SciPy - Constants

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What are Scipy Constants?

The scipy.constants is a module within the SciPy library that provides a comprehensive set of physical constants and unit conversions. These constants are essential for scientific computations across various fields such as physics, astronomy, chemistry and engineering.

The module standardizes the values of fundamental physical quantities by making it easier for scientists and engineers to perform accurate and consistent calculations.

Before getting into detail of sciPy constants, let us compare the pi value by considering the following example −

import scipy.constants as constants
import math

# Print values of pi from SciPy and math modules
print("SciPy - pi = %.16f" % constants.pi)
print("Math - pi = %.16f" % math.pi)

When we execute the above code both the packages gives the output as below −

SciPy - pi = 3.1415926535897931
Math - pi = 3.1415926535897931

Types of Scipy Constants

In the scipy.constants module the constants are categorized into several types in which each serving different purposes across scientific disciplines. Heres a detailed overview of the types of constants available −

Physical Constants

In SciPy Physical Constants are predefined values for fundamental physical quantities that are used across various scientific and engineering disciplines. These constants are included in the scipy.constants module and are critical for calculations and simulations in physics, chemistry and engineering.

Following are the key physical constants available in the module scipy.constants −

Constant	Description	Value
c	Speed of light in vacuum	299,792,458 m/s
speed_of_light	Speed of light in vacuum	299,792,458 m/s
h	Planck constant	6.62607015 1034 Js
Planck	Planck constant	6.62607015 1034 Js
G	Newtons gravitational constant	6.67430 1011 mkg1s2
e	Elementary charge	1.602176634 1019 C
R	Molar gas constant	8.314 J/(molK)
Avogadro	Avogadro constant	6.02214076 1023 mol1
k	Boltzmann constant	1.380649 1023 J/K
electron_mass (or m_e)	Electron mass	9.10938356 1031 kg
proton_mass (or m_p)	Proton mass	1.672621923 1027 kg
neutron_mass (or m_n)	Neutron mass	1.675 1027 kg

Astronomical Constants

Astronomical constants are fundamental values used in astronomy and astrophysics to describe and quantify various properties of celestial objects and their interactions. These constants are essential for calculations involving orbital dynamics, celestial mechanics and the general behavior of astronomical systems.

Following are the few Astronomical constants available in scipy.constants module −

Constant	Description	Value
AU	Astronomical Unit	149,597,870.7 km
Light-year	Distance light travels in a year	9.4607 1012 km
Parsec	Distance at which one astronomical unit subtends an angle of one arc second	3.0857 1013 km
Solar Mass	Mass of the Sun	1.989 1030 kg
Solar Radius	Radius of the Sun	6.963 108 km
Jupiter Mass	Mass of Jupiter	1.898 1027 kg
Jupiter Radius	Radius of Jupiter	6.9911 107 m
Earth Mass	Mass of Earth	5.972 1024 kg
Earth Radius	Radius of Earth	6,371 km
Mean Distance Earth-Moon	Average distance from Earth to Moon	384,400 km
Mean Distance Earth-Sun	Average distance from Earth to Sun (AU)	149,597,870.7 km

Mathematical Constants

Mathematical constants are specific well-defined numbers that arise in various mathematical contexts. These constants are fundamental to many areas of mathematics, science and engineering.

Below is a list of some important mathematical constants, their definitions and their significance:

Constant	Description	Value	Description
Pi		3.141592653589793	Ratio of the circumference of a circle to its diameter. Appears in geometry, trigonometry, and calculus.
Euler's Number	e	2.718281828459045	Base of the natural logarithm. Important in calculus, growth models, and complex analysis.
Golden Ratio	or	1.618033988749895	Solution to = + 1. Appears in art, architecture, and nature.
Square Root of 2	2	1.414213562373095	Length of the diagonal of a unit square. Appears in geometry and trigonometry.
Square Root of 3	3	1.732050807568877	Length of the diagonal of a unit cube. Used in geometry and trigonometry.
Natural Logarithm of 2	ln(2)	0.693147180559945	Logarithm base e of 2. Important in information theory and exponential growth/decay models.
Catalan's Constant	G	0.915965594177219	Appears in combinatorial mathematics, specifically in problems related to lattice paths.
Apry's Constant	(3)	1.202056903159594	Value of the Riemann zeta function at 3. Important in number theory and mathematical analysis.
The Square of e	e	7.389056098930649	Exponential function of e. Useful in various exponential growth models.
The Logarithm of 10	log(10)	1.0	Base 10 logarithm of 10. Often used in scientific notation and logarithmic scales.
The Logarithm of 2	log(2)	0.301029995663981	Base 10 logarithm of 2. Used in information theory and computer science.
Euler-Mascheroni Constant		0.577215664901532	Appears in number theory and the study of harmonic series.
Feigenbaum Constant		4.669201609102990	Appears in the study of chaotic systems and bifurcations.
Khinchin's Constant	K	2.685452001065306	Appears in the study of continued fractions.
Glaisher-Kinkelin Constant	A	1.282427129100622	Appears in combinatorial mathematics and number theory.
Madhava-Leibniz Constant	M	0.946083070367183	Appears in the series expansion of .

Unit Conversion Constants

Unit conversion constants are values used to convert measurements from one unit to another. These constants are crucial in scientific, engineering and everyday calculations to ensure consistent and accurate conversions between different units of measurement. Below is a list of common unit conversion constants and their descriptions.

