The key thing in a good system of units is to define units in a way that depends only on physical properties of nature.
Ideally (or basically necessarily?) the starting point generally has to be discrete phenomena, e.g.
- number of times some light oscillates per second
- number of steps in a quantum Hall effect or Josephson junction
What we don't want is to have macroscopic measurement artifacts, (or even worse, the size of body parts! Inset dick joke) as you can always make a bar slightly more or less wide. And even metals evaporate over time! Though the mad people of the Avogadro project still attempted otherwise well into the 2010s!
Standards of measure that don't depend on artifacts are known as intrinsic standards.
Computational physics is a good way to get valuable intuition about the key equations of physics, and train your numerical analysis skills:
- classical mechanics
- "Real-time heat equation OpenGL visualization with interactive mouse cursor using relaxation method" under the best articles by Ciro Santillis
- phet.colorado.edu PhET simulations from University of Colorado Boulder
Other child sections:
A polynomial of degree 1, i.e. of form .
The piano is the most elegant non-electronic instrument. But it requires way too many strings, so expensive and not portable.
The guitar is kind of the opposite.
After computer sound synthesis however, all of these distinctions become meaningless.
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