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. With the exception of chlorine and bromine they all look exactly the same: Like nothing at all. In some ways, gases are a pain from a sample point of view. 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.īy the way, isn't it a cute oxymoron: Reagent-grade non-reactive gas. 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. The others almost certainly failed because the type and pressure of gas in them does not support an arc, not because they are empty. Whether this is possible is sensitive to the pressure of the gas, which is not known.įortunately, it worked beautifully on three out of the five, and proved beyond a reasonable doubt that those three at least contain the gas claimed. 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.Īfter many unworkable suggestions for proving whether the gases 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. There's no visible way for the gas to have escaped. 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.
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".
#Helium periodic table plus
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).
They are thin-walled steel, not like the heavy gas cylinders used in welding, and only contain enough helium for about 30 balloons. You can buy these lightweight tanks of helium at Walmart or any party supply store. (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.) It's used as an inert shield gas to protect things from oxidation. Helium is a noble gas, which means it doesn't react with anything for all practical intents and purposes. 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. 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). (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. Helium is the second most common element in the universe, representing about 10% of the total matter. My periodic table poster is now available!
Facts, pictures, stories about the element Helium in the Periodic Table
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