Why does water vapour not fall down to earth because of gravitational force?
Water vapouris a gas. One molecule of water contains two atoms of hydrogen and one of oxygen. Chemists would say its molecular weight is 2+16 = 18. Molecular weight of nitrogen is 14+14 = 28 and that of oxygen it is 16 +16 = 32. Therefore you see that air that consists mostly of nitrogen and oxygen is significantly heavier than water vapour. This is what makes water vapour rise in the atmosphere. And this is the reason we have clouds and rain. Rain clouds are not all water vapour. They also have tiny drops of condensed water. When the water droplets are very tiny we have fog. That floats around in valleys between hills. So in answer to your question one can say that the water contained in water vapour does fall down because of gravitational force but only after the vapour condenses into liquid form. Then we call it rain. How is it determined as to which is the best place to look for oil? I think the first step would be look for a gravitational anomaly. If there is a large bubble of oil
