Question

Why is it important to use official values of physical constants with high degrees of certainty associated with them, rather than using textbook values?

Answer 1

Ans. With development of technologies, the values of several constants are gradually updated to next decimal places and so on.

The textbooks often present a value that is easy to do calculations. For example, most often we use speed of light to be 33.0 x 10⁸ m/s for calculation purpose. Many times the value serve our purpose. But the times when we seek greater accuracy and certainty, like determination of photon’s wavelength or energy or quantum physics calculations, a more certain value, speed of light = 299792458 m/s must be used.

# The text book values are good for solving textbook question.

However when it comes to design an experiment, say preparing a buffer for animal cell culture, all the values of chemicals used must be with maximum certainty possible – say pKa value of weak acids must be as certain as possible.

Similarly, when designing and evaluating bioreactors, aerodynamics, hydrodynamics, molecular interactions at atomic scale and many others where values with highest certainty is always desirable, all the values must be used to their maximum certainty. It is use of these values that have lead the science develop; and vice-versa.

# Adoption of official values with higher certainty, published by CRC, IUPAC or other respective authorities, also correlates the experimental outputs at different part of the globe simultaneously with aiding better reproducibility of the experiment. Reproducibility is one of the main feature of science that facilitates anyone to modify and carry forward an experiment/ study from its original author. This feature makes it possible to gradually modify a system, say chemical modification of antibiotics and millions more, and makes the science generate a better, more controllable system.