Exploring the Electric Activity of Inert Gases in the Atmosphere

[Gfoxboy]

I just recently saw a video in Physics class about Einstein's thought experiment that led to his discovery of Special Relativity. I was just curious how he knew at that time that light always moves at c even when the observer of the light is moving. I know that is the most important part of SR and I'm sure it's true, I was just curious if someone had discovered that previous to Einstein's thought experiment with the clock and the tram.

 

[Alkatran]

I believe it was the Michelson-Morley experiment which was the first to notice that they couldn't measure light at any other speed than c.

The lorentz contractions were all discovered before Einstein, he only figured out WHY it was working like that. (We're skewed through time)

Of course, that's a very, very big "only"

 

[Nenad]

I believe it was the Michelson-Morley experiment which was the first to notice that they couldn't measure light at any other speed than c.

this only proved that light does not propagate as a wave, and there is no magical 'ether' in the universe in which light travels through.

The lorentz contractions were all discovered before Einstein, he only figured out WHY it was working like that. (We're skewed through time)

The lorents contractions were widely used by Pointclare (a french Mathematician) but they had no idea about the implications of physics. They never had the slightest thought.
What helped einstein prove his theory was simoutinaety, and the fact that two events that happen at the exact same time, can be seen as happening at different times by an observer in another fame of reference.

 

[Alkatran]

this only proved that light does not propagate as a wave, and there is no magical 'ether' in the universe in which light travels through.

But light can be seen as a wave in certain circumstances, especially when you're talking about interference.

The fact that light moves at c would be the disproving of the ether.

 

[Nenad]

But light can be seen as a wave in certain circumstances, especially when you're talking about interference.

The fact that light moves at c would be the disproving of the ether.

Light is onlt thought of as a wave in a probability sence, not in a mechanical sence. It is never thought of as an actual wave propagating though ppace.

 

[russ_watters]

Light is onlt thought of as a wave in a probability sence, not in a mechanical sence. It is never thought of as an actual wave propagating though ppace.

Of course it is - interference is one example, but there are plenty of others where light does act like a wave: radio communications, microwave ovens, lasers, etc.

Whether light is a wave or a particle depends on whether you need it to be a wave or a particle for certain observations.

If you're talking specifically about the aether, the fact that there is no aether does not mean that light can't still be a wave.

 

[pervect]

I just recently saw a video in Physics class about Einstein's thought experiment that led to his discovery of Special Relativity. I was just curious how he knew at that time that light always moves at c even when the observer of the light is moving. I know that is the most important part of SR and I'm sure it's true, I was just curious if someone had discovered that previous to Einstein's thought experiment with the clock and the tram.

AFAIK, Einstein had two main clues that when combined together led him to the conclusion that light must always travel at 'x'.

These were Maxwell's equations, and the Micehlson-Morley experiment.

Maxwell's equations gave a result of the speed of light of 1/sqrt(uo*E0). It would be possible, of course, for these constants to vary with velocity, to make the speed of light vary with velocity. But the Michelson-Morley experiment showed that the speed of light didn't vary with the changes in velocity of the Earth orbiting the sun.

Einstein thought a lot about various alternatives, and decided that the simplest one which matched experimental results was that the speed of light was constant to all observers.

 

[Alkatran]

Of course it is - interference is one example, but there are plenty of others where light does act like a wave: radio communications, microwave ovens, lasers, etc.

Whether light is a wave or a particle depends on whether you need it to be a wave or a particle for certain observations.

If you're talking specifically about the aether, the fact that there is no aether does not mean that light can't still be a wave.

Why are we arguing over what we agree on?

 

[Gfoxboy]

Thanks guys.

 

[davidhart890]

Hi, I just finished reading the special Einstein issue of Discover (of which Dr Michio Kaku article 'Einstein [in a nutshell]' led me (ultimately) to this forum...

I thought I understood and now I'm sure I don't.
If I sat on a particle of light leaving point x at time y and 'you' did exactly the same (in a parallel direction) would I not view 'you' as stationary? the reading suggests different - any other answer other than yes is going to be really hard to swallow.
If you can help me understand this, I would be most grateful

regards,
David Hart

 

[pervect]

If I sat on a particle of light leaving point x at time y and 'you' did exactly the same (in a parallel direction) would I not view 'you' as stationary? the reading suggests different - any other answer other than yes is going to be really hard to swallow.

