Copyright 2003 Theodore W Gray
| Introduction, plasma ball colors: |
|
Right now I use pure argon, which gives me a bright intense pink color
streamers at the terminal, which fade to orange and then to purple at
the glass (it really does have a distinct orange tint, which is not
captured by the camera in any of these photos, but it is very
pretty). 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. (Please note, higher amperage gives more plasma
streamers, and higher voltage fills a bigger globe, a big globe will
not have as many streamers as a smaller one unless you really boost the
current or use different gases (even my Tesla coil will only make a few
streamers in my prototype globes). Also note, lower pressures
favor more streamers, but they will be dimmer, play with gas pressure
and gas choice to get the right number of streamers, but don't just
keep increasing the power: you'll hurt yourself and make a system that
keeps committing suicide whenever you turn it on for longer than 10
seconds.) |
| Pure Gases: |
| Helium: |
| Very bright, I get blue and purple, but different 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 is not be 100% pure (Mr. Gray pointed out to me, that the helium sold in disposable containers is mixed with a substantial amount 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 gases, they are a rough indication only, both of the spectrum tube photos taken by Mr. Gray are in fact the same color. Helium 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 many years, 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 different (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 because it is relatively inexpensive, looks awesome, and because of the low ionization voltage power supplies can be constructed less expensively. It is frequently mixed with other gases, where the streamer is dominated by the other gases color but the pads on the glass are orange or pink. Plasma Globe photo courtesy of Mark Dunn, Spectrum tube photos courtesy of Theodore Gray. |
| Argon: |
| Kind
of dim but not bad at all if the pressure is high enough, it has very
low ionization voltage, Orange at mid to high pressures, red/purple
(violet) at 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 at normal flyback voltages, you need a breakout point). An
interesting fact is the atmospheric pressure arcs transmit no pain when
they strike your fingers (ask me how I know, but don't try it.)
Low pressures form a maroonish cloud. 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. |
| 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, though by the color, and again be wary of colors
taken by cameras, it looks like Mark's has a tiny amount of air
contamination. Very bottom are spectrum tubes courtesy of
Theodore Gray (note once again the color difference, the left most
image I believe to be of a higher pressure, due to it's very blue
appearance, as grounded high pressure argon is very blue, not purple
like my pictures suggest). |
| Krypton: |
|
Very cool! gives white ribbony lightning like streamers when used pure
(it looks much like atmospheric argon) but it is usually mixed (because
it is expensive), tends to give white, gray, or green when mixed,
(colors vary a lot with pressure, current, and the other gas if there
is one). 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, pure white, but they don't look it... |
| This is a special krypton globe. It is unique because the discharge terminal is a tungsten electrode sealed with green glowing uranium glass. What cannot be seen here is the interesting color "specs" in the discharge. This is probably do to a tiny amount of some halogen "contaminants" which are intentionally added. Professional globe makers often add tiny amounts of strange gases (sometimes they are called catalysts and examples are bromine, and iodine) they do this because these gases ionize and emit ultraviolet light. This would seem pointless as we cannot see ultraviolet light, but what happens is the high energy photons strike already high energy Xenon or whatever and kick it up another notch, so that the light emitted is brighter and often a slightly different color. Pretty clever huh? |
| Xenon: |
|
A lot like krypton with it's properties, Here is a plasma globe made
with Pure Xenon (it is called the electric blue effect).
Spectrum tubes show white to blue, but they often differ from colors in
a plasma globe, Xenon does tend to add blue to everything you mix it
with, and it is used in xenon flash bulbs where it is very bright white
(from higher current). (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!) Plasma globe photo courtesy of Marko
Nero (note the interesting plasma characteristics are unlike most on my
page, I am told that this is not do entirely to the gas, but has a lot
to do with top secret frequency/pressure combinations, as well as
additives like explained about. There may be other factors as
well that the professional globe builders would like to keep secret,
also note the color is supposedly more purple than it appears in this
picture.) Spectrum tube photos courtesy of Theodore Gray. I have
seen other Xenon tubes and globes that are very white, and hopefully I
will have pictures up soon. |
| Noble Comparison: |
| 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 still doesn't look right despite being the same tube in the above photo. |
| 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. Someday when I am rich (as if...) I will definitely try it, who knows, maybe the emitted radioactive particles will continually change the color for an ever unique display, or maybe it will be pink like a lot of other boring gases. |
| 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
significantly dimmer.
