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Plasma Globe Colors
Right now I use an
argon-helium mix, which gives me a bright
intense pink color streamers at the terminal, which fade to lavender
and
then to blue at the glass. There are a multitude of gases used
in
making plasma balls, And I shall list a few here. Some of the
pictures are my own, some belong to other people, I have given them
credit when they are not mine.
Plasma ball colors:
Helium:
Very bright, I get blue and purple,
but differant reports indicate a wide variety of colors (helium
spectrum
tubes usually show bright yellow-orange as seen below in a digital
image taken by Theodore Gray (click on the tube to be taken to his site
concerning that element, and the copyright link next to it to go to his
periodic table home page, they are very informative pages and worth
looking at), but these can vary from plasma
ball streamers, and my helium may not be 100% pure (Mr. Gray pointed
out to me, that the helium sold in disposable containers is mixed with
a substancial amout of oxygen to prevent helium huffers from dying!),
also do not trust
the colors displayed on this page, digital images do not work correctly
for ionized gasses, they are a rough indication only, both of the
spectrum tube photos taken by Mr. Gray are in fact the same
color. It works decent
at
atmospheric pressure in small globes giving fuzzy violet
color (a little air in the mix helps, you can even turn a regular
helium balloon into a super cheap plasma globe, see middle
pictures). Lower pressures
tend to
form a purple cloud, and note, helium will
not
stay in what you put it in,
it will
eventually leak out even if other gases won't (it is probably the
smallest
molecule in the universe) it looks cool but it just will not stay (kind
of like a bad dog, it keeps running away!) if you have a very well
constructed globe, it will stay a while, but not forever. Please
note, I am going to update my helium information as soon as I get some
pure helium to work with, I may find the colors are radically differant
(yellow maybe?)
Neon:
Extremely bright, lowest
ionization voltage of any gas (except special mixture, see below), it
gives blurry red streamers with
reddish orange
ends, it is favored by plasma globe makers everywhere, and is
frequently mixed with other gases. Plasma Globe photo courtesy of
Mark Dunn, Spectrum
tube photos courtesy of Theodore Gray.
Argon:
Kind of dim but not to bad if the pressure is
right, it has very low
ionization
voltage, purple-lavender (pink when voltage increases,
like at the
center, or in a grounded arc) streamers that get darker at the ends (It
looks nice, but is dim and a little to blurry
for my
taste at normal low pressures) it will work extremely well at
atmospheric pressure if
completely pure, especially in a smaller container, giving bright white
lightning
streamers (I have pictures of the effect below, when testing with my
Tesla coil,
the tube bringing the gas in lit up all the way to the tank,
which looks cool, but
this eventually ruined the tube, but just for experimentation sake, I
made a "plasma ball" out of a juice jug using pure argon at atmospheric
pressure, and my flyback driver, but note, a smooth terminal will not
work, you need a breakout point, unless you have really high
voltage, more than a normal flyback can put out). Low pressures
form a maroonish cloud, but it is not as bad as helium, and covering
the
center
electrode would probably help. One small and interesting note, at
a higher pressure (barely low enough to establish an arc), most gases
do not create a standard pad at the glass surfaces, but fingers like
birds feet, that
disappear when the frequency rises from the transistors warming up,
just thought you might like to know. Spectrum tube
photos courtesy of Theodore Gray, Argon globe is
Mark's as labeled, the other
pictures are mine.
Mark
Dunn
Copyright
2003 Theodore W Gray
The top left and center is pure argon, both free, and grounded to
my finger (pretty intense huh?),
to the right is low pressure grounded, with a little air contamination,
bottom middle is pure argon. Very middle is an Argon globe by Mark
Dunn, notice how similar it is to the mine directly above it.
Very bottom are spectrum
tubes courtesy of Theodore Gray (note once again the color differance,
the left most image I believe to be of a higher pressure, due to it's
very blue apperance, as grounded high pressure argon is very blue, not
purple like my pictures suggest).
Krypton:
Dimer but cool! gives white ribbony lightning
like streamers when used pure (it looks much like atmospheric argon,
but dimmer and grayer), but it is usually mixed (because it is
expensive, and kind of dim by itself), tends to give
gray to green to yellow
streams when mixed, and mixing makes it brighter (colors vary a lot
with pressure, current, and the other gas if there is one). It
makes the
streamers more focused and less fuzzy (goes well with neon).
Photo courtesy of Mark Dunn, Spectrum tube photos courtesy
of
Theodore Gray, you can really see here that colors in
photographs do not represent real life, these pictures are all pretty
much the same color, but they don't look it..
