Barometer

Definition

A barometer is an instrument used to measure atmospheric pressure, which is the force exerted by the weight of the air above a given surface area. Barometers play a crucial role in understanding and predicting weather patterns, as changes in atmospheric pressure are closely linked to weather conditions.

5 Must Know Facts For Your Next Test

1. Barometers are used to measure both gauge pressure (the pressure above or below atmospheric pressure) and absolute pressure (the total pressure, including atmospheric pressure).
2. The variation of pressure with depth in a fluid, as described by the hydrostatic pressure equation, is the principle behind the operation of a barometer.
3. Barometers can be used to estimate the altitude or elevation of a location by measuring the decrease in atmospheric pressure with increasing height.
4. Aneroid barometers, which use a flexible metal capsule, are commonly used in modern weather stations and portable devices due to their compact size and durability.
5. Changes in atmospheric pressure, as measured by a barometer, are closely related to the formation and movement of weather systems, making barometers essential tools for weather forecasting.

Review Questions

• Explain how a barometer is used to measure pressure in the context of 11.3 Pressure.
  • A barometer is a device that measures atmospheric pressure, which is the force exerted by the weight of the air on a given surface area. The underlying principle behind a barometer's operation is the variation of pressure with depth in a fluid, as described in 11.4 Variation of Pressure with Depth in a Fluid. By measuring the change in pressure, a barometer can provide information about the current weather conditions and help predict future weather patterns, as discussed in 11.6 Gauge Pressure, Absolute Pressure, and Pressure Measurement.
• Describe how a barometer can be used to estimate the altitude or elevation of a location, as discussed in 11.4 Variation of Pressure with Depth in a Fluid.
  • The variation of pressure with depth in a fluid, as described by the hydrostatic pressure equation, is the principle behind the use of a barometer to estimate the altitude or elevation of a location. As you increase in elevation, the atmospheric pressure decreases due to the reduced weight of the air column above. By measuring this decrease in pressure using a barometer, you can calculate the approximate height or elevation of the location, as discussed in 11.4 Variation of Pressure with Depth in a Fluid.
• Analyze the role of a barometer in the context of 11.6 Gauge Pressure, Absolute Pressure, and Pressure Measurement, and explain how it can be used to differentiate between gauge pressure and absolute pressure.
  • In the context of 11.6 Gauge Pressure, Absolute Pressure, and Pressure Measurement, a barometer is a crucial instrument for measuring both gauge pressure and absolute pressure. Gauge pressure is the pressure above or below the surrounding atmospheric pressure, while absolute pressure is the total pressure, including atmospheric pressure. A barometer can be used to measure the absolute pressure of the atmosphere, which can then be used to calculate the gauge pressure by subtracting the known atmospheric pressure from the absolute pressure reading. This ability to differentiate between gauge and absolute pressure makes the barometer an essential tool for understanding and predicting weather patterns, as changes in atmospheric pressure are closely linked to the formation and movement of weather systems.

Related terms

Atmospheric Pressure: The pressure exerted by the weight of the earth's atmosphere on the surface below. It is measured in units of force per unit area, such as pascals (Pa) or millibars (mb).

Manometer: A type of barometer that measures pressure by using the height of a column of liquid, such as mercury or water, to indicate the pressure difference between two points.

Aneroid Barometer: A type of barometer that uses a sealed, flexible metal capsule to measure changes in atmospheric pressure, without the use of a liquid column.