56:08 GMT 1
Post by helen on Feb 10, 2011 15:56:08 GMT 1
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Waves
Feb 10, 2011 16:00:11 GMT 1
Post by jonjel on Feb 10, 2011 16:00:11 GMT 1
Brilliant Helen, and dwell for one moment on all the energy stored in that one cloud.
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Waves
Feb 10, 2011 16:14:01 GMT 1
Post by speakertoanimals on Feb 10, 2011 16:14:01 GMT 1
No, I meant the pattern you can see on the top of the coffee! That pointy, cusp-shaped pattern of brighter parts.
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Waves
Feb 10, 2011 16:25:25 GMT 1
Post by jonjel on Feb 10, 2011 16:25:25 GMT 1
STA.
For the sake of science I have just made myself a coffee, and don't see any light interference patterns on the surface, whether I rock the cup about or not.
Nor do I recall seeing it in beer, well, not in the first pint or three...
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Waves
Feb 10, 2011 16:49:13 GMT 1
Post by carnyx on Feb 10, 2011 16:49:13 GMT 1
Jonjel; STA was obviously making a caustic remark.
Re waves maybe you saw a mini-tsuanami, cause by a distant tremor? Years ago, I lived for a while on one of the Frisian islands, and early one morning I went to the beach to see that, in the night, a huge wave had been right up to the sand-dunes and left a four foot high 'cliff'.
I have since then seen the similar phenomenon down at West Wittering last year, on the dunes of Winner Head. Maybe these great waves are not as unusual as all that.
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Waves
Feb 10, 2011 17:02:58 GMT 1
Post by speakertoanimals on Feb 10, 2011 17:02:58 GMT 1
Ah, they're NOT interference patterns! I can't do it with mine at the moment -- take-away cup! you need a proper glazed mug with a reflective inner surface. Then you get the curved side acting like a lens. For water ripples, you get caustics: The basic idea is that the peak of a wave acts as a converging lens, the trough like a diverging one. What we see (either on the bottom of a pool, or on the underside of bridges), is the bright lines. Add two different sinusoidal waves, at an angle to each other, and you get more complicated stuff. Ah! Got it! Nephroid caustic in a cup: en.wikipedia.org/wiki/File:CardioidInCoffeeGlass.jpgAnd more on caustics: en.wikipedia.org/wiki/Caustic_%28optics%29
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Waves
Feb 11, 2011 12:45:39 GMT 1
Post by helen on Feb 11, 2011 12:45:39 GMT 1
Carnyx, why do have to be so provocative and unpleasant to your fellow posters? it does you no favours and doesn't promote further discourse. My students wonder why folks talk to you!
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Waves
Feb 11, 2011 14:07:11 GMT 1
Post by carnyx on Feb 11, 2011 14:07:11 GMT 1
Helen, to help answer you question, you could ask your students to consider this exercise in physics and comprehension, compiled from this very thread!
#############
#24Jonjel - Friend (a physicist) observes patterns at the bottom of the pool; and concludes it is a refractive process.
#26STA -Says about jonjel's friend ( and fellow physicist) .... ' Well, he wasn't very observant then' ...{could this be construed as as a 'scoffing' remark?} ... and then cites reflective patterns from the sides of a cup, which was NOT what the friend had observed at all!
.. but STA goes on yet again to make comment on the effects of convex and concave waves ..which we have already been told was what the physicist friend had concluded, as they are refractive processes)
#30Jonjel - makes a joke about the cup reflections.
#33STA - again mentions reflections rather than refractions, but does not know much about this very well known aspect of the physics of reflection, (or the mathematics of cusps, and their connection with the hot physics topic of catastrophe theory) {is this a bit surprising for a physicist not to know?}
#34Jonjel - tries to repeat STA's observation on reflection from the side of a cup, but fails. {is he teasing STA?}
#35Carnyx,- Gives the name of this phenomenon.. but makes an academic joke of it, as an allusion to STA's asperity in her Post 26 towards a fellow physicist
{would you say the meanings of scoffing, asperity, and caustic go together?}
#36 STA posts .... 13 minutes later! No acknowledgement of STA's academic joke .. But declares these various light patterns are NOT 'interference' .. as nobody has suggested ..
