Does Methane Gravitationally Differentiate in Air or Mix with Fluid Dynamics?

[Praestrigiator]

Does methane gravitationally differentiate in air, or does fluid dynamics mess things up & make it mix in with the air?

 

[mathman]

Does methane gravitationally differentiate in air, or does fluid dynamics mess things up & make it mix in with the air?

Both. Methane has molecular wt. approx. 16, while oxygen and nitrogen have molecular wts. of 32 and 28, so the methane would slowly rise when the air is perfectly still. However the air is never perfectly still, so wind,etc. tends to mix things up.