Barometer

Definition

A barometer is an instrument that measures atmospheric pressure. It is commonly used in meteorology and fluid mechanics to determine altitude and forecast weather.

5 Must Know Facts For Your Next Test

1. Barometers can be of two main types: mercury barometers and aneroid barometers.
2. Mercury barometers use a column of mercury in a glass tube; the height of the mercury column indicates atmospheric pressure.
3. Aneroid barometers use a small, flexible metal box called an aneroid cell, which expands and contracts with changes in pressure.
4. The standard atmospheric pressure at sea level is approximately 1013.25 millibars (mb) or 760 millimeters of mercury (mmHg).
5. Barometric readings are crucial for understanding fluid dynamics and predicting weather patterns.

Review Questions

• What are the two main types of barometers?
• How does a mercury barometer measure atmospheric pressure?
• What is the standard atmospheric pressure at sea level in both millibars and millimeters of mercury?

Related terms

Atmospheric Pressure: The force per unit area exerted by the weight of the atmosphere above a surface.

Fluid Dynamics: The study of fluids (liquids and gases) in motion.

Hydrostatic Pressure: $P = \rho gh$, where $P$ is the hydrostatic pressure, $\rho$ is the fluid density, $g$ is acceleration due to gravity, and $h$ is the height of the fluid column.