What Is Pascal?
The pascal, written as Pa, is a unit used to measure pressure. Pressure tells us how much force is pushing on a certain area. For example, air in a balloon or water in a pipe has pressure. One pascal is a very small amount of pressure, so in real life we often use bigger units made from pascals, like kilopascals.
Definition
The pascal is the official metric unit for pressure in the International System of Units, also called SI.
By definition:
1 pascal (1 Pa) is the pressure made when a force of 1 newton pushes on an area of 1 square meter.
In simple words, if you spread a small push, called one newton, over a square as big as one meter by one meter, the pressure on that square is one pascal.
Because 1 Pa is very small, we often use:
- kilopascal (kPa) which is 1 000 Pa
- megapascal (MPa) which is 1 000 000 Pa
History / Origin
The pascal is named after Blaise Pascal, a French scientist and mathematician who lived in the 1600s. He studied air pressure and vacuum and helped people understand how pressure works in fluids and gases.
For a long time, people used older units to measure pressure, like atmospheres and bars. In the 1900s, scientists wanted one clear and standard system of units for all science and engineering. This system is called the International System of Units, or SI.
In 1971, an international meeting of scientists and measurement experts officially chose the name pascal for the SI unit of pressure. Since then, the pascal has been used in science, engineering, and many technical fields all over the world.
Symbol & Abbreviation
The pascal has a short symbol and some related forms.
- Full name Pascal
- Unit symbol Pa
- Base form 1 Pa
- Common larger forms
- 1 kPa kilopascal equals 1 000 Pa
- 1 MPa megapascal equals 1 000 000 Pa
The P is capital because the unit is named after a person, Blaise Pascal. The a is small. There is no dot after Pa.
Current Use Around the World
The pascal is used worldwide in science, engineering, weather reports, and many machines. Here are some common uses.
- Weather and atmosphere
- Meteorologists use pascals to measure air pressure.
- Weather maps often show pressure in hectopascals hPa, which is equal to millibars.
- Engineering and building
- Engineers use kPa and MPa to measure pressure in pipes, tanks, and machines.
- MPa is often used for material strength, like how strong concrete or steel is.
- Industrial and lab work
- Laboratories use pascals to measure gas pressure in experiments.
- Vacuum systems use Pa to show how empty the space is. Very low pressure means a strong vacuum.
- Everyday life
- Car tire pressure is often given in kilopascals kPa or in psi in some countries.
- Some home appliances, like pressure washers and air compressors, show pressure in kPa, MPa, or bar, which can be converted to Pa.
Example Conversions
Here are some useful conversions between pascals and other common pressure units.
| Pressure | In Pascals Pa |
|---|---|
| 1 Pa | 1 Pa |
| 1 kPa kilopascal | 1 000 Pa |
| 1 MPa megapascal | 1 000 000 Pa |
| 1 bar | 100 000 Pa |
| 1 atmosphere atm | about 101 325 Pa |
| 1 psi pound per square inch | about 6 895 Pa |
| Standard air pressure at sea level | about 101 325 Pa also written as 101.325 kPa |
Some quick examples in words:
- If a tire pressure is 200 kPa, that is 200 000 Pa.
- If a pressure gauge reads 2 MPa, that is 2 000 000 Pa.
- 1 bar is a little less than the air pressure at sea level, which is about 1.013 bar.
Related Units
Many other pressure units are related to the pascal. Here are some of the most common ones.
- Kilopascal kPa 1 kPa equals 1 000 Pa. Often used in weather reports and tire pressure.
- Megapascal MPa 1 MPa equals 1 000 000 Pa. Often used in engineering and material strength.
- Gigapascal GPa 1 GPa equals 1 000 000 000 Pa. Used for very high pressures, like in geology and material science.
- Bar 1 bar equals 100 000 Pa. Used in weather, diving, and industry.
- Atmosphere atm 1 atm is about 101 325 Pa. This is close to average air pressure at sea level.
- Millimeter of mercury mmHg or torr Used in medicine and vacuum systems. 1 mmHg is about 133.3 Pa.
- psi pound per square inch Used in some countries for tires and tools. 1 psi is about 6 895 Pa.
FAQs
Q: What does 1 pascal feel like?
A: One pascal is a very tiny pressure. It is much smaller than what we feel from normal air. You would not notice a change of just 1 Pa on your skin.
Q: Why do scientists prefer pascals instead of psi or bar?
A: Scientists like pascals because they fit the SI system, which connects cleanly with other units like newtons and meters. This makes formulas and calculations easier and more exact.
Q: Why do weather reports often use hPa instead of Pa?
A: Air pressure at Earths surface is around 100 000 Pa, which is a big number. Using hectopascals hPa cuts two zeros, so 101 325 Pa becomes 1013.25 hPa, which is easier to read and compare.
Q: How is pascal different from bar or atmosphere?
A: The pascal is the basic SI unit. Bar and atmosphere are older units. They are both equal to large numbers of pascals. For example, 1 bar equals 100 000 Pa and 1 atm equals about 101 325 Pa.
Q: Where do I see pascals in daily life?
A: You may see kPa on car tire labels, air pumps, or pressure washers. Weather apps may use hPa. Even if the tool shows bar or psi, those values can be converted to pascals.
Q: Is pascal only used for gases like air?
A: No. Pascal can measure pressure in gases and in liquids or even in solids. For example, water pressure in pipes, oil pressure in engines, and stress in building materials can all be given in pascals.