If you’re working with physics equations or scientific simulations in Python, you don\u2019t need to manually define constants like the speed of light or Avogadro\u2019s number. The scipy.constants module gives you immediate access to hundreds of predefined physical and mathematical constants\u2014all with correct units and precision. You\u2019ll also find unit conversion factors, allowing you to convert between metric, imperial, and other systems cleanly in code.<\/p>\n\n\n\n
SciPy Beginner’s Learning Path<\/strong><\/p>\n\n\n\n Start by importing the module:<\/p>\n\n\n Now you can directly use constants like:<\/strong><\/p>\n\n\n Some of the most used constants:<\/strong><\/p>\n\n\n You can also access groups of constants:<\/p>\n\n\n This gives you a dictionary. Each entry includes the value, unit, and uncertainty:<\/p>\n\n\n Other useful dictionaries:<\/p>\n\n\n\n The scipy.constants module supports many unit conversions via named variables:<\/p>\n\n\n Also available:<\/p>\n\n\n\n Use Planck\u2019s relation: E = h\u03bd<\/strong><\/p>\n\n\n To convert to electron volts:<\/strong><\/p>\n\n\n Instead of defining your own \u03c0, just use:<\/strong><\/p>\n\n\n Instead of 9.8 for gravity (which is approximate), use:<\/strong><\/p>\n\n\n This helps ensure that your code is scientifically consistent and precise.<\/strong><\/p>\n\n\n\n Using scipy.constants isn’t just convenient\u2014it\u2019s essential for scientific integrity. It removes guesswork, ensures unit consistency, and makes your code easier to read and verify. Anytime you’re working with a known constant or unit conversion, check if SciPy already has it.<\/p>\n\n\n\n For more examples, continue with scipy.constants.find(), which lets you search constants by keyword.<\/p>\n","protected":false},"excerpt":{"rendered":" If you’re working with physics equations or scientific simulations in Python, you don\u2019t need to manually define constants like the speed of light or Avogadro\u2019s number. The scipy.constants module gives you immediate access to hundreds of predefined physical and mathematical constants\u2014all with correct units and precision. You\u2019ll also find unit conversion factors, allowing you to […]<\/p>\n","protected":false},"author":6,"featured_media":64472,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[737],"tags":[],"class_list":["post-64461","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scipy"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts\/64461","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/comments?post=64461"}],"version-history":[{"count":0,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts\/64461\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/media\/64472"}],"wp:attachment":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/media?parent=64461"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/categories?post=64461"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/tags?post=64461"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\n
Why Use scipy.constants?<\/h2>\n\n\n\n
\n
\n\n\n\nHow to Acess SciPy Constants?<\/h2>\n\n\n\n
\nfrom scipy import constants\n<\/pre><\/div>\n\n\n
\nenergy = 2 * constants.c ** 2 # E = 2 * c\u00b2\nprint("Energy:", energy, "m\u00b2\/s\u00b2")\n\n<\/pre><\/div>\n\n\n\nconstants.c # speed of light in vacuum [m\/s]\nconstants.h # Planck\u2019s constant [J\u22c5s]\nconstants.k # Boltzmann constant [J\/K]\nconstants.G # gravitational constant [m\u00b3\/kg\/s\u00b2]\nconstants.R # gas constant [J\/mol\/K]\nconstants.N_A # Avogadro\u2019s number [1\/mol]\nconstants.e # elementary charge [C]\n\n<\/pre><\/div>\n\n\n
\n\n\n\nHandy SciPy Submodules for Categories<\/h2>\n\n\n\n
\nfrom scipy.constants import physical_constants\n<\/pre><\/div>\n\n\n
\nvalue, unit, uncertainty = physical_constants['Planck constant']\nprint(f"Planck constant: {value} {unit} \u00b1 {uncertainty}")\n<\/pre><\/div>\n\n\n\n
\n\n\n\nConverting Units<\/h2>\n\n\n\n
\n# Convert 10 calories to joules\ncal_to_joule = 10 * constants.calorie\nprint("10 cal =", cal_to_joule, "J")\n\n# Convert 1 inch to meters\nprint("1 inch =", constants.inch, "meters")\n\n<\/pre><\/div>\n\n\n\n
\n\n\n\nUsing SciPy Constants to Compute Photon Energy<\/h2>\n\n\n\n
\nfrequency = 5e14 # in Hz (visible light)\nenergy = constants.h * frequency\nprint("Photon energy:", energy, "J")\n<\/pre><\/div>\n\n\n\neV = energy \/ constants.e\nprint("Photon energy:", eV, "eV")\n<\/pre><\/div>\n\n\n
\n\n\n\nDon\u2019t Recalculate What SciPy Already Has<\/h2>\n\n\n\n
\nprint(constants.pi)\n\n<\/pre><\/div>\n\n\n
\nprint(constants.g) # Standard gravity in m\/s\u00b2\n\n<\/pre><\/div>\n\n\n
\n\n\n\nSummary<\/h2>\n\n\n\n