Science with Richard Bleil
At a dollar store today, I was looking at the balloons. I’m too much of a chemist, and felt compelled to tell the person working behind the counter that helium does not leak out through the tie in the bottom of the balloon. In reality, the helium is so very small that it diffuses through the rubber walls, simply finding its way out between the molecules of the rubber itself. This is why clips and double knotting is double nonsense. Mylar balloons, on the other hand, are similar in their structure to metal in that there is a coating of electrons on the outside of the material. This is why Mylar, like metals, is shiny. Those electrons reflect incoming light. The layer of electrons act to “plug” those little holes since electrons are smaller than helium.
It’s basically a bit of trivia, although in some views, this entire post is likely to be trivia.
Helium is an element. Unlike compounds that contain at least two different elements in a fixed whole number ratio (like water contains the element hydrogen and oxygen at a 2:1 ratio). Compounds can be separated from each other in compounds. For example, electrolysis will separate water into the individual hydrogen and oxygen. Elements, on the other hand, are as simple as they can be. They cannot be further broken down by regular chemical means (maybe nuclear).
This has interesting implications for helium. You cannot make new helium, so the world supply of helium is fixed (more or less; it is released in certain nuclear decay processes). During World War II, helium was only present in great quantities in two countries, the United States and Russia. It is found in caves, and after Germany’s war with Russia began but before America joined the conflict, Germany built the Hindenburg as Nazi propaganda. Of course Russia wouldn’t sell helium to Germany, and although America was not at that time at war, it stood opposed to the Nazi expansionism and refused to sell helium as well. As such, Germany was forced to fill the Hindenburg with highly flammable hydrogen. The US had come to an agreement to sell Germany the helium needed for the airship, and it had flown across the Atlantic to be retrofitted with the inert (non-flammable and non-explosive) helium when, on touchdown, a spark ignited the hydrogen leading to the Hindenburg disaster.
Because helium cannot be made, the world supply is finite. The pockets of helium in Russia and the US were quite large and assumed to be infinite, but along with serious applications, it has become a source of great entertainment. As its use has increased, it was looking as if we would run short of the precious gas. At one point it was estimated that we would run out in about 20 years. That estimate put depletion at 2010, and yet, here we are, filling balloons with helium. Fortunately, a third deposit was located, and the amount of helium available is again so excessive that it is considered to be infinitely available (much like we act as if we will never run out of oil).
Scientifically, helium is used in several ways, two of the major ways being as an inert atmosphere and the other in instruments such as gas chromatographs used in analytical chemistry. An inert atmosphere means that it is used so that oxygen cannot enter the reaction vessels. Some chemicals are highly reactive, and oxygen will destroy the chemists’ products on contact. If the reaction vessel is filled with helium (which is non-reactive so it will not destroy the products). It’s this same lack of reactivity that it’s used in instruments like gas chromatographs. But fear not, chemists will be fine. I was reading an article in a very well-known and respected news source that claims that helium is “the only non-renewable resource in the world.” This is wrong. Every noble gas is the same way; neon (used in neon lights), argon (the third most common element in air), krypton and so forth are all non-renewable because they do not occur in compounds. Oh, sure, they’ve all been FORCED to be in compounds by cruel evil chemists, but the amount of these compounds is insignificant.
Helium, on the other hand, is the only element on the periodic chart that has yet to accept the terms of being a part of a compound. No matter what chemists do, no helium compounds have ever been made. What’s more, it’s the only element that has never solidified. Helium does condense into liquids (at roughly 458 degrees Fahrenheit BELOW zero), but it has yet to be forced into a solid form. What a fascinating and unique element.
Bleil's Banter 