Well, the very short answer is that you can't sit on a particle of light. The light, being massless, can move at 'c'. You, having mass, can't move that fast. Trying to say you can is like dividing by zero in mathematics - it yields nonsensical results. In fact, if you study the Lorentz transformations, you'll see that moving at 'c' does involve dividing by zero.

 

[JasonRox]

He didn't say physically sit on it!

He just indirectly said visualize yourself as a particle of light. If you can visualize yourself sleeping with Britney Spears when that's impossible, why not visualize yourself as a photon hitting Britney Spears.

Note: I don't have a thing for Spears.

 

[pervect]

Well, if you visualize that 2+2=5, you can conclude, quite logically, that you are the King of England. (See the derivation by the famous mathemetician, Charles Dogson, aka Lewis Carroll).

The point here is that one has to be careful about making impossible assumptions - given one false statement, one can logically prove anything. Moving at 'c' as a material body is one of those impossible assumptions that one should avoid.

ps: It doesn't violate any laws of physics to sleep with Britney Spears. Why, if you won a celebrity date with her, then there was a power blackout while you were out on the date, and then you both got stuck in an elevator alone for 12 hours, you might both get tired and go to sleep. I wouldn't think you'd have much luck having sex with her, though.

 

[robert Ihnot]

AFAIK Einstein had two main clues that when combined together led him to the conclusion that light must always travel at 'x'.
These were Maxwell's equations, and the Micehlson-Morley experiment.

While Einstein clearly gave credit to Maxwell, there is doubt that Einstein was influenced by the M-M experment, even though he wrote in his 1905 paper, "Together with the unsuccessful attempts to discover any motion of the Earth relative to the 'light medium..." This seems to refer to Stellar aberration and Fizeau's experiment on the speed of light in moving water.

I base this on "Understanding Relativity," by Leo Sartori p52, where it is stated that in an interview in 1950, Einstein told Robert Shankland that he became aware of the M-M experiment only after 1905 and Einstein added,

"Otherwise I would have have mentioned it in my paper."

 

[humanino]

could not help

The lorents contractions were widely used by Pointclare (a french Mathematician) but they had no idea about the implications of physics. They never had the slightest thought.

Because I am a very proud and arrogant french guy, I would like to point that Poincare is among the most important mathematicians of the beggining of the century, and was not so far behind Einstein, probably closer than Hilbert for instance :tongue2:

Poincare especially was the first to backup Einstein in France, and maybe also in Europe. Since physicists could not yet undestand Einstein's theory, and it looked to much like philosophy to them, horrible statements have been made. When Einstein was invited to the french Academie, a well-known scientist declared "Who needs the theory of this jewish guy who, thinking he is prosecuted, prides himself with an ununderstanble theory, invented by others anyway"

 

[ШЇSЭЯ]

does light always travel at the same speed no matter where it comes from??
just curious, I am new to this i need to read up, a lot
and where can i read that article by michio "Einstien [in a nutshell]"

 

[HallsofIvy]

Yes, that's the whole point of special relativity. In "classical mechanics", if you were standing by the side of a road, I was in a truck traveling at 40 mph and throw you a ball at (relative to me) 30 mph, the ball would be traveling at 70 mph relative to you.

Experimental evidence shows that that is not true for light. If a I am moving toward you at 1/2 the speed of light (1/2 c) and shine a light at you (speed, relative to me c), you would see the light coming toward you at c, not 3/2 c.

 

[airlinemusic]

AFAIK, Einstein had two main clues that when combined together led him to the conclusion that light must always travel at 'x'.

These were Maxwell's equations, and the Micehlson-Morley experiment.

Maxwell's equations gave a result of the speed of light of 1/sqrt(uo*E0). It would be possible, of course, for these constants to vary with velocity, to make the speed of light vary with velocity. But the Michelson-Morley experiment showed that the speed of light didn't vary with the changes in velocity of the Earth orbiting the sun.

Einstein thought a lot about various alternatives, and decided that the simplest one which matched experimental results was that the speed of light was constant to all observers.

Thats what I was looking for, eo and uo came from electrostatic, E, and
electromagnetic, H, Force equations.

