Reflection
A recurring temptation is to confuse the physical law with the reality it describes.
But Newton’s law is not the world: it is one of our most fortunate representations of the world. If we push the model far enough — speeds close to that of light , atomic scales — we find that the model breaks down, and we must build a new one. Not because Newton was wrong, but because every model has a domain of validity.
Part of a physicist’s craft is recognising where a model holds. The rest of a physics course is a journey through ever wider models, each of which contains the previous one as a limiting case: special relativity contains Newtonian mechanics for , quantum mechanics contains it for objects large enough. This is not a sequence of corrected mistakes, but a sequence of increasingly detailed maps of the same territory (Feynman 1963; Arons 1997).
This awareness changes the way one does lab work: when the data deviate from a law, the right question is not just “is the law wrong?”, but also “am I stepping outside the domain in which this law holds?”.
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Topics: Metodo sperimentale
Related exercises: Esercizio svolto — Pallina rimbalzante (semilog) · Problema — Batteri e grafico semilog · Problema — Stima di Fermi, misure di g