Say I have some volume V of some gas with a pensity P less than the density of air. How can I calculate how much a balloon (of volume V) of this gas could lift? Is this called the "buoyant" force, or is this something else? What I'd like to do is find the find the lifting "power" (...) of some volume of helium, or the upward force in the fluid of air that a volume of helium could exert. How much of a gas would I need to pack into a container in order to lift some mass up some distance, etc. Is there a branch of physics these sorts of questions neatly fit under, BTW, that would help my search for information? I remember a strange attribute of my first three physics class, which were supposed to provide a solid introduction to all physics (minus quantum) was the complete lack of discussion on things like hydrostatics and buoyancy... Thank you, sorry for the simplicity of these questions!