Using CGS or SI Units: When to Choose?

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Discussion Overview

The discussion revolves around the choice between CGS and SI units in physics, exploring when one might be preferred over the other. Participants examine the implications of using different unit systems and the potential trends in their usage.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant notes that consistency in unit usage is crucial, regardless of the system chosen, and expresses a personal preference for SI due to familiarity.
  • Another participant suggests that while SI is becoming more prevalent, the ability to switch between unit systems is important.
  • A claim is made that CGS is declining in use, with MKS (a variant of SI) gaining traction.
  • A later reply highlights that some fundamental constants, like the Fine-structure constant, are traditionally expressed in CGS units, indicating a continued relevance of CGS in certain contexts.

Areas of Agreement / Disagreement

Participants express differing views on the relevance and preference for CGS versus SI units, with no consensus reached on which system is definitively better or more appropriate.

Contextual Notes

The discussion reflects varying levels of familiarity with unit systems and does not resolve the implications of transitioning between them or the specific contexts in which one might be favored over the other.

Saketh
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I have a simple question.

I understand the quantitative differences between cgs and SI units, but when will I be expected to use one over the other? For example, do physicists prefer one set of units?

Thanks for the help.
 
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I really doesn't matter which system you use. The important thing is to be consistent with units. I was taught with the SI system, so I have come to prefer it, but that's not to say that it is better than cgs. Its a matter of preference and being able to move from one system to another. In fact its better that you be able to move between systems. But I guess the times will soon change and one can only speculate that the SI will out do cgs, as SI is widely used.
 
The short answer is that cgs is on the way out and mks is on the way in.
 
Crosson said:
The short answer is that cgs is on the way out and mks is on the way in.

except the real, hard-core physicists keep saying that the Fine-structure constant is:

[tex]\alpha = \frac{e^2}{\hbar c}[/tex]

which is the cgs way of saying it. the MKS (and general unit system) way to say it is:

[tex]\alpha = \frac{e^2}{\hbar c (4 \pi \epsilon_0)}[/tex]
 

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