Maxwell's equations dealing with dE/dt and dH/dt ended up with those
factors that each or both factored together can be equated to c.

In grad school Optics class, I recall that light comes from electron
energy level changes but when press on how it bounces off walls and
objects he gave something like its just re emitted or bounce without
little decay and did not go into too much detail.

After all it was the first chapter but I recall that more than what was
in the rest of the book.

 

[airlinemusic]

Because I am a very proud and arrogant french guy, I would like to point that Poincare is among the most important mathematicians of the beggining of the century, and was not so far behind Einstein, probably closer than Hilbert for instance :tongue2:

Poincare especially was the first to backup Einstein in France, and maybe also in Europe. Since physicists could not yet undestand Einstein's theory, and it looked to much like philosophy to them, horrible statements have been made. When Einstein was invited to the french Academie, a well-known scientist declared "Who needs the theory of this jewish guy who, thinking he is prosecuted, prides himself with an ununderstanble theory, invented by others anyway"

After all that I wonder if Einstein ever settled for a final understanding
of his own ideas, he was always involved in Unified Field Theory that
brings us String Theory as a solution. Given the varoius ways to
solve equations it almost sounds like a Fourier series solution which
he could have applied long ago.

Ha, another French solution. Does the solution mean radiation is present
as strings or rings.

 

[bernhard.rothenstein]

Einstein's thought experiment?

I just recently saw a video in Physics class about Einstein's thought experiment that led to his discovery of Special Relativity. I was just curious how he knew at that time that light always moves at c even when the observer of the light is moving. I know that is the most important part of SR and I'm sure it's true, I was just curious if someone had discovered that previous to Einstein's thought experiment with the clock and the tram.

Please have a criical look at
arXiv.org > physics > physics/0510178

 

[rbj]

I just recently saw a video in Physics class about Einstein's thought experiment that led to his discovery of Special Relativity. I was just curious how he knew at that time that light always moves at c even when the observer of the light is moving. I know that is the most important part of SR and I'm sure it's true, I was just curious if someone had discovered that previous to Einstein's thought experiment with the clock and the tram.

please take a look at the post i just did at the Relativity and light thread in this forum. i think that it spells out, as a thought experiment, what Einstein was thinking about. it wasn't merely the negative result of the Michaelson-Morley experiment. it's because Einstein had the insight to insist that for two different observers, both inertial, unaccelerated - moving at a constant velocity but possibly moving relative to each other, both observers have equal claim to being "stationary" (and it's the other guy that's "moving") and that the laws of physics (namely Maxwell's Equations) both qualitatively and quantitatively apply exactly the same to both observers. that means both observers have the same permittivity of free space ($\epsilon_0$) and permeability of free space ($\mu_0$) and then, when they both solve Maxwell's equations, must get the same speed of light. if the speed of light was different for one compared to the other, then that person has, at least quantitatively, a different set of physical law than the other.

 

[bernhard.rothenstein]

please take a look at the post i just did at the Relativity and light thread in this forum. i think that it spells out, as a thought experiment, what Einstein was thinking about. it wasn't merely the negative result of the Michaelson-Morley experiment. it's because Einstein had the insight to insist that for two different observers, both inertial, unaccelerated - moving at a constant velocity but possibly moving relative to each other, both observers have equal claim to being "stationary" (and it's the other guy that's "moving") and that the laws of physics (namely Maxwell's Equations) both qualitatively and quantitatively apply exactly the same to both observers. that means both observers have the same permittivity of free space ($\epsilon_0$) and permeability of free space ($\mu_0$) and then, when they both solve Maxwell's equations, must get the same speed of light. if the speed of light was different for one compared to the other, then that person has, at least quantitatively, a different set of physical law than the other.

how could I see your relatiity and light?. i like solutions that result from the first postulate. I have seen an answer to the question based on the relative motion of a coil and a permanent magnet

 

[turbo]

this only proved that light does not propagate as a wave, and there is no magical 'ether' in the universe in which light travels through.

