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A cheap way to realize low pressure differences (and a method that is nearly unbeatable for smoothness) is gravity. Fill everything with liquid, run input and outlet tubes to two beakers/buckets/etc, with the one on the input side be higher than the output. Approximately 1 mbar per centimeter height difference for water at room temp.


This is a challenging measurement. In my opinion best done with a very good balance. Fully shielded from thermals and vibration, obviously. Use a small container with small opening diameter to limit evap to what will hopefully be under 10% of the final measurement (and we will correct for it more later). A clean 2mL glass bottle is good. Fill bottle halfway, ...


Same answer as above, "Yes BUT..." This is from a practical point of view: Other than HPLC, nearly all "microfluidics" applications are far into the laminar region. Poiseuille's law works very well most of the time. When going below 100$\mu$m dimensions, the problems come. lack of stiffness -> violates assumption that fluid into a ...

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