VCE Physics/Unit 1/AoS 3 : What is matter and how is it formed?

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Description from the Study Design[edit]

In this area of study students explore the nature of matter, and consider the origins of atoms, time and space. They examine the currently accepted theory of what constitutes the nucleus, the forces within the nucleus and how energy is derived from the nucleus.

In This Area of Study[edit]

Template:VCE Physics/Unit 1/AOS 3 TOC

Comments about this Area of Study[edit]

The description of this Area of Study is a little "odd" for several reasons:

  • It shys away from using the term cosmology to describe the study of the origins and evolution of the universe, and the term nuclear physics to summarise the study of the nucleus. That's a bit like studying classical mechanics but not being told it's referred to as that.
  • Apparently we are considering the "origin of atoms...". Why pick on atoms? They're not a particularly fundamental subset of the particle zoo. What about quarks, leptons, the nucleus, molecules or some other subset like hadrons? It would make more sense if this sentence was changed to "the origins of matter, time and space".
  • "They examine the currently accepted theory of what constitutes the nucleus...". The text seems to imply that our current theories of the nucleus are ripe for change; that's news to me! Sure, we know we need to make some changes to theory if we're going to bring together the Standard Model and General Relativity, but any such changes are not going to significantly impact our understanding of the nucleus. Any changes will mainly impact our understanding of the universe at the planck scale (or similar) and might have something significant to say about our understanding of aspects of the universe such as black holes. How do we know this?... because we can currently calculate very accurately how the nucleus works (theoretical calculations closely match experimental values). There is very very little room for change. Our ability to make accurate calculations has tended to break down at the level of the substructure of the proton or neutron, but even then, the issue is our ability to do the math dictated by the theory, not any problem with the theory. So, for example, we are only recently getting good at answering questions such as "What makes up the proton's mass and how much do various aspects contribute?" There are readable articles about recent work on this, which make it clear our struggles have been with calculations in Quantum Chromodynamics (QCD, the relevant part of the standard model) not doubts about the validity of QCD itself – recent advances are due to recent advances in computing power, in combination with improved mathematical techniques.

This last dot point is a really important point about how science works. Yes, our understanding of the universe has evolved over time. However, it's not about throwing out the understanding we have previously gained, but building upon it. This is particularly true given how we've refined our understanding of the universe since around the time of Newton. For example, Einstein didn't "prove Newton wrong" he built on Newton's work and expanded the applicability of concepts such as energy and momentum to aspects of the universe that had not been experimentally accessible in Newton's time. At low speeds (small compared to the speed of light) Special Relaitivity approximates to Newtonian mechanics. Newton was not "wrong", his ideas were not just "currently accepted", they were shown to be correct because calculations based on the theory matched experiment, time and again... and they still do, to significant levels of precision. His ideas just needed to be extended in line with our expanded ability to investigate the universe. So, our understanding of the nucleus will not be impacted by any further changes to current theory, in a similar fashion to how the advent of Special Relativity did not impact how we used classical mechanics in the realm of, for example, building cars. Students will not just study "the currently accepted theory of what constitutes the nucleus", they will study what will forever be understood as constituting the nucleus, because this understanding has been confirmed by an almost uncountable number of experiments.