Endimion17
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Potassium vapor color
Now this is quite interesting. Found it on an interesting channel, too.
<iframe sandbox width="560" height="315" src="http://www.youtube.com/embed/5hM--wQlOb4" frameborder="0" allowfullscreen></iframe>
As I'm not capable of doing similar experiments at the moment, I urge you to replicate his conditions.
After that, use argon atmosphere and freshly degassed water.
I doubt lithium would show anything because it reacts too slowly so there aren't so many hot metal vapors, but you're welcome to try this on every
alkali metal you have.
This is a peculiar phenomenon I've never seen before, and the references are extremely rare. At first I thought it was a hoax.
I know that there aren't any appreciably visible vapors when potassium is heated in vacuo. A useful mirror is formed and that's it.
So what's the green stuff? Does it have something to do with the water vapor, too, or it's due to the temperature involved? This is a great
opportunity for making genuine experiments, so don't miss it. Just be careful.
No doubt that we'll see more on this in the next few years, courtesy of Internet memetics. 
I'll try to get some decent official info and share it with you in the following days.
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m1tanker78
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Maybe irrelevant but this reminded me of some observations I made a while back with warm sodium oxidizing in air. I never could figure out exactly
what caused a ghostly blue glow around the warm sodium. I tried to reproduce and take some pics and vids but my camera distorted the color to a
red-violet so I never published them.
http://www.sciencemadness.org/talk/viewthread.php?tid=15769#...
As far as the green stuff: my knee-jerk thinking takes me first to the hydride. I've made and seen NaH in pure white, grey, and OD GREEN. I'd need to
double check my notes, though.
Tank
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woelen
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I think that the green is due to peroxide/superoxide formation. Sodium peroxide is yellow, potassium superoxide is orange, but when very finely
divided it is yellow. Potassium also forms blue compounds with oxygen and traces of water. All of these colored compounds are rich in oxygen, the
plain oxides are white.
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Endimion17
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m1tanker78, then that would be a very impure hydride. Alkali metal hydrides don't have colors because their ions aren't capable of producing them.
Regarding your note, glow is emission spectrum, and here we have an absorption spectrum. The thing leeches something green that really resembles
vapor.
woelen, so you think this is an aerosol we see? If someone could make potassium vapor in vacuo, and potassium vapor at 1 atm of argon (difficult to do
because of its high boiling point), and there was no green stuff present, then that would be a pretty conclusive way of proving that the green stuff
is a compound.
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blogfast25
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This guy is largely a bullshitter (at least on this occasion).
For starters, the cesium part of the Brainiac video was 100 % fraudulent, to which they [Brainiac] admitted:
http://www.badscience.net/2006/07/brainiac-fake-experiments-...
When they actually tried with a vial of cesium the reaction was much less strong than expected but with the cameras rolling, budgets in place and
deadlines to be met, they decided to help things along with… a bit of conventional explosive!
If Pompous Git didn't know that then he doesn't know much, as far as I'm concerned...
His experiment to try and eliminate oxygen is far from perfect: decent flushing with oxygen free argon of the whole system is the only way to fully
eliminate the subsequent reaction of the generated hydrogen with oxygen.
Comparing the reactions of the alkali metals with water is difficult to do in an objective way and that’s why there’s a whole mythology about it,
to which the w*nkers from Brainiac have contributed (in the name of Mammon, what else??)
I’d seriously like to see how he’ll compare the reaction enthalpy of Li and Cs reacting with water. It’s not just M(s) + H2O(l) === > MOH(aq)
+ ½ H2(g) (R.1) that takes place: most of the formed hydroxide will dissolve in water, giving rise to solvation enthalpy (as anyone who has ever
dissolved some NaOH in water will know!) Even in a bomb calorimeter measuring the reaction enthalpy of R.1 will not be separated from that different
heat. I bet for his Li/Cs comparison he’ll actually be comparing apples and oranges… The actual heat of formation of the various MOH compounds is
almost certainly determined indirectly.
Searching for ‘thunderf00t’s blog (wasn’t that easy), I assume this is it:
http://thunderf00tdotorg.wordpress.com/
Although it pretends to be about ‘Science and Education FTW!’, the latest article is about cold fusion (something that’s been debunked about a
decade ago!), the rest really seems to be mostly an anti-Islamic screed.
[Edited on 1-12-2011 by blogfast25]
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Nicodem
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Solutions of electrons are blue, that's why dissolved alkali metals give intensely blue colored solutions (e.g., sodium in liquid ammonia, potassium
in polyglymes, etc.). Solvated electrons in protic or reducible solvents have a very short life due to obvious reasons, but with the continous fresh
supply of potassium, perhaps there is always enough present to produce some coloration at the solid-liquid or solid-steam interface. The greenish in
the video looks very similar to the blue of electron solutions. Solution of anion radicals are also intensely blue of the same hue (e.g., solution of
sodium benzophenone ketyl).
Quote: Originally posted by blogfast25  | This guy is largely a bullshitter (at least on this occasion).
