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If carbon is the foundation of life, oxygen is the fuel. The reactivity of oxygen, its ability to "burn" just about anything, is responsible for a lot of what goes on in living things, not to mention what goes on in cars and furnaces. (Actually, the term "fuel" is often used to refer to the thing that is burned by an "oxidizer", so I'm speaking metaphorically when I say oxygen is the fuel of life. Technically oxygen is the oxidizer of life.)
Here on earth we take oxygen for granted because it's everywhere. But I think that when and if large scale space colonies are established, oxygen is going to take on almost mythical connotations. It will be the one thing that you absolutely, positively can't do without, not even for a minute, not if you want to live.
All very large rockets are based on burning kerosene with liquid oxygen: This is the only practical way to get a huge amount of controllable thrust. How much liquid oxygen? The Saturn V rocket, the largest ever built, burned two thousand gallons, almost eight cubic meters, of liquid oxygen per second. Just imagine the pumps that could do that! (And don't forget it's at -183C, just to make things interesting.)
Oxygen is found not just in organic molecules and rockets, but in a whole lot of inorganic compounds and minerals as well: Notice how many minerals are listed below, all containing oxygen bound into them in some form.
Alert reader Karen Pease saw me saying that "All" very large rockets burn kerosene, and points out that this is incorrect:This isn't really correct. The most powerful Soviet rocket ever built, in for example (the Energia booster to the Buran shuttle) was pure H2/O2 (LOX/LH). In the Vulcan configuration, it would have delivered notably more LEO payload than the Saturn V, although A) it only flew twice and never in that configuration, B) it delivered less thrust, and C) it was notably smaller in overall size because of the higher ISP (even with the low LH density). It was a response to the Space Shuttle, which uses LOX/LH along with boosters (largely aluminum powder and ammonium perchlorate). The European workhorse is the Ariane series, which, again, is LOX/LH.
LOX/Kerosene isn't used as commonly any more in comparison to LOX/RP-1; RP-1 (and similar fuels) are very similar to kerosene, but not exactly the same formulation. They're also trying to move more to strained-ring hydrocarbons, which provide better ISP with similar chemical properties. LOX/LH has been becoming much more widespread in rocketry because, while LH is a pain to deal with and has horrible density, you usually get about a 7:1 propellant/mass fraction instead of a 20:1 propellant fraction.
Also, not all oxidizers are LOX. In solid rocket boosters, for example, ammonium perchlorate is popular (like in the Shuttle). Nitrogen tetroxide, nitric acid, nitrous oxide, hydrogen peroxide, and many other oxidizers are still in use in various applications. Some that have been tested in the past have no oxygen. LF (liquid fluorine) has been tested, but it's only in-use application that I'm aware of is in FLOX (a mixture of mostly LOX, but part LF - better ISP than LOX and hypergolic with most fuels, but it corrodes the heck out of your engine, is a pain to work with, and makes things rather toxic in general).
Still, off the top of my head, I can't think of a single rocket oxidizer in current use today that doesn't have oxygen in it :) I could always dig through astronautix.com some, because one might just be slipping my mind ;)
- Karen Pease Iowa City, IA So, I'm still on safe ground saying that oxygen is the oxidizer of choice!
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 Natural sample, 21% Pure.
I collected this sample of naturally occurring air (21% pure oxygen) from about 20 feet away from the table in May, 2002. The sound for this sample is a beautiful 78% nitrogen, 21% oxygen wind sound borrowed from ftp://ftp.zib.de/pub/UserHome/Luegger/Urania/Sound/FX-03.WAV .
Source: Air
Contributor: Theodore Gray
Acquired: 18 May, 2002
Price: $0/Free like the air we breathe
Size: 2.5"
Purity: 21%
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Mini welding gas cylinder.
Cylinders like this are sold in any hardware store for use with small welding/brazing torches. They are nothing like the heavy, thick-walled oxygen cylinders used with real welding torches. But they are cheap and do contain actual oxygen.