To the contrary, the fact that light seems to propagate at c through a vacuum can be interpreted as though the vacuum has a refractive index and a maximum speed at which light can propagate through it. Every material through which light can propagate has a "speed limit" of this type. If you will Google on "Klaus Scharnhorst", you will find numerous references to the Scharnhorst effect, in which the speed of light through a vacuum is expected to be higher if you can physically exclude some wavelengths of vacuum fluctuations, as in the gap between the conducting plates of a Casimir device. If he is right, the quantum vacuum field is the ether.

http://en.wikipedia.org/wiki/Scharnhorst_effect

 

[rbj]

how could I see your relatiity and light?. i like solutions that result from the first postulate. I have seen an answer to the question based on the relative motion of a coil and a permanent magnet

i'm not sure what it is that you're asking Bernhard?

 

[bernhard.rothenstein]

light and relativity

i'm not sure what it is that you're asking Bernhard?

My question is how could I see your "Light and relativity" post.

 

[pess5]

I just recently saw a video in Physics class about Einstein's thought experiment that led to his discovery of Special Relativity. I was just curious how he knew at that time that light always moves at c even when the observer of the light is moving. I know that is the most important part of SR and I'm sure it's true, I was just curious if someone had discovered that previous to Einstein's thought experiment with the clock and the tram.

Pervect got it right. Einstein simply accepted Maxwell's equations that the speed of light is c=1/sqrt(uo*E0) in vacuum, which inferred that material motion has no effect on light's speed.

Einstein stated he was unaware of Michelson & Morley's experiment whereby they measured the speed of light using a device they built called an interferometer. Einstein was convinced light's speed was invariant c from Maxwell's theory alone.

pess

 

[airlinemusic]

Voltage and frequency response

permittivity of free space (uo) and permeability of free space (eo)

Is there any evidence that either can be a function of voltage (v) and
frequency (f) such that u0(v,f) and eo(v,f) can be examined.

 

[Chris Hillman]

"History" a la internet?

Oh dear, oh dear:

The lorents contractions were widely used by Pointclare (a french Mathematician) but they had no idea about the implications of physics. They never had the slightest thought.

Nenad, you managed to misspell the names of both people you mentioned in the first sentence. More importantly, your comments exhibit considerable ignorance of what is known about the contributions of Poincare and Lorentz to the rise of relativistic physics. A good place to start would be Einstein's Clocks, Poincare's maps, by Peter Galison, Norton, 2003.

 

[airlinemusic]

Is there any evidence that either can be a function of voltage (v) and
frequency (f) such that u0(v,f) and eo(v,f) can be examined.

Any one have data of UV from coil sparks and properties of 'dark matter' in the air
or even liquid air.


http://chemeducator.org/sbibs/s0009006/spapers/960378gk.htm

The Discovery of Argon

Until the last decade of the 19th century, chemists thought that the air had been so thoroughly studied that no one dreamed that it could possibly contain hitherto unknown elements [15]. However, in 1785 English chemist Henry Cavendish (1731–1810) noticed that when he repeatedly passed an electric spark through a mixture of oxygen and air in the presence of alkali (“soap lees”) part of the “phlogisticated air” (nitrogen) had failed to combine with the “dephlogisticated air” (oxygen) [16]. According to Cavendish, this residue was

certainly not more than 1/120 of the bulk of the phlogisticated air [nitrogen] let up into the tube; so that if there is any part of the phlogisticated air [nitrogen] of our atmosphere which differs from the rest and cannot be reduced to nitrous acid, we may safely conclude that it is not more than 1/120 part of the whole [17, 18].

Although Cavendish suggested that, in addition to nitrogen, oxygen, carbon dioxide, and water vapor, air might contain another unreactive, colorless, odorless, insoluble gas, his experimental results were forgotten by most chemists. More than a century later—in the course of an investigation of the densities of hydrogen and oxygen to learn if their ratio confirms Prout’s hypothesis (He found their ratio to be 1:15.882 [19].)—Lord Rayleigh (John William Strutt) (1842–1919) found that the density of nitrogen prepared from ammonia (NH3) was less than that of nitrogen prepared from air. In a letter of September 7, 1892 to the journal Nature he reported his results and asked readers to suggest an explanation for the discrepancy, which was beyond experimental error, but no suggestions were received [20]. At a meeting of the Royal Society on April 19, 1894 he suggested that chemically prepared nitrogen might be contaminated with a less dense gas.

