studiot

Isn't that exactly what I said?

Easy there, that statement needs backup. Speed invariance is a (very reasonable) assumption underlying Einstinian relativity, it is not, however a postulate. The point is that we accept the einstinian explanation over other conceivable ones as it best fits observational data. But note that we have only done this after exhaustive experimentation. For instance many structures for the aether (as a transmission mediim for light) have been proposed and much effort has been put into finding it. No experiment has ever demonstrated its existence. So we conclude that light generates its own medium as it goes along, there is no aether. So we cannot attribute the observed effects to the medium, they must be part of time and space. However that does not make lightspeed invariant. It is possible to produce a model whereby lightspeed varies just enough dring its journey from source to observer to make it the same for all observers. Again we reject this model after experimentation. Constant lightspeed is equivalent to asserting the homogeny and isotropy of space(time) which we consider a desirable property. So there are deep and fundamantal reasons for choosing the conventional explanatory path, it is not just a whim or response to a single observation or experience.

Games with mirrors are not the only way to come at special relativity, they are really just an attempt to offer a simple example. The mathematical theory contains no mirrors at all. Secondly you miss the key point of the second postulate. For all waves, not just light, the speed of the wave is independent of the speed of the source, relative to the medium. The speed is determined by the characteristics of the medium of propagation alone. The key point of the second postulate that makes light different from other waves is that for all other waves the observed speed depends upon the speed of the observer relative to the medium. The second postulate states that the speed of light is independent of the speed of the observer as well as the speed of the source and hence is the same for all observers. Another corollary is that the speed of light is independent of the relative speed between source and observer. It is this last version that is used to deduce the effect on time and space.

The events of the flooding of the Euxine flooding is the subject of several hypotheses, including the one in the book I mentioned, although I think the figure of 1000' is exaggerated. https://www.google.co.uk/search?hl=en-GB&source=hp&biw=&bih=&q=flooding+the+Euxine&gbv=2&oq=flooding+the+Euxine&gs_l=heirloom-hp.3...1281.5687.0.6078.19.12.0.7.7.0.282.1594.0j10j1.11.0....0...1ac.1.34.heirloom-hp..6.13.1719.X1jsaRYzXFA

Y?

If the conditions of the question state that the answer is independent of the mass of ice than that is (one of) the conditions of the question. Such a condition leads to certain inescapable conclusions as we have been discussing.

I see not evidence of a crater within your boundary or even that the rocks are from the same geological eras. Have you compared your map with geological maps of the area for example, Are the rocks within your boundary the sort you expect to see within an old volacanic crater?

You should read the book referred to in post#1 here. http://www.scienceforums.net/topic/91566-doggerland-and-sea-levels-in-the-last-15000-years/ The formation of the Baltic is discussed in that book, along with the history of the North Sea and many other parts of the world drowned by rising sea levels.

Hello, Nicholas, nice to see you are still with us. I answered as I did in case this actually was a homework question. Since the OP appears no longer interested it seems reasonable to me to discuss it in more detail. The problem appears ill posed as described, but the OP did make an effort to point out that the mass of ice is irrelevant. So in theory the result should be true for 0.1 grammes 1 gramme, 10 grammes, 100 grammes 1,000 grammes or 10,000 grammes of ice. You are, however correct to observe that no amount of ice can ever freeze the water and there is a minimum amount of ice below which the ice will all melt without reducing the water to 0oC. Can you see why this is? It may be that this was the intention of the question, however the OP does say that the ice melts completely.

Is nu not the refractive index and mu the relative permittivity of the medium of propagation?

I note several research articles for analysis of the Donnan Equation with divalent ions, some using numerical methods to solve the equations. Presumabably you need to go back to first principles to derive the relationships.

Very good (teaching) points Sensei. +1

Since you have posted this in homework help I assume it is not a trick question from somewhere, but real coursework designed to make you think. Well done for detailing your thoughts, but you haven't actually stated the question as posed. So I am going to make some assumptions. what will the final temperature of the water be? The ice melts because heat is transferred from the water to the ice. So what are the conditions required for heat transfer to take place? Ans: There has to be a temperature difference between the water and the ice. Since the ice starts at 0oC (Assumption number 1 ) and the water starts at 10oC heat is transferred from the wate to the ice, which cools the water and melts the ice. The cooler water is now at a temperature lower than 10oC. You are told that the mass of ice is irrelevant but you are not told that the glass is insulated (Assumption number 2) Assumption number 3 is that the glass of water is initially in equilibrium with its surroundings. Since the water is now cooler than its surroundings heat is transferred from the surroundings to the water. So what do you now think is the final temeperature of the water ?

