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Pascals explained

The pascal (Pa) is the International System of Units (SI) derived unit of pressure and stress, defined as one newton per square meter. It quantifies internal pressure, stress, Young's modulus, and tensile strength, serving as a fundamental measurement in physics and engineering.

Symbol

The symbol for the pascal is Pa.

Applications of the Pascal

The pascal is utilized across various fields:

  • Meteorology: Atmospheric pressure is commonly measured in hectopascals.
  • Engineering: Material properties such as tensile strength and Young's modulus are expressed in pascals, with megapascal (MPa) being a standard unit.
  • Medicine: Blood pressure readings are traditionally in millimeters of mercury (mmHg), but can be converted to kilopascals (kPa) for SI consistency.
  • Acoustics: Sound pressure levels are measured in pascals, indicating the force of sound waves on surfaces.

Measuring Instruments

Instruments used to measure pressure in pascals include:

  • Barometers: Measure atmospheric pressure.
  • Manometers: Gauge pressure in fluids.
  • Pressure Sensors: Detect and transmit pressure readings in various systems.

Origin

The pascal is named after Blaise Pascal, a French mathematician, physicist, and inventor. Pascal's contributions to fluid mechanics and pressure studies were instrumental in understanding atmospheric pressure and vacuum. In recognition of his work, the unit of pressure was named the pascal during the 14th General Conference on Weights and Measures in 1971.

FAQs

Why is the pascal considered a small unit for measuring pressure?

One pascal equals one newton per square meter, which is a relatively small amount of pressure. Therefore, kilopascals (kPa) or megapascals (MPa) are often used in practical applications to represent larger pressures more conveniently.

How does the pascal relate to other units of pressure like psi?

One pascal is approximately 0.000145 pounds per square inch (psi). Conversely, one psi equals about 6,895 pascals. While the pascal is the SI unit, psi is commonly used in certain regions and industries, particularly in the United States.

What is the significance of the hectopascal in meteorology?

The hectopascal (hPa) is equivalent to the millibar (mb), a unit historically used in meteorology. Since 1 hPa equals 100 pascals, and atmospheric pressure at sea level is about 1013 hPa, this unit provides a convenient scale for reporting atmospheric pressure.

How do I convert pascals to other pressure units?

Use the links below for easy conversions from pascals to other pressure units available on this website.