|MadSci Network: Engineering|
Dear Louanna, You are quite right with your contention that there are big drops and little drops. (I'm not discussing drops sitting on a surface here - that's even more complicated) The size of a drop depends not only on properties intrinsic to the liquid at hand (surface/interface tension, density) but also on its adhesion to the rim of the dropper or other orifice from which it emerges. If an injection needle is used, this tends to yield smaller drops than a medicine dropper. Most drops are generated under dynamic conditions (i.e. ejected more or less violently). This causes premature detachment from the nozzle. Drops as small as 3 picoliters (millionths of a microliter) can thus be generated by the printhead of an ink jet printer. On the other end, out in gravity-free space, drops of unlimited size are theoretically possible, if you spend enough time growing them. Best Regards Werner Sieber P.S. I have tried severel times to answer this question since June, but the line was apparently down.
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