Why is it not possible to measure absolute vacuum or absolute pressures using barometers, which are based on atmospheric pressures?
Barometers, which are designed to measure atmospheric pressure, can’t measure absolute vacuum or absolute pressures due to their reliance on atmospheric conditions.
Barometers are great for measuring atmospheric pressure, but they fall short when it comes to measuring absolute vacuum or absolute pressures. Here’s why:
- Dependent on Atmospheric Pressure: Barometers work by measuring the pressure exerted by the atmosphere. They compare this pressure to a vacuum inside the barometer. Since they rely on the weight of the air above them, they can’t measure a true vacuum where there’s no air to exert pressure.
- Design Limitations: Barometers are calibrated based on standard atmospheric pressure at sea level (101.3 kPa). They aren’t designed to handle the extremely low pressures of a vacuum or the variations in absolute pressure that extend far beyond the atmospheric range.
- Accuracy Issues: For absolute pressure measurements, you need an instrument that can measure pressure in a completely air-free environment. Barometers can’t do this accurately because their readings are influenced by the presence and weight of atmospheric gases.
To measure absolute vacuum or absolute pressures accurately, you’d need a device like an absolute pressure gauge or a vacuum gauge. These instruments are specifically designed to measure pressure without relying on atmospheric conditions, giving you a true reading of the pressure in a given space.
I hope this helps clarify why barometers aren’t suitable for measuring absolute vacuum or absolute pressures! Feel free to ask if you have more questions .