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Helium is the second most common element in the universe, representing about 10% of the total matter. (The other 90% is hydrogen, all other elements represent an insignificantly small fraction of the total.) While helium is very common in the universe, most of it is in the stars: on earth it is actually quite rare. It is created deep in the earth from the radioactive decay of uranium and thorium (which also gives the earth its internal heat), and is "mined" from natural gas and oil wells (it comes up with the natural gas and is separated and stored). It's also constantly seeping up from the ground all around us, but it is so light that almost all of it escapes into space fairly rapidly: There is very little in the atmosphere at any given time.
Helium is a nobel gas, which means it doesn't react with anything for all practical intents and purposes. It's used as an inert shield gas to protect things from oxidation. (For example, "heli-arc" welding, which uses a stream of inert gas to prevent oxidation of metal as it is being welded, is named after helium even though most heli-arc welding is done with argon because it's cheaper.)
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Disposable party balloon tank.
You can buy these lightweight tanks of helium at Walmart or any party supply store. They are thin-walled steel, not like the heavy gas cylinders used in welding, and only contain enough helium for about 30 balloons. On the plus side, they come with a supply of balloons and ribbon, so you're all set to entertain the kids with elements (at 75 cents a pop, so to speak).
Source: Walmart
Contributor: Theodore Gray
Acquired: 7 August, 2002
Price: $20
Size: 18"
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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The Universe. (External Sample)
The universe is only about 10% helium, but that's better than some of our other samples, and it's getting more pure with every passing billion years. As an external sample, this one is not physically located within the table, but rather in its complement. (This is the famous Hubble Deep Field image.)
Location: The Universe
Photographed: 3 October, 2002
Size: 6000000000000000000000000000"
Purity: 10%
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