{could this is this non-sequitur be a distraction? }
..... but Caustics! .....
Then, proceed to quote the results of a quick Google search for 'caustics';
################
Now Helen, perhaps you could take your students through this sequence, and answer the questions in {}?
And one last one, what do you students make of STA as a physicist? As a poster?
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Waves
Feb 11, 2011 14:32:40 GMT 1
Post by helen on Feb 11, 2011 14:32:40 GMT 1
What in God's name are you banging on about? Jongel comes over as a nice guy and speakertoanimals as a scientist harrassed by folk like Naymissus and Abacuss who havn't either the wit or wisdom to take on what she says or she is being wound by gits. It's not funny. I would celebrate her fortitude Carnyx, you'd have no fun blowing your weird trumpet without her.
As to the main body of your last post I'll get back later. Have to get back to work.
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Waves
Feb 11, 2011 14:52:10 GMT 1
Post by Progenitor A on Feb 11, 2011 14:52:10 GMT 1
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Waves
Feb 11, 2011 15:31:57 GMT 1
Post by speakertoanimals on Feb 11, 2011 15:31:57 GMT 1
Factual inaccuracies:
I mentioned both reflections andc refractions because in the coffe cup example, it is REFLECTION from the inside of the cup that produces the pattern. Whereas in the swimming pool case, it is refraction. Hence why I mentioned both.
Except they are closely related phenomena, which is why I mentioned the coffe case. Also, people are more likely to havev a coffe cup nearby than a swimming pool, hence I was trying to make it more accessible.
I didn't go into the now slighty cool topic of catastrophe theory. because I thought that using phrases such as 'elliptic umbilic' or hyperbolic umbilic' wouldn't add much to the discussion, and especially when the basic nature of the phenomenon was under discussion.
Just plain wrong . Message by Jonjel:
Which managed to produce a picture of the very phenomenon that I had already introduced!The point being, I knew about it BEFORE I googled, rather than just googling in a vain attempt to find something sexy-sounding on a topic I actually knew nothing about.
Because he bloody WASN'T physicist or not! It was a pattern I'd wondered about as soon as I saw a swimming pool, and wondered about again as soon as I started doing optics at school. I didn't leave it until my honeymoon, I had FAR better things to do, thank you very much..........
I think people would (if they really must), look at what Carnyx has said, and how he can't even get the factual bits right about stuff that is right in fromt of his face! And perhaps ponder what he is more interested in, the phenomena under discussion, or just trying to score some points by having a poke at me. But frankly, people would be better off making a cup of coffee, and trying to see the pretty patterns!
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Waves
Feb 11, 2011 15:34:59 GMT 1
Post by speakertoanimals on Feb 11, 2011 15:34:59 GMT 1
Well, since your link doesn't actually work......................
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Waves
Feb 11, 2011 16:09:21 GMT 1
Post by carnyx on Feb 11, 2011 16:09:21 GMT 1
STA, 'Having a poke' is exactly what you do!
...which is demonstrated on this very thread in post #26, and so is the answer to Helen's #37. And further instances are given by NM that are memorable enough, without requiring links.
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Waves
Feb 11, 2011 16:19:04 GMT 1
Post by abacus9900 on Feb 11, 2011 16:19:04 GMT 1
STA, 'Having a poke' is exactly what you do! ...which is demonstrated on this very thread in post #26, and so is the answer to Helen's #37. And further instances are given by NM that are memorable enough, without requiring links. carnyx, might I suggest that the best way to deal with people like this is to simply ignore them in the future? By responding you just give them oxygen and I have no intention of doing so any longer. I love a good old 'knock about' argument and I have no problem with being told I have no idea about what I am talking about but using personal abuse is unacceptable in my view.
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