Very
high ionization voltage
is needed (only my good compressor can get it to ionize wiht my
flyback, wheras with the nobles my normal compressor will do
fine. Air will also turn your electrode back 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 I can all but guarantee it would be purplish in my globe). Once again spectrum tubes usually show purple (different pressures and different frequencies produce different colors in any gas, But nitroge nis particularly bad for this. it is a complicated but well understood science; what is not understood is why gas mixtures are the colors and patterns that they are, no science or formula can predict why a xenon neon mix will have blue streamers and pink pads). |
| Carbon dioxide: |
|
I didn't try it yet pure, 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 emits a great deal of infra-red frequency light. In
my limited experience diatomic gas molecules are dim and undesirable |
| 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, but it is too bright to discern color, and is filtered by the atmosphere) 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 delicate 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 shifted determines the energy 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 may blind you) many are pretty much
"invisible" (as most of the energy produced is in the ultraviolet or
infra-red range). Mercury is blue at low currents, and green at
high currents (I have some liquid mercury but I am way to scared to try
it, the vacuum pump will be spitting it into the air around me, that is
bad news) aluminum is bright green-blue, but good luck vaporizing and
ionizing it with a low current plasma ball electrode!
Update: I tried a tiny bit of mercury (under very controlled
conditions (recycling and filtering the air from the globe,)) my
pressures are too high to evaporate it much so there is no change in
color, there, never try it, it is pointless and
dangerous. An interesting note, 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 (and over time leaves a dark film on the
inside of the glass.) 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 and beautiful 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, no matter what you are doing 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 from striking the
glass atoms at insane energies, 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 these globes 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 gif animation given to me by Mr. Dunn (he does not have enough bandwidth on his site for this full sized image, but it is worth downloading because it makes a great desktop background or screen saver!) The rightmost picture is mostly Xenon, with a little neon, same gases different 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 different 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
original, but the purple haze is more bluish than it appears, similar
to the left photo). |
| Argon Nitrogen Krypton: |
|
Purple lavender, with blue tips. Very similar to the light bulb
mixture, but with some krypton to increase it's "ribbonyness" and
intensity. Globe photo courtesy of Marko Nero (he made this one
himself!). |
| Helium Neon: |
|
Red-orange, and very bright with fuzzy streamers, some sources suggest
this combination gives blue and purple at just the right pressure and
gas ratio (I believe they are mistaken and they are thinking of xenon
neon, but cannot prove it. Helium doesn't ever show blue so I
have no reason to believe that mixed with neon, not strong in the blue
region you would get blue and purple). They use this mix to make
lasers. |
| Xenon Krypton Argon: |
|
Very blue, very interesting. Photo courtesy of Marko Nero |
| Neon-Argon: |
|
The absolutely lowest voltage requirement of any gas with 99.5% neon,
.5% argon, fuzzy streamers. Photo courtesy of Marco Nero. I
don't know the ratio of the mix in the picture, only the ingredients,
better examples of neon argon mixes are below in my new section "exact
mixes" that were generously given to me by Mike Davis, he is an
experimenter like myself but with the funds and glass to actually try
stuff. If you have questions about his mixes I can give you his
e-mail, or you can send him a you-tube message. |
| Argon-Helium: |
|
I had to mention this because I use it (although my 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). This is a picture of pure argon, I will make one
of argon helium when I have some time (more likely when I get pure
helium, I have a feeling it will look quite different pure, and without
oxygen). |
| Argon-Acetic Acid: |
|
Whilst experimenting with a newly constructed globe, I observed 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 fliers, 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 pictures were taken with a covered discharge
terminal, which as I suspected does help make arcs more numerous.
