Here’s the one I saw demonstrated in my 8th grade science class:
Fill a small bucket with CO[sub]2[/sub] gas. It’s invisible, so you just have to take it on faith that the CO[sub]2[/sub] will just sit there in the bucket, and not instantly completely dissipate.
Now, light a candle. Hold the bucket about a foot above the candle, and pour the CO[sub]2[/sub] out of the bucket. The candle will go out, thus demonstrating that you can pour CO[sub]2[/sub] through air.
Just a little safe-n-sane demo of the Lake Nyos incident.
Sulfur Hexafluoride is heavier than xenon, and about the densest gas that’s inert enough that you’d want to play with it. There are things like tungsten hexafluoride that are heavier but god-awful reactive with air, water and chemistry teachers.
If you want to up the temperature some (168 F), xenon hexafluoride is quite the heavy gas with a molecular weight of 245. I’m guessing a balloon filled with that would hit the floor pretty quickly.
In Israel during Gulf I (Scuds from Iraq War), the entire populace learned something about heavier-than-air gas, most of whom never gave the matter much thought beforehand, I’m guessing.
It became Topic A in that, by all common sense and proved by experience, War/Missiles=head for bomb shelter. But everyone was lectured over and over again that whatever anticipated gas released from the Scuds would sink. So ixnay on the shelters. It was all the more unnerving to be sitting ducks that way.
Towards the end of the war rumors got out that high defense staff were saying Fuck this, I’m staying in the shelter, and people started following suit. Hell, that’s when Scud versus Patriot viewing parties were going on.
It must take quite some laboratory trickery to create xenon hexafluoride, xenon being an inert gas. I know some inert gases can be coaxed into molecules with other atoms by sufficiently contrived laboratory procedures. But it this possible with the heavier inert gases, or only with the lighter ones? And are such compounds stable, or do they decompose promptly?
There appears to be more compounds with the heavier noble gases than the lighter ones. There are none for helium or neon. As I recall (and my link probably talks about this but I haven’t read all of it), they are quite difficult to make but once made, they’re very stable.
As to the rest, I’m guessing exhaling normally would clear the lungs enough to allow normal breathing, but the headstand is to ensure that all the xenon is gone.
But I don’t think it is necessary. Probably not even helpful. Gases in the lungs mix pretty well with every breath, so any xenon in your lungs should be quickly diluted and expelled, assuming you’re breathing normal air again.
In this thread I linked to in that previous discussion here, Bored Chemist links to this MRI image of xenon in lungs, which shows that the xenon is evenly distributed throughout the lungs.
That’s a really neat way to demo it. The less dramatic way was to pour it over a lit candle to put it out. Seeing it as a boundary layer of gas makes it stand out.
“Mom, my chemistry teacher inhaled this heavy gas that made his voice sound really deep.”
vs.
“Mom, my chemistry teacher inhaled this heavy gas that made his voice sound really deep, and then he had to stand on his head to exhale all the gas so he wouldn’t die!”
Understood - my point was that even if it didn’t work this way, your lungs wouldn’t be full of xenon after breathing out once, and any reduced lung capacity would be a nuisance rather than life threatening.
Interesting to note, while I was looking up how expensive this stunt might be (xenon being pretty scarce stuff) that xenon’s actually an effective anaesthetic, and not merely an asphyxiant. That’s kinda counter-intuitive for a noble gas.
No - there’s about two orders of magnitude difference between liquid densities and gas densities (at standard temperature and pressure); that is, you’re weighing liquids in hundreds of grams per litre, minimum, and gases in grams per litre.
not a planet, but on titan the air is a lot denser than on earth, so any balloons would float up (and the gravity is a lot lighter too, so you could conceivably float using a bunch of earth air balloons)
the venusian atmosphere is a lot denser too, but the balloons would probably cause the air to combust and/or be crushed by pressure
pretty much the same thing on jupiter/saturn/neptune/uranus below certain altitudes