Hey, Mig be careful with my cup!

Then you need to be more specific. Are you defining 'natural' as inanimate or non human or what?

You didn't say but I assume the combustion takes place in an adequate supply of oxygen. You need to write balanced equations for the combustion of cocaine and sugar and combine the two equations into a single one, using the proportion of cocaine = X and the proportion of sugar = (1-X) Have you done this?

You keep claiming there are no 'natural' (ie totally independent of humans) processes that can lead to the formation of a (ceramic) cup. I proved this totally wrong in my post#22 where I demonstrated one such sequence.

You should research papers by the following geologists. Jean-Philippe Avouac (Cambridge) https://www.google.co.uk/search?q=jean-philippe+avouac+cambridge&hl=en-GB&biw=&bih=&gbv=2&oq=jean-philippe+avouac+&gs_l=heirloom-serp.1.0.0l3j0i22i30.3313.4032.0.6172.5.5.0.0.0.0.78.390.5.5.0....0...1ac.1.34.heirloom-serp..0.5.390.2xuuHcufdEM Philip England (Oxford) https://www.google.co.uk/search?q=philip+england+geology&hl=en-GB&biw=&bih=&gbv=2&oq=philip+england&gs_l=heirloom-serp.1.2.0l2j0i22i30l8.75704.80829.0.85641.14.13.0.1.1.0.265.1532.4j8j1.13.0....0...1ac.1.34.heirloom-serp..0.14.1563.HzMkO7zvC5s Who are (the) leading researchers in this field. The BBC produced a program about this with lots of computer simulations. Unfortunately I don't think it is availble in India, though it may be on youtube. Look for Earth Story (episode 4 I think) There is also a book and a DVD made by the BBC for this. The BBC material will be a little less technical than the boffins.

I have been unable to open yopur link on older systems and newer ones reject download of your the pdf as unsafe. However I can read it online and I see that it contains some glaring chronological errors. How can one eruption simultaneously wipe out the dinosaurs and bury ancient Indian civilisations? These events were separated over (edit 250 million) millions of years in time. You are however correct that there is much evidence that the fomation of the Himalaya and Tibetan Plateau is much more complicated than a simple collision between plates and that vulcanism from reheated rocks produced lava eruptions. Furhter the Tibetan Plateau appears to have originated as the ocean floor of the Tethys ocean and been uplifted. The current theory is that the mountain chain root was so deep it melted and separated downwards, allowing the upper mountain body to bob up.

Thanks for the advice and link, Endy. +1 The setting was indeed Quick access. However changing this did not properly cure it. For instance on the desktop there are 3 shortcuts, but it persistently only reports one of them.

Since my windows XP is getting increasingly difficult to use I thought I would try 10. Great for the first week then File explorer 'lost' several important folders I had recently created. Instead it concentrated on showing me all sorts of rubbish I didn't ask for and don't want. Surely the point of a file / folder listing program is to list files?

Are you sure? Look at the 'spectrum' of the low pressure sodium lamp here and compare with other lamps. http://www.lamptech.co.uk/Documents/SO%20Spectral.htm If you filter that line out you will have nothing left.

Sodium bulbs produce monochromatic light. (Do you understand this ?) Actually I think they have two very closely spaced lines.

I don't understand the question. Is this about money or modern ways to create filters? Before modern coatings on glass, filters were made by dissolving suitable absobers in gelatin and letting them set. This was much cheaper for amateurs. Perhaps you could reasearch this. What light do you want to filter out? https://www.google.co.uk/search?hl=en-GB&source=hp&biw=&bih=&q=gel+filters&gbv=2&oq=gel+filters&gs_l=heirloom-hp.1.0.0l6j0i22i30l4.844.4032.0.12282.11.11.0.0.0.0.235.1502.0j10j1.11.0....0...1ac.1.34.heirloom-hp..0.11.1502.Rr4PoIZwVVc

Somewhat dificult to comment without knowing the %s involved.