Very true. I guess I was more worried that so far ordinary superconducting magnets (i.e for NMR and MRI devices) are not viable with these materials. Given another 100 years of research it is probable that this will be solved. Heck we might even see a room temperature superconductor by then. OTOH, it is hard to believe that there won’t be lots more really important physics down at liquid helium temperatures found in that time too.
Nitpick: it wasn’t thermite. Right ingredients, wrong ratio.
John Carter of Barsoom often ran out of Helium, usually with the incomparable Dejah Thorus at his side.
Note that in the last few years, we’ve been paying more attention to recovering helium after use, rather than allowing it to escape into the atmosphere. That should help. For instance, the Macy’s day parade now recovers the helium from their balloons - they used to just empty them. Of course, that’s pretty much symbolic, as lifting applications, including weather balloons and so on, as well as party balloons, are only a small fraction of the usage.
Thanks for all the great responses. Seems as though we really could run out of helium and most certainly will run out of economical helium. I also learned that conservation in the form of recovery after use is beginning to happen. I read elsewhere that shortages of helium made Valentine’s Day balloons much more expensive last February.
How safe would hydrogen be for children’s balloons? How easy would it be for a kid with a match to hurt himself?
It’ll remove the kid’s eyebrows but it won’t kill anyone:
A balloon with a stochiometric mix of hydrogen and oxygen makes a much bigger bang, and could probably rupture eardrums:
Does released helium float up, or just mix?
It’s an inert gas, so there aren’t any known compounds (and not for a lack of trying). Gravity doesn’t have much of a hold on it, so it’s lost to space.
It may be elusive here on earth, but next to hydrogen, it’s the 2nd most abundant element in the universe.
I remember watching Mr. Wizard as a kid popping a hydrogen balloon with a match. The reaction with the oxygen in the air produced a small droplet of water you could see flying away in slow motion.
A few episodes later he inspired me to build a miniature hot air balloon, that’s the one I lost my eyebrows on. Really.
Note that under some conditions noble gasses can form compounds
Brian
Lost to space? So it can escape Earth’s gravitational pull? I thought gases, being quite ideal, would mix (like an ideal solution). I wonder how much density difference is required before mixing doesn’t happen.
Helium isn’t explosive. You’re thinking of hydrogen.
Much helium DOES eventually escape into space, but some is present in the atmosphere also. Wiki gives a figure of 5.24 ppm by volume, which sounds about right:
That puts it in the middle of the pack for noble gasses - argon and neon are present in greater percentage by volume, xenon and krypton less. radon, too low to make that list (not surprising, as it’s radioactive with a fairly short half life).
I believe, helium, being very low in density and also totally inert in anything other than extreme and forced conditions, won’t really mix well with the open air. The atoms will just continue to rise, due to it’s low density, and depending on the temperature, the atoms will zip around much faster than heavier ones that are far more abundant (obviously molecular nitrogen and oxygen [ N[sub]2[/sub] & O[sub]2[/sub] ] and other compounds like water and CO2), until finally reaching the escape velocity of the earth.
There are other factors too, like the solar wind and such, but basically, the lighter elements, over time, just sort of evaporate into space.
Helium, like any other gas, will mix in the atmosphere. All gases in the atmosphere get lost to space; helium just gets lost more quickly, due to its low molecular mass. With nitrogen and oxygen, the loss is too slow to notice.
Heh. I see what you did there.
The ideal gas law states that at a given volume and temperature, any gas will exert the same pressure on its container. Considering that “pressure” is an average of the gas molecules hitting stuff, this means that the lower the mass of the gas molecules, the higher its speed. Helium is so light that at standard earth conditions the average velocity of a helium atom is greater than the escape velocity required to escape Earth’s gravity well, and so they leak into space quickly.
Bravo! Bravo!
I, for one, remain unconvinced as sure as I am the sun will rise tomorrow.