Communicating vessels with four containers - quiz: "Which tank will be full first?"

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In November 2016, for the first time, social networks began to spread the problem with the question: "Which tank will be full first?" Various responses have appeared and are still in the discussion. Often, in the course of dialogue with students, their misconceptions are based on misconceptions in understanding the issue of communicating vessels. All printed parts behave like a translucent optical environment through which light passes partially, but also scatters during passage. The liquid is better visible after staining with the food dye. The correct answer to the original question is that the fourth and third vessels are filled simultaneously (a container filled with liquid at the top of the container is considered a full tank). Communicating vessels is a name given to a set of containers containing a homogeneous fluid connected to the base and subjected to the same atmospheric pressure. When the liquid sets, it balances out to the same level in all the containers, regardless of their shape and volume. If liquid is added to one vessel, the liquid will again find a new equal level in all the connected vessels. The selected sizes of the coupled vessels are almost borderline, with smaller dimensions, other physical phenomena would be involved in fluid behavior. Capillary elevations or capillary depression may also occur with a small and different diameter of vessels or their connections. This phenomenon is significant when it comes to vessels with a diameter in the order of millimeters or less. The filling of the top container should be done with a syringe sufficiently slowly, ideally in the hood as shown on the original instructions. An important condition is the immobility of liquids, the fluid pressures in different containers may vary due to Bernoulli's phenomenon.