> In fact, if you asked me to produce a kilogram of hydrogen I don't know what I would do. Is it buoyancy? do you want -1 kilo of the stuff? Nerd sniped. Atmos

> In fact, if you asked me to produce a kilogram of hydrogen I don't know what I would do. Is it buoyancy? do you want -1 kilo of the stuff? Nerd sniped. Atmosphere is 1.2 kg/m^3, hydrogen is 0.090 kg/m^3. So 1 kg of hydrogen at STP would be 11 m^3. The buoyancy force would then be 13kg-1kg. Accordingly, 1kg of H weighs -12kg.