Pure nitrogen weighs just slightly less than air, so wouldn’t readily float a balloon. Methane is lighter than air but not by that much and would require much larger balloons and is also flammable. Hydrogen could be used but as you say people immediately think of the Hindenburg. But during WWI the Germans bombed London from zeppelins and the Brits found it very difficult to bring them down using incendiary bullets. The hydrogen under low pressure did not mix readily with air and was very difficult to ignite. A biplane firing a machine gun mounted straight up had to make repeated passes under a zeppelin firing specially designed incendiary bullets into the same location in order to ignite the hydrogen. The accidental ignition/combustible paint theory of the Hindenburg really doesn’t hold up in comparison.
Hot air is also lighter than less hot air. It’s not practical for party balloons but something could be worked out for parade balloons.
All above gases except Neon has problems with flammability or nastiness. Neon has about 2/3 the density of air, so the balloon has to be extremely light for it to work.
Now steam is lighter than air, so if the room temperature is above 212F, steam balloons will work, but that’s a very very hot party.
Probably the biggest waste of helium is simply burning natural gas. Most natural gas deposits have some helium in them. Some have enough helium to make it economical to separate, most times it isn’t, so the helium comes along with the methane to the consumer, and goes straight up the flue. LNG plants make it easier to recover the helium, as you get the fractionation essentially for free as you liquefy the methane. But piping the gas directly to the consumer typically just wastes it.
Yes. The only source sufficient for the Germans to fill their Zeppelins was from the US and the US refused to sell it to them so they used hydrogen.
Hydrogen was flammable but also it had greater lifting power than helium so it wasn’t all bad.
And remember, hydrogen needs oxygen to burn. I had long wondered why blimps didn’t burst into flames at the fist shot from an enemy aircraft but, apparently, they were a lot more resilient against that then one might suppose. Which is to say they weren’t quite the flying bomb you’d think they would be.
As described above, the hard part of any Fuel-Air Explosive is getting the mixture dilute enough to ignite & stay burning uniformly enough to give the desired big bang.
Outside the envelope there’s way too little fuel and way too much air (oxygen really). Inside the envelope it’s the opposite. If you magick away the envelope and wait a bit, diffusion (& wind) will produce regions with mixtures in the combustible range. But then you’ve got to put your igniter(s) where those region(s) are.
OTOH …
When I was a kid we had great fun filling ordinary elastic party balloons with acetylene from our welding tanks. Then we rigged an electric igniter using a suicide cord connected to some fine copper wire (stripped telephone hookup wire worked great) wrapped around the base of the inflated balloon.
Plug it in, hear the brief humming surge of electricity through the wires, followed by a very smoky sooty FOOF! as it went off. Even better to put some oxygen in there along with the pure acetylene. The BANG! when you got the mixture just right was impressive to say the least. We laughed until we peed our pants on more than one occasion.
I do not recommend that any tweens reading this try this at home unless you’re already pretty experienced at dangerous Mythbusters-style experiments. And even then, better not to.
As to any grown-ups, just be sure to yell the secret code words before plugging in. No, that’s not “Fire in the hole!”. It’s “Hey y’all! Watch this!”
Perhaps a mixture of hydrogen helium and maybe some nitrogen and or neon mixed in could be used for lifting purposes, limiting the ignitability of the hydrogen by dilution and not using as much helium as if one was filling to straight up?
When was it ordained that all party balloons must float, which meant being filled with helium? As a child we just blew them up with lung power and filled them with whatever nasty gases a kid has inside them. The balloons kind of floated which was good enough for us.
BTW, another reason not to use party balloons, especially the mylar ones, is environmental consequences. Yet more litter, basically, unless you collect them after using them, rather than letting them float off towards the horizon. Fat chance. They can entangle wildlife, and contribute to the plastics floating around in the oceans. Latex does eventually degrade, which is why the mylar ones are worse, but it still takes a while.
This may actually be a better reason to forgo the party balloons. US helium consumption has dropped about 20% since 2010, and I suspect that reflects better recovery from non-lifting applications, party balloons or no party balloons.
Weather balloons, btw, are launched at the rate of something in the vicinity of a couple thousand every day world wide. We can probably accept that, given that a useful purpose is being served. And, as noted, those can be filled with hydrogen, although that still means they contribute to the litter problem.
In air, below a 4% concentration by weight there’s not enough hydrogen to burn, it’s below the Lower Explosive Limit (LEL). Again in air; if the hydrogen concentration is above 75% by weight it won’t burn either, there’s not enough oxygen to support combustion, it’s above the Upper Explosive Limit (UEL). You could fill party balloons with a 96/4% nitrogen/hydrogen mixture.
That’s probably not light enough to float a party balloon reliably, but you could enrich the ambient atmosphere with argon. It’s almost one and a half times the density of air and it’s the third most abundant element in air. It’s much more easily recovered than helium.
Sure, it sounds crazy, but if you don’t think about it too much it might work.
Why not go with sulfur hexafluoride in that case? It’s non-toxic and made from common elements. You could have really floaty balloons in that case. Just make sure to keep a fan going to keep the air well-mixed. Oh, and I suppose it is over 4 orders of magnitude more potent than CO2 as a greenhouse gas, so keep it indoors.
As a bonus, it also makes everyone sound like Barry White.
There’s an oft-quoted figure out there by the US Dept of the Interior in 2014 that the world helium supply was enough for 117 years. In the US, we have something on the order of 20 to 30 years readily available. New deposits have been discovered in Tanzania which may be enormous.