For starters, the cesium part of the Brainiac video was 100 % fraudulent, to which they [Brainiac] admitted:
...
If Pompous Git didn't know that then he doesn't know much, as far as I'm concerned... |
Looks like someone did not bother to watch the video till the end. It is not polite to make accusations before actually see the entirety of the
evidence. The "THIS VIDEO IS FAKE" in big red uppercase letters is not there for nothing.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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blogfast25
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| Quote: Originally posted by Nicodem | | Looks like someone did not bother to watch the video till the end. It is not polite to make accusations before actually see the entirety of the
evidence. The "THIS VIDEO IS FAKE" in big red uppercase letters is not there for nothing. |
Nowhere in the video does he state the Brainiac cesium thing was a fraud. For all we know he's referring to his own video. Call me what you want but I
got the impression he didn't know the 'cesium footage' was fake.
At one point he even states: 'Cesium, which can do this:', cue the fraudulent 'Cs explosion'...
[Edited on 1-12-2011 by blogfast25]
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Neil
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BWAHAHAHAH wtf Blogfast? Talk about spastic knee jerk reaction -
http://www.youtube.com/watch?v=jhg0WsINmPc&feature=relmf...
Taadaa, the video was part of several.
As for green gas... the all might google hath this to sayith
From here;
"A Lecture Experiment with Potassium.—Mr. H. Kaem
merer communicates the following item to the German Chemical Society, upon a more practical and satisfactory me'.hod of showing, experimentally, the
green color of potassium vapor. The experiment is generally performed by simply heating a fragment of the metal in a test-tube. In this manner,
however, the color of the vapor is only visible for a few seconds, and not at all satisfactorily, inasmuch as its oxidation transpires almost
instantly after its formation.
The experiment may be made much finer and upon a larger scale, if the potassium is vaporized in a tube of about a foot in length, placed horizontally,
and through which a stream of hydrogen gas is passed during its continuance. Conducted in this way, the experiment is far superior to that first
named. The wide tube is speedily filled with the beautiful green vapor of the metal, which deposits itself upon the cool portions of the tube as a
lustrous metallic mirror, while the hydrogen escaping from the opposite end (the tube having been drawn out to a narrow opening for the purpose), may
be inflamed, and burns with a rich violet light, giving off at the same time thick clouds, from the formation of potassa."
Or from here...
ABSORPTION-SPECTRA OF POTASSIUM AND
SODIUM AT LOW TEMPERATURES.*
By H. E. ROSCOE, F.R.S., and ARTHUR SCHUSTER.
"In order to obtain the absorption-spectrum afforded by the well known green-coloured potassium vapour, pieces of the clean dry metal were sealed up
in glass tubes filled with hydrogen, and one of these was then placed in front of the slit of a large Steinheill's spectroscope furnished with two
prisms having refracting angles of 45° and 60°. The magnifying power of the telescope was 40, and was sufficient clearly to separate the D lines
with one prism. A continuous spectrum from a lime-light was used, and that portion of a tube containing the bright metallic globule of potassium was
gently heated until the green vapour made its appearance. A complicated absorptionspectrum was then seen, a set of bands (a) in the red coming out
first, whilst after a few moments two other groups appeared on either side of the D lines, the group fi (less refrangible) being not so dark as the
group y. These bands are all shaded off towards the red, and in general appearance resemble those of the iodine spectrum. In order to assure ourselves
that the bands are not caused by the presence of a trace of an oxide, tubes were prepared in which the metal was melted in hydrogen several times on
successive days until no further change in the bright character of the globule could be perceived. On vapourising the metal, which had been melted
down to a clean portion of the tube, the bands were seen as before, and came out even more clearly, the globule, after heating, exhibiting a bright
metallic surface. An analysis of the potassium used showed that it did not contain more than 0 8 per cent of sodium, although, of course, the double
line D was always plainly seen.
In order to ascertain whether an alteration in the absorption-spectrum of the metal takes place at a red heat, fragments of potassium were placed in a
red-hot iron tube, through which a rapid current of pure hydrogen gas was passed, the ends of the tube being closed by glass plates. The magnificent
green colour of the vapour was clearly seen at this temperature on looking through the tube at a lime-light placed at the other end. Owing, doubtless,
to the greater thickness or increased pressure of the vapour, the bands seen by the previous method could not be resolved by the small spectroscope
employed, the whole of the red being absorbed, whilst a broad absorption-band in the greenish yellow was seen occupying the place of the group y."
Clearly a bullshitter.
[Edited on 1-12-2011 by Neil]
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Endimion17
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Yes, it belongs to a series of videos. He's not bullshitting. He just has a keen sense of style when presenting his ideas, and I like it.
I've watched only few of his uploaded videos, so I can't really say anything specific about the guy, though his clip titles imply that this is an
intellectual.
Neil, thank you so much for the finding.
[Edited on 2-12-2011 by Endimion17]
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Sedit
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If one purged a test tube with Helium and heated a piece of Lithium it should yeild some results without the need for argon correct? I ask because I
know some complexes have been made with Helium in the past and I would expect vaporized Akali metals to be rather reactive although I doubt reactive
enough to force Helium into reacting.
