I don’t know if I ever asked this before, excuse me if I did.
Poke a puffer fish and it’ll puff by filling its belly with water, growing a few times its size and getting into a more round shape.
Now, suppose you make an experiment in some way that it swallows helium instead of water. I don’t know, maybe a hose connected to its mouth or something. The question is, would the cause the subject to float out of the water and into the air? And if so, would controlled flight be possible by this manner?
the fish wouldn’t survive being filled with helium. And it depends on how heavy the fish is and how much helium you could put inside it. Obviously it has a limited amount of space with which to insert helium. Any control mechanisms would add to the weight and so. No. You couldn’t do what you’re suggesting.
Adult puffer fish weigh 20 to 30 pounds (9 to 13.5 kg).
Good size normal balloon has about 10-15 Liter volume.
Helium has 0.1786g / L density, Air has 1.292g / L.
Difference is the lifting force, 1.292-0.1786 = 1.113 g / L.
Figure 12.5 Liters x 1.113 g / L = about 14 grams.
454 grams / pound divided by 14 = about 32 balloons.
So, to lift a pound, you would need about 30-35 good size ‘normal’ balloons.
But that’s like a fish with water and guts inside. If you hollow the fish out, and put in a helium balloon, and inflate the balloon, you might be able to do it… I dunno… It would be difficult. and you could add like a toy helicopter it might give enough lift.
No, I really thought it would be a biology question, mostly because I was thinking about keeping the fish alive (I think it would still be able to breath on air, given we keep its gills moist), but the impossibility of making it fly has kinda made me sad now =\
History question now: back when people were quitting their nomadic lives for the first time in pre-history and settling down, when man milked a cow for the 1st time - WTF was he thinking?