volume_mute
Mercury barometer diagram analysis
publish date: 2026/05/19 19:27:55.526937 UTC
volume_mute
Based on the description of a mercury barometer, what occupies the space at the top of the sealed tube above the mercury column?
Correct Answer
A vacuum (very low pressure)
Explanation
When the mercury-filled tube is inverted into the pool of mercury, the mercury falls, leaving a vacuum (called a Torricellian vacuum) at the top of the tube. This empty space is what allows the atmospheric pressure pushing on the mercury pool to support the column of mercury.
Reference
Basic Physics: A Self-Teaching Guide