SciPy Constants (original) (raw)
Last Updated : 5 Jul, 2025
In scientific and mathematical calculations, universal constants such as π (pi) or the gravitational constant G are frequently needed. Whether it's determining the area of a circle or calculating gravitational force, having reliable constants readily available helps streamline the process.
**Scipy.constants module in SciPy allows users to access collection of mathematical, physical and unit conversion constants effortlessly with a single line of code.
Accessing Constants
Constants can be accessed using the format:
scipy.constants.CONSTANT_NAME
Below listed constants are commonly used:
Python `
import scipy.constants as const
print("Pi:", const.pi) print("Golden ratio:", const.golden_ratio) print("Speed of light:", const.c) print("Gravitational constant:", const.G) print("Gas constant (R):", const.R) print("Boltzmann constant:", const.k) print("Proton mass:", const.proton_mass)
`
**Output
Accessing Constants Output
Finding Constants
Use the **find() method to search for constants by keyword.
Python `
import scipy res = scipy.constants.find("electron") print(res, end='\n')
`
**Output
Finding Constants Output
Physical Constants: Value, Unit and Uncertainty
Not only the value but also the corresponding unit and the degree of uncertainty of a physical constant can be retrieved using **physical_constants dictionary from **scipy.constants.
scipy.constants.physical_constants['name']
Python `
import scipy.constants as const
This return a tuple(vslue, unit, uncertainty)
print(const.physical_constants['alpha particle mass'])
`
**Output
(6.644657345e-27, 'kg', 2.1e-36)
**Example: Sample Use Cases
Python `
import scipy.constants as const
Area of a circle using pi
def area_of_circle(r): return const.pi * r * r
Gravitational force
def force_gravity(M, m, dist): return (const.G * M * m) / (dist ** 2)
print("Area of Circle:", area_of_circle(5)) print("Gravitational Force:", force_gravity(10, 5, 1))
`
**Output
Sample Use Case Output
Commonly Used Constants in SciPy
| Constants | Description |
|---|---|
| pi | Mathematical constant π |
| golden_ratio | Golden ratio |
| c or speed_of_light | Speed of light in vacuum |
| G | Gravitational constant |
| E | Elementary charge |
| R | Molar gas constant |
| alpha | Fine-structure constant |
| N_A | Avogadro constant |
| k | Boltzmann constant |
| sigma | Stefan-Boltzmann constant σ |
| m_e | Electron mass |
| m_p | Proton mass |
| m_n | Neutron Mass |
| h or Planck | Planck Constant |
Unit Conversion Constants
**Mass Units:
| Unit | Description |
|---|---|
| gram | One gram in kilograms. |
| grain | One grain in kilograms. |
| pound | One Pound in kilograms. |
| ounce | One Ounce in kilograms. |
| automic_mass | Atomics mass constant in kilograms. |
**Time Units:
| Unit | Description |
|---|---|
| minute | One minute in seconds. |
| hour | One hour in seconds. |
| day | One day in seconds. |
| year | One year in seconds. |
**Length Units:
| Units | Description |
|---|---|
| inch | One inch in meters. |
| foot | One foot in meters. |
| yard | One yard in meters. |
| pt | One point in meters. |
| micron | One Micron in meters. |
**Pressure Units:
| Units | Description |
|---|---|
| atm/atmosphere | The standard atmosphere in pascals. |
| bar | One bar in Pascals. |
| torr | One torr(mmHg) in pascals. |
**Area Units:
| Units | Description |
|---|---|
| hectare | One hectare in square meters. |
| acre | One acre in square meters. |
**Speed Units:
| Units | Description |
|---|---|
| kmh | Kilometer per hour in meter per second. |
| mph | Miles per hour in meter per second. |
| mach | One Match in meter per second. |
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