I tried putting in more argon and found the operating pressure greatly
increased, that is the bottom two pictures. Whatever impurity is
responsible I would love to isolate it and experiment with it further,
as stated about strange gases in tiny quantities can have huge effects. |
| Neon-Nitrogen-Argon: |
| Gives
orangish white streamers with hot pink pads, 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. |
| Krypton Argon: |
|
Similar in color to Krypton Xenon, but the plasma characteristics
and color are a little different. This globe was made by Bill
Parker, and the photo is courtesy of Marko Nero. |
| 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! |
| Exact Mixtures: |
| Below
are some recipes given to me by Mike Davis, he is an avid Globe
hobbyist like myself, and has been doing this for a long time, so he
has an impressive resume. Feel free to make any of these in your
home lab, but do not reprint the formulas without permission from
myself or Mike, it
will be easy to get permission, just ask, we are not being obsessive,
it is just the principal of
the thing. If you want to contact Mike go to his you-tube profile
and send him a message, if you don't have an account I can forward you
his e-mail address. Anyway here is some of his work, I will have
more as he gets time to send the pictures. By the way, click on
his pictures to go to a you-tube video of his work, worth watching
trust me! |
| Neon Sunset: |
|
Neon approx. 270
Torr (Grade 5: 99.999%) Argon approx. 30 Torr (Grade 4.5 welding grade: 99.995%) Total approx. 300 Torr Neon Argon mix, very nice at approximate 25kHz. |
| Orange and White: |
| Neon:
200 Torr (Grade 5: 99.999%) Krypton: 100 Torr (Grade 5: 99.999%) Total 300 Torr (760 Torr=1.0 ATM) Very nice neon krypton mix that makes focused white streamers with orange finger like pads. |
| Green And Pink Plasma Globe: |
| GREEN
AND PINK PLASMA GLOBE 08/07/09 Xenon: 8-10 Torr (Grade 5:99.999%) Iodine 2-10ppm (Iodine vapor from crystals under neon in gas sampling tube) Neon: 350 Torr (Grade 5:99.999%) Total: 360 Torr Notes: This mixture shows soft, slow-moving ghostly green plasma tendrils with pink splashes that form thick green arcs at about 20-25 kHz when globe is touched. At 30-40 kHz the globe displays twirling green tendrils with rose-pink parasol tips or splashes and forms a bluish-white solid arc when globe is touched.Intensity and hue of green color changes over frequency range of 20-40 kHz. Tiny adjustments in amount of xenon cause very large changes in final image. Xenon must be added after neon very slowly with globe energized to see image resolve. If too much xenon is added and the plasma shifts to a red-blue image, it is nearly impossible to change the mixture back to show a green color. Iodine vapor level is also critical. Any contaminants left inside the globe during the filling process can cause green color to fade and plasma image colors to change to red mixed with blue. MLD Note: this mix is good for two effects, click on the left for a video of one effect, and the right picture for a video of another. |
| Red
White and Blue: |
| RED
WHITE AND BLUE PLASMA GLOBE 08-07-09 Xenon: 5 Torr 1%(Grade 5:99.999%) Krypton: 20 Torr 4%(Grade 5:99.999%) Neon: 425 Torr 95%(Grade 5:99.999%) Total: 450 Torr 100% Notes: Red-orange plasma core with mixed white and blue tendrils and red-orange tips and splashes, with very active and fast-moving plasma streamers. This is a color variation on the standard 95% Neon-5% Xenon (red and blue) plasma globe mix that is in widespread use. Total pressure could be reduced to as low as 300 Torr for less motion, but higher total pressure yields very sharply-defined plasma streamers.Using less krypton and more xenon would enhance the blue regions, but total krypton plus xenon level should remain at 5% to maintain similar motion. MLD |
| Sunburst Yellow: |
| Xenon
1 Torr (Grade 5: 99.999%
Xenon is
