I have a few questions....
1. Is Helium the lightest inert gas?
2. If not what is the lightest inert gas?
3. If so, then how much weight can 1 cubic foot of Helium keep afloat without sinking below the surface?
4. Since fresh water and salt water have different characteristics, what is the difference in the amount of weight that can be kept afloat with the same 1 cubic foot of helium?
IE: If 1 cubic foot of helium can keep 5 lbs afloat in fresh water, how many pounds can it keep afloat in salt water?
5. How many cubic feet of Helium are compressed into each of the standard sized Gas bottles?
Any help is greatly appreciated