Xenon:
A lot like krypton with it's properties, I
don't know what
it looks like alone in plasma globes, (spectrum tubes show white to
blue, but they often
differ from colors in a plasma globe), but it does tend to add blue to
everything you mix it
with,
in spectrum tubes it is blue white as I said, and it is used in xenon
flash
bulbs
where it is very bright white. (Save your rubles if you want to
buy
some, it costs twice as much as krypton where I have seen it available,
and I
can't afford krypton yet!) Spectrum tube photos
courtesy of Theodore Gray.
Copyright
2003 Theodore W Gray
Below in this shot of all the noble spectrum tubes together, you
can easily compare brightness, seeing that neon is by far the brightest
followed by helium, and that once again krypton doesn't look right
despite being the same tube in the above photo.
Copyright
2003 Theodore W Gray
Radon: the
last of the noble gases, nobody uses this, so I have no idea what it
looks like. This may be because it is radioactive (although radon
poisoning comes from the atom lodging in your lung and irradiating it,
not from long
distance X-rays coming through the walls, so it would probably be
harmless trapped in glass) or
this may be because it is so large, it is more difficult to ionize, or
gives
lame colors, or whatever. It is not really rare, most basements
have some, and collecting it is simply a matter of liquefying air from
the ground, and
distilling it out. It probably would give extremely focused
streamers because the larger nobles seem to do so.
Air:
The most common
amongst hobbyists is much dimmer than argon, very deep purple with
bluish
pink tips, higher pressures form
weak streamers, lower pressures form a cloud much like helium, only
dimmer (about this cloud thing,
using
a covered terminal changes thism, making it more uneven, a higher
frequency changes it's properties as well,
but it actually looks kind of neat, so you may want the effect!)
Very
high ionization voltage
is needed (only my good compressor can get it to ionize with
my flyback, whereas
with the nobles, my weak compressor will do
fine). It turns your electrode black if it is not covered.
Nitrogen:
Said to be everything from orange to gray
to purple to pink to bright or dark blue (I didn't try it pure, but air
is 70% nitrogen, so it
would probably be purpleish in my globe). Once again spectrum
tubes usually
show purple, but even they vary with this gas (different pressures and
different frequencies produce different colors in any gas, but
nitrogen is particularly bad for this, it is a
complicated science, one which I may use as a research project some
day).
Carbon dioxide:
I didn't try it, and have not found a picture, but is said to
be brighter than argon, and very white, it will turn your electrode
black worse than air alone. It is commonly used to make gas
discharge
lasers, as it emitts a great deal of infra-red frequency light.
Water Vapor:
Extremely high voltage necessary for a good arc (all it does is make a
faint purple glow on my discharge terminal), which is a shame because
it is a beautiful purple-blue color, but it is to dim to photograph.
Methane, Propane, Hydrogen:
Don't try these unless you really don't like your face, but
hydrogen
tends to be blue to red in spectrum tubes or both depending on current
and polarity in the case of DC (an example of ionized hydrogen is the
sun) I don't know
about
the others. Think about it, what do methane, propane, and
hydrogen have in common, which would make them less that ideal for
sealing them inside a glass globe, and exposing them to an electric
flame?) The reason
gas colors
vary with voltage current and temperature, is that the dominance of
each color in the spectrum of the element changes as voltage
current and frequency change. The light is produced by electrons
shifting orbitals and the number of orbitals the shift determins the
number of photons they emit, so higher current is brighter. Does
it all make better sense now?
Mercury or metal vapor:
Once again, unless you have serious self-esteem issues, don't try these
(too much ultraviolet light mayl blind you) many are pretty
much
"invisible" (as most of the energy produced is in the ultraviolet
or infra-red range), blue at low currents, and green at high currents
in the case of
mercury (I have
some liquid mercury but I am way to scared to try it) aluminum is
bright
green-blue, but good luck vaporizing and ionizing it with a low current
plasma ball
electrode!
