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Why mercury stays up
publish date: 2026/05/19 19:27:56.063229 UTC
volume_mute
In a mercury barometer, what force or phenomenon keeps the mercury from simply draining completely out of the inverted tube?
Correct Answer
Atmospheric pressure pushing down on the mercury pool below
Explanation
The atmosphere pushes down on the surface of the mercury pool in the open container. This pressure is transmitted through the liquid and pushes the mercury up into the inverted tube. The column of mercury rises until the pressure exerted by its weight equals the atmospheric pressure pushing down on the pool.
Reference
Basic Physics: A Self-Teaching Guide