Talk:Getting Started/@comment-67.166.119.94-20140728051453

Correction on your gas selection. Hydrogen provides a SMALL increase in lift, but no where near double. The reason is that lift is caused by the weight of the gas DISPLACED which is air, no matter what gas you use to fill the balloon. The NET lift is the difference in weight between the gas displaced (air) and the lift gas filling the volume (H or He). The molecular weight of air is pretty close to 29 g/mol. The molar weight of H2 = 2 g/mol and He is 4 g/mol.

Thus, net lift is 29-2 = 27 g/mol for hydrogen and 29-4 = 25 g/mol for helium.

Hence, the difference in lift is fairly small. You get 8% more lift with hydrogen. Clearly, that is not even close to twice the lift.