Manometer

Definition

A manometer is an instrument used to measure the pressure of gases. It typically consists of a U-shaped tube filled with a liquid, such as mercury or water, where the difference in liquid levels indicates the pressure.

5 Must Know Facts For Your Next Test

1. Manometers measure gas pressure relative to atmospheric pressure or another reference point.
2. The basic principle involves balancing the gas pressure against a column of liquid within the U-tube.
3. A common type is the U-tube manometer, which can be open or closed at one end.
4. Differential manometers are used to measure the difference between two pressures.
5. Mercury is often preferred over water in manometers due to its higher density, which allows for more precise measurements.

Review Questions

• What is the primary function of a manometer?
• How does a U-tube manometer indicate gas pressure?
• Why might mercury be used instead of water in a manometer?

Related terms

Barometer: An instrument that measures atmospheric pressure, usually using mercury or aneroid cells.

Pressure:

The force exerted per unit area on the surface of an object, commonly measured in Pascals (Pa).

Gauge Pressure: $P_{gauge} = P_{absolute} - P_{atmospheric}$; it measures pressure relative to atmospheric pressure.