Ramsay then asked Rayleigh for permission to experiment with atmospheric nitrogen [15, 17, 21]. In his Nobel address, he stated:

In my copy of Cavendish’s life, published by the Cavendish Society in 1849 [22], opposite his statement that on passing electric sparks through a mixture of nitrogen with an excess of nitrogen,…I find that I had written the words “look into this.” It must have been the latent memory of this circumstance which led me, in 1894, to suggest to Lord Rayleigh a reason for the high density which he had found for “atmospheric nitrogen” [2].

Contrary to Rayleigh’s supposition, Ramsay believed that atmospheric nitrogen might contain a denser gas. In large-scale experiments he passed atmospheric nitrogen repeatedly over hot magnesium, which reacted to form solid magnesium nitride (Mg3N2) and left behind a small amount (about 1/80) of an unreactive gas. When he analyzed the gas spectroscopically, he observed, in addition to the lines of nitrogen, lines of a hitherto unknown gas. Sir William Crookes (1832–1919) later studied its spectrum and observed nearly 200 lines [23]. Rayleigh also repeated Cavendish’s experiments and confirmed the presence of an unknown gas (1/107 of the original volume).

Ramsay and Rayleigh began to work together and exchanged letters almost every day. On May 24, 1894 Ramsay wrote, “Has it occurred to you that there is room for gaseous elements at the end of the first column of the periodic table?” On August 4 he wrote to Rayleigh that he had isolated the gas, and on August 6 Rayleigh replied that he too had obtained it “in miserably small quantities,” and he suggested that they jointly announce their discovery [15, 24]. On August 7 Ramsay agreed, and on August 13, 1894 the pair announced their discovery to the British Association at Oxford of a new element in the atmosphere—the first inert gas—which at the suggestion of the chairman, H. G. Madan, they called “argon” from the Greek, meaning “the lazy one,” because of its unreactivity [21, 25, 26]. Ramsay made a formal report of his and Rayleigh’s results before an audience of at least 800 persons in a lecture at the University of London on January 31, 1895 [24]. Ramsay suggested that it be placed in a new group of zerovalent elements in the periodic table between chlorine and potassium [27]. The collaboration between Ramsay and Rayleigh was apparently an ideal one, for according to Ramsay’s assistant Morris W. Travers (1872–1961), in all the correspondence between the two “there is no indication…of suspicion or sense of injustice on either side” [21].

The Discovery of the Other Inert Gases

During the next three years four other inert gases were discovered. In 1868 in India French astronomer Pierre-Jules-César Janssen (1824–1907) observed a total eclipse of the sun and made the first spectroscopic study of its chromosphere [28]. English astronomer Sir Norman Lockyer (1836–1920) found that a new yellow spectral line (D3) noted by Janssen did not belong to any known element but to a hypothetical new element, which he named “helium” (Greek, sun) [29]. (The suffix “ium,” characteristic of the names of metals, apparently indicated that Lockyer thought that the element was a metal.) For a quarter of a century scientists believed that although it might possibly exist on the sun, it had never been found on the earth. In fact, most spectroscopists doubted its existence, and some even ridiculed it [29].

In 1888–1890 American chemist William F. Hillebrand (1853–1925) treated the mineral uraninite with acid and noted the evolution of a gas that he thought was nitrogen [30]. Ramsay disagreed with Hillebrand’s results and repeated the experiment with a similar uranium mineral, cleveite [31, 32]. He obtained nitrogen but also argon and another gas with different spectral lines. He sent samples of the unknown gas to Sir Norman Lockyer and Sir William Crookes. By March 1895 the new gas was shown to be identical with Lockyer’s solar element—helium [27, 33]. At about the same time Swedish chemist Per Theodor Cleve (1840–1905) and his student Nils Abraham Langlet (1868–1936), independently of Ramsay, also discovered helium in cleveite. Ramsay had announced his discovery earlier, but the Swedes’ gas was purer than Ramsay’s, and they obtained a much better value for its atomic weight [34].