Many people don't realize that when you use an oxy-acetylene cutting torch to cut steel plate, the acetylene is just there to get things started. Once the steel is hot enough, you turn off the acetylene and blow pure oxygen at the advancing cut. The oxidation (burning) of iron in pure oxygen releases enough heat to keep the reaction going, and a jet of high pressure oxygen can literally burn through four inch thick solid steel plate.
I learned this from Harry Barnhart, a thinking farmer who showed me how it's done one day many years ago.
Because the air around us is only about 21% oxygen, steel will burn in air, but it won't generate enough heat to keep the burning going unaided. In air, the steel will cool down and stop burning pretty quickly unless you give it extra heat. This is the principle of the plasma-arc cutting torch (pictured under hafnium), which uses just electricity and air to cut steel. As when you turn off the acetylene in an oxy-acetylene torch, the steel itself is the fuel that powers the cutting action, but without pure oxygen to energize things, the plasma-arc cutter has to use an electric arc to supply the necessary extra heat.
Another fun thing you can do with oxygen in liquid form is use it to speed up the grilling process. The classic documentation for this was available here, except that it's been removed because of the concerns of the university that had been hosting it.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 5 August, 2002
Price: $5
Size: 12"
Purity: >95%
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Sample from the RGB Set.
The Red Green and Blue company in England sells a very nice element collection in several versions. Max Whitby, the director of the company, very kindly donated a complete set to the periodic table table.
To learn more about the set you can visit my page about element collecting for a general description or the company's website which includes many photographs and pricing details. I have two photographs of each sample from the set: One taken by me and one from the company. You can see photographs of all the samples displayed in a periodic table format: my pictures or their pictures. Or you can see both side-by-side with bigger pictures in numerical order.
The picture on the left was taken by me. Here is the company's version (there is some variation between sets, so the pictures sometimes show different variations of the samples):
Source: Max Whitby of RGB
Contributor: Max Whitby of RGB
Acquired: 25 January, 2003
Price: Donated
Size: 0.2"
Purity: 99.9%
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Sample from the Everest 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 (except gasses) weigh 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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Oxygen spray bottles.
I'm sure there's real oxygen in here, I just don't know why. Sure, breathing pure oxygen can be refreshing, if it doesn't make you dizzy, but a lightweight aerosol bottle like this can't contain enough to make any real difference. One of them also contains water which is probably more responsible for the refreshing effect than the oxygen, especially if the bottle is chilled, as they suggest, before you spray it in your face.
Source: eBay seller oxygeninc
Contributor: Theodore Gray
Acquired: 21 March, 2004
Price: $8/3
Size: 8"
Purity: 85%
Sample Group: Medical
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Aircraft emergency oxygen system.
This unit is designed to supply oxygen for about 5 minutes through a hood you put over your head. It could be a chemical oxygen generator or there could be a small high-pressure tank inside, I'm not sure which and I don't want to open the sealed pouch to find out.
Source: eBay seller rustnstuf
Contributor: Theodore Gray
Acquired: 23 March, 2004
Price: $20
Size: 9"
Purity: 90%
Sample Group: Medical
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Emergency oxygen tank.
I got this tank at the estate auction of a guy who had way too many tools. I'm not sure why he had this tank, but it did come with several hundred pounds of pressure still in it: Next time I'm feeling stressed I'll see if some pure oxygen helps.
Source: Auction
Contributor: Theodore Gray
Acquired: 6 November, 2004
Price: $2
Size: 12"
Purity: >90%
Sample Group: Medical
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  Portable oxygen tank.
This is a pair of empty oxygen tanks with regulator, probably intended for people who need supplemental oxygen, or maybe for paramedics to carry around.
Source: eBay seller waveles
Contributor: Theodore Gray
Acquired: 7 November, 2004
Price: $51.50
Size: 12"
Purity: >0%
Sample Group: Medical
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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.
This oxygen tube is not installed in the table, because it's so dim you couldn't really see it, and it's said to not last very long. So I just turned it on long enough to make the photographs (including a 360 degree rotation).
