Instruments

Barometer

Citation Formats

General Reference

Science Atlas. "Barometer." Accessed August 30, 2026. https://science.interactiveatlas.org/instruments/barometer.

APA Style

Science Atlas. (n.d.). Barometer. Retrieved August 30, 2026, from https://science.interactiveatlas.org/instruments/barometer

BibTeX

@misc{scienceatlas-barometer,
  author = {Science Atlas},
  title = {Barometer},
  year = {2026},
  url = {https://science.interactiveatlas.org/instruments/barometer},
  note = {Accessed August 30, 2026}
}

A barometer measures atmospheric pressure. Evangelista Torricelli built the first mercury barometer in 1643-44, filling a glass tube with mercury and inverting it into a dish, and correctly concluded that the changing height of the mercury column tracked changes in the weight of the air above it.

Facts

Invented Year

1643 1

Measures

Atmospheric pressure. 2

Operating Principle

A column of mercury in a sealed tube is balanced against the weight of the atmosphere pressing on an open mercury reservoir, so the mercury column rises and falls as air pressure changes. 2

Operating Range

Average atmospheric pressure varies between about 940 and 1040 hectopascals (millibars) at sea level; mercury barometers typically read between about 670 and 800 millimeters of mercury. 2

Open Questions

Resolution

Not stated as a numeric figure in the cited source.

No explicit resolution or precision figure is given by the cited source for the barometer.

Cross-Tradition Connections