Because the atomic weights of helium and argon were found to be ca. 4 and 40, respectively, Ramsay believed that they might belong to a new group of the periodic system and consequently an intermediate member of the group with an atomic weight of ca. 20 might exist [35]. After abandoning their attempts to discover new gases by heating rare minerals, Ramsay and Travers decided to fractionate liquid air. They removed oxygen and nitrogen by reaction with red-hot copper and magnesium, respectively [36, 37]. On May 31, 1898 they examined the spectra of the inert residual gas and observed a bright yellow line with a greener tint than that of helium and a brilliant green line that did not coincide with any line of hydrogen, helium, argon, or mercury [21, pp 90–91]. They announced their discovery on June 6, 1898 and named the new gas krypton (Greek, hidden) [17, pp 251–255].

However, krypton was not the element intermediate between helium and argon that Ramsay and Travers were seeking but a denser one. Therefore, they continued their search for more than two years for the lighter gas by liquefying and solidifying their argon by surrounding three liters of it with liquid air boiling under reduced pressure, allowing the argon to volatilize, and collecting the more volatile portion, which distilled off first. According to Ramsay’s laboratory notebook, the lightest fraction

gave magnificent spectrum with many lines in red, a number of faint green, and some in violet. The yellow line is fairly bright, and persists at very high vacuum, even phosphorescence [21, pp 95–97].

Willie, Ramsay’s 13-year-old son, asked his father, “What are you going to call the new gas? I should like to call it novum.” (Apparently, at that time, teenagers were fluent in Latin. What a contrast with today!) Ramsay agreed but chose a similar, but better sounding name “neon” (Greek, new) for the gas discovered in June 1898.

By using a new liquid air machine provided by British chemist and industrialist Ludwig Mond (1839–1909), Ramsay and Travers were able to prepare larger amounts of neon and krypton. By repeated fractionation of krypton, on July 12, 1898 they isolated an even heavier inert gas that exhibited a bright blue glow in a vacuum tube. They named it xenon (Greek, stranger) [17, pp 251–255].

The last inert gas to be discovered was first called radium emanation, emanon (no name spelled backwards!), or niton. Pierre (1859–1906) and Marie Curie (1867–1934) noted that when air contacts radium compounds, it becomes radioactive. In 1900 Friedrich Ernst Dorn, Professor of Physics at the Universität Halle, explained this fact by showing that one of the disintegration products of radium was an inert gas, now known as radon [38–40]. In 1903, together with future (1921) Nobel chemistry laureate Frederick Soddy (1877–1956), Ramsay detected the presence of helium in the emanations of radium. In 1910 Ramsay and Robert Whytlaw Gray (1877–1958) determined its density and showed that it is the densest gas known [41].

We now fast-forward more than a half century. As chemical educators, we visualize ourselves as open-minded scientists uninfluenced by authority, who pride ourselves on viewing our scientific beliefs not as absolute truths but as tentative hypotheses that we are prepared to modify or abandon in the light of new discoveries. However, in July 1962, while attending a conference on Advances in the Chemistry of Coordination Compounds held at Ohio State University in Columbus, my open-mindedness was put to the test—and I flunked! [42]. Someone interrupted one of the lectures and announced that Neil Bartlett, a young (born 1932) and comparatively unknown lecturer at the University of British Columbia at Vancouver, had prepared a compound of an inert gas—xenon hexafluoroplatinate(V), XePtF6 [43, 44].

For chemists of my generation the inertness of the inert gases was a watchword that we diligently and regularly taught to students in our introductory chemistry courses. A common witticism among us was that a book on The Chemistry of the Inert Gases would be a volume with blank pages. Therefore, faced with the news that one of chemistry’s most cherished assumptions had been broken, I chose to assume that the announcement was a joke. After all, chemical educators, especially when away from their academic home grounds, have been known to delight in foisting all sorts of pranks on their unsuspecting colleagues. But the joke was on me when I found a detailed report about Bartlett’s discovery in Chemical & Engineering News on my return from the conference. This discovery forced every teacher or textbook author of introductory chemistry to revise his or her previous treatment of atomic structure—a humbling experience that shows how far short we fall from our ideals.

In 1962 several inert gas fluorides were isolated [45–48], and soon many other inert gas compounds were prepared. Since then, inert gases are known as “noble gases,” and many books, numerous reviews, a book-length bibliography, and an entire volume of Gmelins Handbuch der anorganischen Chemie have been devoted to the chemistry of a group of elements that not too long ago were universally thought to have no chemistry at all. Surely, a cautionary tale for all of us!

Inert but still electrically active in some way and all in the air.