Source: Special Effects Neon
Contributor: Theodore Gray
Acquired: 22 November, 2002
Price: $35
Size: 2.5"
Purity: >90%
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Bowl of liquid oxygen.
Liquid oxygen is blue, beautiful sky blue (though the blue of the sky has nothing to do with the fact that oxygen in liquid form is blue). But it's not really quite this blue, except under certain viewing conditions. OK, I feel guilty, I admit it: The blue in this picture is slightly enhanced. But it really does look very blue, even this blue, when you're seeing it for example under a blue sky out of direct sunlight, or under certain kinds of lights, like the metal halide lights in my shop. I wanted to capture that amazing blueness for my periodic table poster, and I admit, I helped it a bit in photoshop. This is a shameful thing to do, and I'm sorry. (In case you're wondering, the only other samples in my poster that have had any color adjustment applied were gold and copper, which for some reason were just not looking gold or copper colored in print, even though the samples do very much so in person. In those cases, as in the case of oxygen, I tried to make the pictures look like the samples looked to me, even if that meant tweaking the colors compared to what strict application of the measured white balance would require. Color is a tricky thing, and sometimes you have to bend the rules to remove the lies the camera inserts.)
This sample to represents its element in my Photographic Periodic Table Poster. The sample photograph includes text exactly as it appears in the poster, which you are encouraged to buy a copy of.
Source: Claudin Welding Supply
Contributor: Theodore Gray
Acquired: 15 April, 2006
Price: $15
Size: 8"
Purity: 99%
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Aquamarine Beryl. (External Sample)
The metal beryllium is named after this mineral. I used to say here that beryl was named after beryllium, but reader Jeffrey Shallit kindly pointed out the absurdity of that notion, since the mineral was known and named long before the metal. He writes:The word beryl comes from ancient Greek and according to the OED, first appeared in English in 1305. But beryllium was not discovered until 1797 and the word "beryllium" did not appear in English until 1863. Beryllium the metal is fairly plain looking and toxic, while beryl the mineral is quite beautiful and comes in a great variety of shapes and colors.
Location: John Gray's Collection
Photographed: 11 March, 2003
Size: 3"
Composition: Be3Al2Si6O18
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Ruby. (External Sample)
Ruby, the name given to the red form of corundum, is just simply aluminum oxide. It's very hard: Common sandpaper is made with aluminum oxide grit. Artificial rubies are dirt cheap because they are easy to make. Natural rubies are very expensive because they are hard to find.
This specimen is natural, but not clear "gem quality" ruby, which of course makes it much less expensive.
Location: John Gray's Collection
Photographed: 11 March, 2003
Size: 3"
Composition: Al2O3
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Amber with bugs.
I picked this piece of amber out of literally thousands available at a big fossil show because it was really big, really cheap, and it had bugs in it. It's important to have bugs in your amber if you want to extract DNA and recreate dinosaurs, or impress the kids. I'm told that given the low cost this is probably "copal", not true amber, but hey, it's got bugs in it. Copal is much younger, only a few thousand years rather than potentially millions of years.
And it does have some really great bugs! Here's a close-up of one, which is about 1/4 inch in overall size:
I don't really know what the chemical composition of amber/copal is, but it's an organic resin which means it must contain carbon and hydrogen, and I figure it probably contains at least some oxygen, so I've listed it as being composed of those three elements, with carbon being the dominant one. Feel free to correct me if you know better.
Source: Time Trips
Contributor: Theodore Gray
Acquired: 29 March, 2003
Price: $45
Size: 5"
Composition: C10H16O
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Autunite.
I bought some Fiestaware plates from Jim to use in museum displays I'm helping coordinate, and he threw in this little sample of Autunite, a uranium mineral. He probably has Fiestaware available if you need some.
Source: Jim Markitell
Contributor: Jim Markitell
Acquired: 30 May, 2003
Price: Donated
Size: 1.5"
Composition: Ca(UO2)2(PO4)2.10H2O
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YAG boule top.
