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Argon is the most common and cheapest of the nobel gases. It can be extracted from air by cooling the air down to the point where it liquefies, then doing a fractional distillation of the resulting liquid to isolate the argon fraction. I've seen machines that do this for sale on eBay for a few thousand dollars: Buy you own private argon factory!
Some common light bulbs are filled with argon, while fancy high-intensity ones are filled with krypton or xenon, which allow the filament to burn at a higher temperature. It's also used to fill high-efficiency double-pane windows.
I have a tank of argon gas in my office for filling bottles holding air or moisture sensitive samples: It's cheap and relatively easy to handle, and is therefore commonly used as a shield gas. "Heli-arc" welding is a technique in which an inert gas is blown around the welding tip to protect the hot metal from oxidation. It's named after helium, but actually done using argon, because argon is cheaper.
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Ordinary light bulb.
Exotic light bulbs are filled with xenon or krypton, but ordinary everyday ones are filled with argon, because it's cheap. This one happens to be a burned out bulb from a microscope, I'm using it just because it's the right size to fit in the table.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 15 April, 2002
Price: Donated
Size: 1.5"
Purity: >90%
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Antique reagent flask.
I got a set of five different noble gas flasks on eBay for $13.50, which seemed like a good deal even though the seller described them as "probably empty". I very much doubt, however, that they are empty: At the bottom where the flask meets the tube, there is a tiny inner breakaway seal that is completely intact on all five of them. There's no visible way for the gas to have escaped. I've learned that one normally uses a steel ball, held up with a magnet, to break the seal: When you've hooked up and flushed out all the connecting tubes, you pull away the magnet and the ball drops onto the seal, breaking it and releasing the gas.
After many unworkable suggestions for proving whether the gasses were still in there, several people came up with the idea of using a high voltage transformer, such as one finds in those now inexpensive plasma ball novelty lights, to try to set up an arc inside the flask, and identify the gas from the color of the discharge. Whether this is possible is sensitive to the pressure of the gas, which is not known.
Fortunately, it worked beautifully on three out of the five, and proved beyond a reasonable doubt that those three at least contain the gas claimed. The others almost certainly failed because the type and pressure of gas in them does not support an arc, not because they are empty. In fact, if they were empty, I would have gotten an arc, because the arc works through up to about half an inch of ordinary air.
You can see pictures of all the arcs along with a picture of the display stand I built for them (between 10PM and midnight of the evening they arrived) a using some of the same Carlson Maple used for the noble gas tiles on the table.
By the way, isn't it a cute oxymoron: Reagent-grade non-reactive gas.
Source: eBay seller tictoxx@yahoo.com
Contributor: Theodore Gray
Acquired: 28 August, 2002
Price: $3
Size: 9"
Purity: 99.95%
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Mounted arc tube.
In some ways, gases are a pain from a sample point of view. With the exception of chlorine and bromine they all look exactly the same: Like nothing at all. My beautiful set of noble gas flasks is beautiful because of the flasks, not what's in them, which is indistinguishable from plain air or vacuum. (So much so that I got them for a bargain price because the seller thought the were empty.)
But set up an electric current through almost any gas, and things are completely different. The current ionizes the gas, and when the electrons fall back into their orbits, they emit light of very specific frequencies. These spectral lines can easily be seen with even a very cheap pocket spectroscope, and they give the glowing tubes very unusual colors. So unusual in fact that they are basically impossible to photograph. The pictures here simply don't look at all like the real colors of these tubes, which cannot be represented by the limited red, green, and blue mixtures available in computer or printed photographs.
David Franco helped arrange these tubes, which were made by a guy who specializes in noble gas tubes and Geissler tubes (click the source link). I have tubes installed in each of the five stable noble gas spots in the table, hooked up underneath to a high voltage transformer. They are really quite beautiful. On my Noble Rack page I have all the pictures collected, along with pictures of arcs I made in my other collection of noble gas flasks.
Source: Special Effects Neon
Contributor: Theodore Gray
Acquired: 22 November, 2002
Price: $35
Size: 2.5"
Purity: >90%
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Sample from the Everest Element Set.
Up until the early 1990's a company in Russia sold a periodic table collection with element samples. At some point their American distributor sold off the remaining stock to a man who is now selling them on eBay. The samples (excepted gasses) weight about 0.25 grams each, and the whole set comes in a very nice wooden box with a printed periodic table in the lid.
To learn more about the set you can visit my page about element collecting for a general description and information about how to buy one, or you can see photographs of all the samples from the set displayed on my website in a periodic table layout or with bigger pictures in numerical order.
Source: Rob Accurso
Contributor: Rob Accurso
Acquired: 7 February, 2003
Price: Donated
Size: 0.2"
Purity: >99%
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High pressure cylinder.
This cylinder contains 20 cubic feet of argon under about 2000psi of pressure. Or at least it did when I first got it: I use it to purge sample bottles of air-sensitive element samples before re-closing them, so it's slowly getting used up. When it's empty I'll get it refilled: Argon costs about fifty cents a cubic foot, once you've paid for the cylinder and regulator needed to handle it. Those cost a good bit more, but can be reused indefinitely.
Gases like argon, helium, nitrogen, oxygen, carbon dioxide, and of course acetylene are easily available at any welding supply store. They are all set up to re-fill such cylinders on a routine basis (in fact, it's their main business). Larger cylinders are typically leased to you, but small ones like this you buy outright.
Source: Claudin Welding Supply
Contributor: Theodore Gray
Acquired: 18 February, 2003
Price: $10
Size: 16"
Purity: 99%
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