You can observe the different colors of metal
plasma
by using a high amperage (like a microwave oven transformer supply)
Jacobs
ladder with rungs constructed of these materials, but once again
proceed at your own risk. I once observed vaporised tungsten in a
broken light bulb running under a weak Tesla coil, I have been unable
to
reproduce this effect until recently, but amongst the regular orange
purple
plasma
filaments (caused by argon nitrogen mixture plasma filaments), there
was a
thick blue stream between the gap in the
filament (it was seeking a ground), which was so difficult to ionize it
remained up to a half a second after the coil was shut off. You
can
also observe metals vaporised in a (drum roll please...) microwave
oven,
now is the time to have the concerned parent reading over your shoulder
look away, (actually if you are not old enough to buy a new microwave
yourself, you should look away as well). Iron produces orange,
copper
purple,
and
aluminum a blue green so intense it burns your eyes, so stick with the
Jacobs ladder, that way you can stand to look at it for more than a
second. Actually if you are insane enough to deliberately put
something
in a microwave that doesn't belong there, please for the love of all
that is good, don't leave it on more than a second after plasma forms,
or you could damage yourself and the microwave. Another note of
safety
if you build one of these suckers, if you ever, and I mean ever, see
glass begin to glow
green, turn it off immediately, dreaded cathode rays cause this effect
if
voltage
is high enough or pressure is low enough. Cathode rays
are caused
by
electrons leaping directly from electrode to glass, and when they get
there they emit harmful X-rays, which will
rearrange the weak hydrogen bonds in your DNA and trust me, you are
better off with your DNA where
God put it, not where your crazy little device wants it. If you
seriously consider building one of these, you must read my Tesla coil
safety page, as most of the information is applicable here as well.
Common mixtures:
Neon-Xenon:
95% neon with 5% xenon
gives the classic pink and blue with focused streamers look as seen in
my Radio Shack globe, and this great photo of Mark Dunn's, who is a
fellow plasma
enthusiast
(He made this globe himself, for more information visit
http://www.teslaboys.com/Plasma/index.html
by clicking here, or click his name below each image).
Also, this picture is a link to a dynamic giff animation given to me by
Mr. Dunn (he does not have enough bandwith on his site for this full
sized image, but it is worth downloading because it makes a great
desktop background or screensaver!) The rightmost picture is
mostly Xenon, with a little neon, same gasses differant proportions,
notice how dissimilar they look.
Neon-Xenon-Krypton:
95% neon with 2.5% xenon
and 2.5% krypton is similar to the above except green and orange.
Photo courtesy of Mark Dunn (once again, check out the dynamic image by
clicking the picture).
Argon-Nitrogen:
Purple, with a hint of orange-gray, this is a common mixture in cheap
globes, and is also used as a shield gas in light bulbs, container size
has to do a lot with perceived color, as seen in these two differant
sized light bulbs, the smaller right bulb has a distinct orange
appearance often seen in nitrogen spectrum tubes (actually, my camera
did not pick up on the orange as it was a frequency it could not "see",
but I edited the file to look like the origional, but the purple haze
is more bluish than it appears, similar to the left photo).
Neon-Argon: The absolutely lowest voltage
requirement of any gas with 99.5% neon, .5% argon, fuzzy streamers, it
doesn't look that great as it is too fuzzy, and mostly just a cloud
reports say, but pressure, and current, and voltage, and frequency are
all important, so I will not promote or deny this claim since I haven't
seen it myself.
Argon-Helium: I
had to mention this because I use it (althopug hmy helium is not pure,
so technically it is Argon-Helium-Oxygen), gives blue-purple pads
with pink streamers, tends to have dark and light alternating colored
bands in the streamers at lower pressure,
and the higher current streamers (grounded ones) have a very distinct
orange
tint, which cannot be picked up by my digital camera with it's limited
optical range (but orange is cool! trust me).
Argon-Acetic Acid: Whilst
experimenting with a newly constructed globe, I observerd a very
interesting effect, at first I believed it was caused by air leaking
into my system, until the color radically changed into a color which I
have never observed before, a very pale fuzzy purple-white, with bright
grounded arcs and dim free flyers, no doubt caused by acetic acid fumes
leaking into my globe from RVT silicone, shortly after taking these
pictures something in my globe power supply exploded, so I could not
take more, note
the below picture were taken with a covered discharge terminal, which
as I suspected does help make arcs more numerous.
Neon-Nitrogen-Argon: Gives
orangish white streamers, with hot pink pads, and purple fingers so I
am told.
Krypton-Xenon:
Very striking lightning, in a blue color, with a dash of xenon in pure
krypton. Photo courtesy of Mark
Dunn.
Mark
Dunn
If you know of something I have
missed, and can prove its composition, and have a picture, please let
me know, I am itching to add onto this section!
Here are my argon and helium tanks, in my very messy basement lab
(where else do you put a makeshift lab? upstairs? I don't think
so!). The argon is for welding purposes, and the helium is a
disposable party tank for ballons (which is not entirely pure, I will
get better helium soon).
One more thing, If you have a
spectroscope, you can find out exactly what gasses are inside a plasma
gobe, I built a small one out of a CD, a paper plate and some duct
tape, which works great for looking at halogen lights and such, but my
plasma balls are to dim to view with it, so I'll keep looking for a
cheap professional one.
Home, Hobbies,
Plasma Ball.
Scott Bogard. 2007
