: Here is another set up to jog your intuition. I have some connected volumes of various odd-ball shapes. I fill the containers and find that irrespective of the specific shapes, I get equal levels of water as long as the tubes are connected. The reason for this is that pressure must be the same where the liquids meet. To achieve this the vertical height of the water column above the common point must be identical. If you understand this well and also are handy with soft solder you may have a future as a plumber.