From what I understand about how pipettes work (correct me if I am wrong), when you squeeze the bulb of a pipette, you are removing the air from it and when you dip the end in liquid and release the bulb, the area increases so the pressure in the bulb drops. So due to the atmospheric pressure pushing down on the liquid surface outside the pipette and not having an equal pressure pushing down inside the pipette, the liquid rises into the pipette until the area in the bulb gives an equal pressure to atmospheric pressure.
However, I don't understand how the liquid stays in the pipette once you raise it out of the liquid and doesn't fall out until you squeeze the bulb again. It seems like the liquid should be heavy enough to fall out? Is it due to intermolecular forces holding the liquid there?