Conversion	From Unit	To Unit	Constant Value	Description
Length	Meter	Kilometer	0.001	1 meter is 0.001 kilometers.
Length	Meter	Centimeter	100	1 meter is 100 centimeters.
Length	Meter	Millimeter	1000	1 meter is 1000 millimeters.
Length	Inch	Centimeter	2.54	1 inch is 2.54 centimeters.
Length	Foot	Meter	0.3048	1 foot is 0.3048 meters.
Length	Yard	Meter	0.9144	1 yard is 0.9144 meters.
Area	Square Meter	Square Kilometer	1e-6	1 square meter is 1e-6 square kilometers.
Area	Square Meter	Square Centimeter	1e4	1 square meter is 10,000 square centimeters.
Volume	Liter	Cubic Meter	0.001	1 liter is 0.001 cubic meters.
Volume	Gallon (US)	Liter	3.78541	1 US gallon is approximately 3.78541 liters.
Volume	Milliliter	Cubic Centimeter	1	1 milliliter is 1 cubic centimeter.
Mass	Gram	Kilogram	0.001	1 gram is 0.001 kilograms.
Mass	Pound	Kilogram	0.453592	1 pound is approximately 0.453592 kilograms.
Mass	Ounce	Gram	28.3495	1 ounce is approximately 28.3495 grams.
Temperature	Celsius	Fahrenheit	F = (C 9/5) + 32	Formula to convert Celsius to Fahrenheit.
Temperature	Fahrenheit	Celsius	C = (F - 32) 5/9	Formula to convert Fahrenheit to Celsius.
Temperature	Kelvin	Celsius	C = K - 273.15	0 Kelvin is -273.15C.
Temperature	Celsius	Kelvin	K = C + 273.15	0C is 273.15 Kelvin.
Energy	Joule	Calorie	0.239006	1 joule is approximately 0.239006 calories.
Energy	Calorie	Joule	4.184	1 calorie is 4.184 joules.
Energy	Electronvolt	Joule	1.60218e-19	1 electronvolt is 1.60218e-19 joules.
Pressure	Pascal	Bar	1e-5	1 Pascal is 1e-5 bars.
Pressure	Atmosphere	Pascal	101325	1 atmosphere is 101,325 Pascals.
Speed	Kilometer per Hour	Meter per Second	0.277778	1 km/h is approximately 0.277778 m/s.
Speed	Mile per Hour	Meter per Second	0.44704	1 mph is approximately 0.44704 m/s.

List of Constants in SciPy

Here we have listed few constants available in scipy, but if we want to get all the constants available in scipy.constansts module below code can be executed −

import scipy
from scipy import constants
print(dir(scipy.constants))

Following are the all available constant methods in scipy.constants module −

['Avogadro', 'Boltzmann', 'Btu', 'Btu_IT', 'Btu_th', 'ConstantWarning', 'G', 'Julian_year', 'N_A', 'Planck', 'R', 'Rydberg', 'Stefan_Boltzmann', 'Wien', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '_codata', '_constants', '_obsolete_constants', 'acre', 'alpha', 'angstrom', 'arcmin', 'arcminute', 'arcsec', 'arcsecond', 'astronomical_unit', 'atm', 'atmosphere', 'atomic_mass', 'atto', 'au', 'bar', 'barrel', 'bbl', 'blob', 'c', 'calorie', 'calorie_IT', 'calorie_th', 'carat', 'centi', 'codata', 'constants', 'convert_temperature', 'day', 'deci', 'degree', 'degree_Fahrenheit', 'deka', 'dyn', 'dyne', 'e', 'eV', 'electron_mass', 'electron_volt', 'elementary_charge', 'epsilon_0', 'erg', 'exa', 'exbi', 'femto', 'fermi', 'find', 'fine_structure', 'fluid_ounce', 'fluid_ounce_US', 'fluid_ounce_imp', 'foot', 'g', 'gallon', 'gallon_US', 'gallon_imp', 'gas_constant', 'gibi', 'giga', 'golden', 'golden_ratio', 'grain', 'gram', 'gravitational_constant', 'h', 'hbar', 'hectare', 'hecto', 'horsepower', 'hour', 'hp', 'inch', 'k', 'kgf', 'kibi', 'kilo', 'kilogram_force', 'kmh', 'knot', 'lambda2nu', 'lb', 'lbf', 'light_year', 'liter', 'litre', 'long_ton', 'm_e', 'm_n', 'm_p', 'm_u', 'mach', 'mebi', 'mega', 'metric_ton', 'micro', 'micron', 'mil', 'mile', 'milli', 'minute', 'mmHg', 'mph', 'mu_0', 'nano', 'nautical_mile', 'neutron_mass', 'nu2lambda', 'ounce', 'oz', 'parsec', 'pebi', 'peta', 'physical_constants', 'pi', 'pico', 'point', 'pound', 'pound_force', 'precision', 'proton_mass', 'psi', 'pt', 'quecto', 'quetta', 'ronna', 'ronto', 'short_ton', 'sigma', 'slinch', 'slug', 'speed_of_light', 'speed_of_sound', 'stone', 'survey_foot', 'survey_mile', 'tebi', 'tera', 'test', 'ton_TNT', 'torr', 'troy_ounce', 'troy_pound', 'u', 'unit', 'value', 'week', 'yard', 'year', 'yobi', 'yocto', 'yotta', 'zebi', 'zepto', 'zero_Celsius', 'zetta']