required for yellow arcs) Argon 4-5 Torr (Welding grade: 99.995%) Nitrogen 5 Torr (Medical Grade/Grade 5: 99.999%) Excess N2 ruins the effect Iodine vapor 10-14PPM (Added with Nitrogen from 250mL gas sample mixing chamber) Neon 294 Torr (adjust final pressure with Grade 5: 99.999% neon) Total 305 Torr (Gold color appears at 250-350 Torr) Disclaimer: Gold arcs may fade after time and only appear at specific frequencies (31kHz and 63 kHz) with high power settings. Experimental mixture: may contain traces of air. At low power settings or at other driver frequencies plasma is bright orange with purple hues in the plasma streamers. Excess nitrogen yields shades of orange and leads to dull color output. MLD |
| Red and Blue: |
| RED
AND BLUE PLASMA GLOBE 08-29-09 Xenon 20 Torr Grade 5 Xenon (99.999% Pure) Neon 360 Torr Grade 5 Neon (99.999% Pure) Total 380 Torr Notes: This mixture or one similar to it is often found in mass-produced plasma globes made overseas. It typically shows a red-orange core with sharp-focus sky-blue plasma streamers with bright red or orange tips that are constantly in motion. When large plasma arcs form they are usually a brighter blue and grow smaller “branches” or secondary filaments at the ends of the arcs. The blue color filaments can appear translucent and may be hard to see in direct sunlight. At some frequency settings many small blue and red filaments can form resembling a dandelion seed structure, blue trees with red leaves, or red flowers with blue stalks. The blue and red plasma effect is very stable over a large range of total pressure between about 240 Torr and 480 Torr, and is not easily degraded by contaminants in the globe. At lower total pressure the movement slows down, and at a higher pressure the plasma becomes more active. A ratio of 3-5% Xenon to 97-95% Neon by volume seems to work best. If a higher ratio of xenon to neon is used the plasma tendrils become very thin and less pleasing to watch, and at a higher total pressure the blue color in the filaments will intensify and the plasma tips can become a deeper red color. MLD |
| Purple and Orange: |
| PURPLE
AND ORANGE PLASMA GLOBE 08-31-09 Argon 30-50 Torr Grade 4.5 (99.995% for welding) Neon 300-350 Torr Grade 5 (99.999% Purity) Total 330-400 Torr Notes: This mixture produces a bright red-orange core and sharp-focus pink-to-purple plasma streamers with orange tips or surface splashes that are in constant motion. If the total pressure is lowered to about 300 Torr with the same ratio of gases the plasma tendril movement becomes much less active and the streamers become wider. If the total pressure is increased the streamers will become very sharp and more agitated. This is a purple and orange equivalent of the blue and red plasma globe mixture. The plasma image varies widely over a working frequency range of 20-80 kHz, so the same plasma driver that will be used to power a plasma globe with this mixture should be used to power an argon-neon mixture during the filling process. Small adjustments in the amount of argon in this mixture can produce large changes in its appearance and rate of motion. Since the argon provides the purple color and the neon the orange hue, if less argon and more neon are used the dominant color effect will be less pink/lavender/purple and more orange. Pink and Neon Orange Variation: If about 30 Torr of dry air is used in place of the argon and added to about 250 Torr of neon to make a total pressure of 280 Torr the plasma streamers will appear to have more of a pink and bright neon orange color scheme than purple and orange and will have softer, rounded plasma tips resembling plant or feather fronds with mixed red-orange and orange colors that will show a wiggling motion that can be adjusted by changing the total pressure of the mixture. This mixture would have better color if higher-purity argon is used. However, if small amounts of dry air are used to replace some of the argon, or if a vacuum system has a minor air leak this mixture will still continue to perform. MLD |
| My Filling Setup: |
| 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 balloons (which is not entirely pure, I will get better helium soon). |
| Gas Analysis: |
| One more thing, If you have a spectroscope, you can find out exactly what gases are inside a plasma globe, by careful comparison with samples of pure gases. 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. |
