How different pressures of air force water from a container
Fit a test tube with a two-hole stopper. By one hole place a length of glass tube which extends into the test tube almost to the bottom. Put water in the test tube and suck on the upper end of the glass tube. View what happens. Next tightly close the open hole in the rubber stopper and again suck on the glass tube. View what happens. How do you account for the dissimilarity?