YAG stands for yttrium-aluminum-garnet: It's used to make lasers and can be doped with various elements to create different colors. This green one, for example, is doped with chromium.
The conical shape is similar to that of my silicon boule top, presumably because they are made by similar crystal-growing procedures. A crystal begins growing from a seed, expands out until it reaches the diameter of the melting pot is being pulled from, and then continues to grow as a straight-sided cylinder as it is pulled slowly out. Only the full-diameter portion of the rod can be used, so the cone at the start becomes waste and ends up with someone like me. (Actually, even this waste is quite valuable, probably because it can be melted down and reused. But Max found a nice company willing to sell us the cutoffs for a reasonable price.)
Source: Max Whitby of RGB
Contributor: Max Whitby of RGB
Acquired: 10 October, 2003
Price: Donated
Size: 2"
Composition: (Cr,Y)Al2O3
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Sapphire boule.
This is a "flame fusion" sapphire crystal boule, such as might be used to create synthetic cut gemstones. Flame fusion means a fine powder of aluminum oxide (the base material sapphires are made of) is blown through an extremely hot flame and onto a seed crystal. The molten droplets, somewhat amazingly, follow the pattern of the seed crystal and slowly accumulate into a large, single crystal of sapphire.
The slight pink cast in this boule comes from a 1% impurity of titanium. Impurities determine the colors of most gemstones, and are, for example, responsible for the difference between rubies and sapphires, both of which are made of aluminum oxide.
Source: SoCal (Nevada), Inc
Contributor: Theodore Gray
Acquired: 28 April, 2004
Price: $65
Size: 4"
Composition: Al2O3+Ti
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Autunite.
Autunite, if it is not kept in a humid environment, tends to degrade due to loss of water from the crystal matrix (see formula below, which indicates there are 10 molecules of water associated with each atom of uranium). This sample flaked apart as I was trying to mount it for photography, dropping little leaves of radioactivity everywhere. Still, quite pretty.
Source: eBay seller dr**zarkoff
Contributor: Theodore Gray
Acquired: 10 June, 2005
Price: $15
Size: 0.5"
Composition: Ca(UO2)2(PO4)2.10H2O
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Thorite.
This is a very rare thorium mineral. Not much to look at, but it has a well-defined crystal structure and it's hot enough that when it fell under a bunch of stuff, I had no trouble locating it with a Geiger counter. (This is one of the great advantages of radioactive things: You can never really loose them. Not so the osmium pellet I'm probably never going to find.)
The price reflects the rarity of this species.
Source: eBay seller mineralman999
Contributor: Theodore Gray
Acquired: 3 June, 2005
Price: $90
Size: 0.5"
Composition: (Th,U)SiO
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Torbernite.
Torbernite is a lovely, lovely green color (I would guess from the copper). It's also quite radioactive, from the uranium content, and even more so from the mixture of uranium decay products that have built up in it over millions of years.
Source: eBay seller migalf1
Contributor: Theodore Gray
Acquired: 3 June, 2005
Price: $27
Size: 1.5"
Composition: Cu(UO2)2(PO4)2.8-12H2O
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Carnotite.
The yellow crust is the carnotite, an ore of uranium that also contains some traces of radium, which is used to justify the name "Radium Ore Revigator" used to describe the water jug you'll find listed under uranium (and which is lined with carnotite).
Source: eBay seller dr**zarkoff
Contributor: Theodore Gray
Acquired: 3 June, 2005
Price: $15
Size: 1.5"
Composition: K2(UO2)2(VO4)2.3H2O
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Autunite.
This autunite was donated by the mine owner who dug it up: It's a lovely specimen, photographed here under ultraviolet light. You can get samples of this an other radioactive minerals direct from the mine.
Source: eBay seller boomologist
Contributor: Theodore Gray
Acquired: 25 June, 2005
Price: Donated
Size: 1.5"
Composition: Ca(UO2)2(PO4)2.10H2O
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