I believe I have Helium around and Lithium is not so much of a problem, I would love to see colored vapors coming out of a silvery metal if possible.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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blogfast25
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| Quote: Originally posted by Endimion17 | I've watched only few of his uploaded videos, so I can't really say anything specific about the guy, though his clip titles imply that this is an
intellectual.
[Edited on 2-12-2011 by Endimion17] |
I really don't think people who seem to think there's a war between science and religion should be described as 'intellectuals'. And his anti-Islamic
stances are Classic (TM) 'War of Civilisation' tropes: banal and racist.
So where's his vid with the results of Li v. Cs? I'd really like to see that one!
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Neil
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He is against fanatical adherence to any doctrine, given his #1 series is about anti science attitudes promoted by the fundamental Christian right, I
fail to see how you got Muslim hater out of it. His anti people-chopping-off-peoples-head-because-someone-drew-a-cartoon-of-the-prophet videos are,
you know, anti head chopping.
Going back to the topic, it seems that H is needed to get the green out of the K. There are a number of vapour/wave length studies on K which were
done in the last 20 years but I could not access any of them :'(
There are papers that report reds with Na/Mg combinations and yellows and possibly reds with K/Na. All of the one I was able to lay my eyes on were
old with an e.
This one talks about green from sodium.
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blogfast25
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| Quote: Originally posted by Neil | I fail to see how you got Muslim hater out of it. His anti people-chopping-off-peoples-head-because-someone-drew-a-cartoon-of-the-prophet videos are,
you know, anti head chopping.
|
Click on the link I provided. Among other things he promulgates the classic Islamophobic trope that 'Mohammed was a pedophile'. Why is this deeply
Islamophobic? Well, let us first assume that Mohammed really did consume this marriage to Aisha, just for argument’s sake. What does that
tell us about the religion itself? That in Islam pedophilia is OK, nay, to be practiced even? Pedophilia is as forbidden and taboo in Muslim societies
as it is in any other. So claiming that the ‘prophet’ was a pedophile is nothing more than base smearing and stereotyping of an entire group of
people, no different from the sort of antisemitic tropes we’ve almost managed to free our societies from. It’s also deeply anti-intellectual.
If atheism would be smeared because a believer found a pedophile atheist somewhere he’d be upset (a bit more than just 'upset', I'm guessing).
What’s good for the goose is good for the gander.
As regards being ‘anti head chopping’, aren’t we all? But are you (and him) also against the mindless slaughter of Muslims by means of automated
drones? Or does that not count because we keep 'clean hands'?
At the end of the day 'Thunderf00t' is an ordinary Joe with good diction, a high opinion of himself and racist tendencies.
[Edited on 2-12-2011 by blogfast25]
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Endimion17
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As I've said, I've watched only few of his videos. Please, let's avoid turning this thread into a philosophical battlefield.
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Neil
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| Quote: Originally posted by m1tanker78 | Maybe irrelevant but this reminded me of some observations I made a while back with warm sodium oxidizing in air. I never could figure out exactly
what caused a ghostly blue glow around the warm sodium. I tried to reproduce and take some pics and vids but my camera distorted the color to a
red-violet so I never published them.
http://www.sciencemadness.org/talk/viewthread.php?tid=15769#...
As far as the green stuff: my knee-jerk thinking takes me first to the hydride. I've made and seen NaH in pure white, grey, and OD GREEN. I'd need to
double check my notes, though.
Tank |
Ah! I came across a possible reference.
"The absorption spectrum of sodium vapour is by no means so simple as has been generally represented. The fact that the vapour of sodium in a flame
shows only the reversal of the D lines, while the vapour, volatilized in tubes, shows a channelled-space absorption corresponding to no known emission
spectrum, appears to be a part of a gradational variation of the absoqition spectrum, which may be induced with perfect regularity. Experiments with
sodium exhibit the following succession of appearances, as the amount of vapour is gradually diminished, commencing from the appearance when the tube
is full of the vapour of sodium, part of it condensing in the cooler portion of the tube, and some being carried out by the slow current of hydrogen.
During this stage, although the lower part of the tube is at a white heat, as long as the cool current of hydrogen displaced metallic vapour, on
looking down the tube it appeared perfectly dark. The first appearance of luminosity is of a purple tint, and, with the spectroscope, appears as a
faint blue band, commencing with a wave length of about 4500, and fading away into the violet. Next appears a narrow band in the green, with a
maximum of light, with a wave length of about 5420, diminishing in brightness so rapidly on either side as to appear like a bright line. This gretn
band gradually widens, and is then seen to be divided by a dark band with a wave length of about 5510. Red light next appears, and between the red and
green light is an enormous extension of the D absorption line, while a still broader dark space intervenes between the green and the blue light. The
dark line in the green (wave length about 5510) now becomes more sharply defined. This line appears to have been observed by Roscoe and Schuster, aud
regarded by them as coinciding with the double sodium line next in strength to the D lines, but it is considerably more refrangible than that..."
Taken from here.
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