298.15 K is 25 C, not 0 (0 is defined to be at 273.15)

Signed-off-by:  <manuel.freire@fdi.ucm.es>

AUTHORS

@@ -96,3 +96,4 @@ Gabe Mulley <gabe@edx.org>
 Iain Dunning <idunning@mit.edu>
 Olivier Marquez <oliviermarquez@gmail.com>
 Florian Dufour <neurolit@gmail.com>
+Manuel Freire <manuel.freire@fdi.ucm.es>

common/lib/calc/calc/calc.py

@@ -57,7 +57,7 @@ DEFAULT_VARIABLES = {
     'pi': numpy.pi,
     'k': scipy.constants.k,  # Boltzmann: 1.3806488e-23 (Joules/Kelvin)
     'c': scipy.constants.c,  # Light Speed: 2.998e8 (m/s)
-    'T': 298.15,  # 0 deg C = T Kelvin
+    'T': 298.15,  # Typical room temperature: 298.15 (Kelvin), same as 25C/77F
     'q': scipy.constants.e  # Fund. Charge: 1.602176565e-19 (Coulombs)
 }
 

common/lib/calc/calc/tests/test_calc.py

@@ -370,7 +370,7 @@ class EvaluatorTest(unittest.TestCase):
             ('pi', 3.1416, 1e-4),
             ('k', 1.3806488e-23, 1e-26),  # Boltzmann constant (Joules/Kelvin)
             ('c', 2.998e8, 1e5),  # Light Speed in (m/s)
-            ('T', 298.15, 0.01),  # 0 deg C = T Kelvin
+            ('T', 298.15, 0.01),  # Typical room temperature (Kelvin)
             ('q', 1.602176565e-19, 1e-22)  # Fund. Charge (Coulombs)
         ]
         for (variable, value, tolerance) in default_variables:

docs/course_authors/source/appendices/e.rst

@@ -580,7 +580,7 @@ default. These include:
 - ``pi``
 - ``k``: the Boltzmann constant (~1.38e-23 in Joules/Kelvin)
 - ``c``: the speed of light in m/s (2.998e8)
-- ``T``: the positive difference between 0K and 0°C (285.15)
+- ``T``: typical room temperature (298.15 Kelvin, same as 25C/77F)
 - ``q``: the fundamental charge (~1.602e-19 Coloumbs)
 
 Operators and Functions