Helium and Hydrogen lifting power?
If a balloon filled with Helium could lift a 1.0 lb. weight, How much weight would the same sized balloon be able to lift, if it were filled with the same amount of Hydrogen instead?
OK...I need more answers. So far I got 8% and 400%. What is the real answer here? Anyone know for sure?
- jaz_willLv 51 decade ago
Lifting power comes from buoyancy. Buoyancy comes from volume.
Suppose a balloon filled with helium can lift a 1lb = 454g weight. The total force on the balloon in equilibrium is
0 = B - G - 454g
where B is the buoyant force and G is gravity on the balloon itself. For argument sake, suppose the balloon weighs nothing. (I am also suppressing in the equation all irrelevant factors of the gravitational constant.) B is equal to the weight of the displaced air. At 1 ATM, it is roughly 28.8 grams per 22.4 litres. The mass of helium inside of the balloon is roughly 4 grams per 22.4 litres. Taking the difference gives roughly 25 grams of lifting power per 22.4 litres.
The same calculation done for hydrogen (gas, H2) gives 2 grams per 22.4 litres mass, and hence a lifting power of roughly 27 grams per 22.4 litres.
Further assuming that hydrogen and helium gas approximate the ideal gas equation sufficiently
pV = nRT
then the same amount (moles, not the same weight) of hydrogen at the same atmospheric pressure should displace the same volume, so the lifting power of hydrogen is roughly
(27 - 25)/25 = 8%
more than helium. So you should be able to lift 1.08 lb with hydrogen balloon.
- Anonymous1 decade ago
(1H1) v (2He4) would indicate that helium is 4X heavier than hydrogen. This should imply that if He can lift1, H should lift 4.