|MadSci Network: Physics|
Hi, Surely I am mad enough, but I am not a scientist so I really need to hear your opinion. If I put small amount of heavy water into a cup of normal water – two things can happen: a) Heavy water molecules can spread uniformly b) Due to gravitation force, there will be slightly more heavy water molecules near the bottom of the cup than near the top (difference probably not measurable) If the answer is a) then read no further. Instead of putting heavy water I could dissolve some sugar into the water. Again, will sugar molecules spread uniformly or not? If the answer is ‘not’ then read no further. Is there any molecule bigger than water molecule that, when dissolved in water, will make measurable difference in concentration near the top and the bottom of water cup due to gravitation force (or, maybe, strong centrifugal force)? If such molecule exist then I have a problem… Imagine a small closed box fully filled with such water solution. The top and bottom sides of the box are semi- permeable membranes (permits water molecules but not our big molecule). We put the box into the water. Due to difference in concentration at the top and at the bottom of the box there will be difference in osmotic pressure (?) that will cause perpetual motion of the water (?!). You see now why I am mad ;).
Re: How gravitation effects molecule distribution in solutions
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