Inches of Mercury (inHg) – An Imperial Unit for Pressure
Theinches of mercury (inHg)is an imperial unit of pressure often used in aviation and meteorology. It measures the height of a mercury column in inches and is particularly useful for describing atmospheric pressure.
History & Background
Developed during the era of mercury barometers, inHg has been used for over a century to quantify atmospheric pressure. It remains popular in countries that use the imperial system, especially in weather reporting and aircraft instrumentation.
Conversion Factors
- 1 inHg ≈ 3386.39 Pa
- 1 inHg ≈ 3.38639 kPa
- 1 inHg ≈ 0.0338639 bar
- 1 inHg ≈ 0.491154 atm
Applications
Inches of mercury are used to report barometric pressure in weather forecasts and to monitor cabin pressure in aircraft, ensuring safe and efficient flight operations.
Interesting Facts
Many pilots and meteorologists are accustomed to reading inHg values when assessing weather conditions and atmospheric pressure.
Conclusion
Inches of mercury provide an accessible, imperial-based measure of pressure that is especially valuable in aviation and weather forecasting.
Millimeters of Mercury (mmHg) – Common in Medicine and Meteorology
Themillimeter of mercury (mmHg)is a unit of pressure based on the height of a mercury column. It is commonly used in medical contexts, particularly for measuring blood pressure, and in meteorology for atmospheric pressure.
History & Background
The mmHg became popular when mercury barometers were used to measure atmospheric pressure. Its continued use in medicine and meteorology attests to its practicality and historical significance.
Conversion Factors
- 1 mmHg ≈ 133.322 Pa
- 1 mmHg ≈ 0.133322 kPa
- 1 mmHg ≈ 0.00131579 atm
Applications
mmHg is used to monitor blood pressure, calibrate barometric readings, and analyze pressure changes in various scientific fields.
Interesting Facts
Normal human blood pressure is often cited in mmHg (e.g., 120/80 mmHg), making this unit familiar to healthcare professionals and patients alike.
Conclusion
Millimeters of mercury continue to be a vital unit in medicine and atmospheric sciences, providing a direct and understandable measure of pressure.