Definition:Standard Atmosphere
Definition
The standard atmosphere is a unit of pressure.
It is defined as being:
It is usually used to measure the pressure of a gas.
Conversion Factors
| \(\ds \) | \(\) | \(\ds 1\) | standard atmosphere | |||||||||||
| \(\ds \) | \(=\) | \(\ds 101 \, 325\) | pascals (newtons per square metre) | |||||||||||
| \(\ds \) | \(=\) | \(\ds 1 \cdotp 01325 \times 10^6\) | bayre (dynes per square centimetre) | |||||||||||
| \(\ds \) | \(\approx\) | \(\ds 760\) | millimetres of mercury | |||||||||||
| \(\ds \) | \(\approx\) | \(\ds 76\) | centimetre of mercury | |||||||||||
| \(\ds \) | \(\approx\) | \(\ds 14.70\) | pounds per square inch | |||||||||||
| \(\ds \) | \(\approx\) | \(\ds 406 \cdotp 8\) | inches of water |
Symbol
The symbol used to denote the standard atmosphere is variously seen as follows:
The usual symbol used on $\mathsf{Pr} \infty \mathsf{fWiki}$ to denote the standard atmosphere is $\mathrm {atm}$.
A variant symbol used to denote the standard atmosphere is $\mathrm {Int \, atm}$.
This reflects its variant name of international atmosphere.
Also defined as
The standard atmosphere was originally defined as:
- The amount of pressure that will support a column of mercury $760$ millimetres high at $0 \cels$ at sea level at latitude $45 \degrees$.
However, after having been redefined to be exactly $101 \, 325$ pascals, the standard atmosphere is now approximately $759.99998 \, 92$ millimetres of mercury.
Also known as
The standard atmosphere is also seen in some older works as the international atmosphere.
Some sources refer to it merely as an atmosphere.
Also see
Sources
- 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $2.$ Unit Conversion Factors
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): atmosphere
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): pressure
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): atmosphere
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): pressure