AQA A Level Physics

Revision Notes

2.5.6 Analysis of the Nature of Matter

Analysis of the Nature of Matter

The Evolving Field of Quantum Mechanics

  • The field of quantum mechanics is a relatively new field of research, compared to fields in classical mechanics (Newton’s laws, wave theory etc)
  • Around 1900, discoveries, such as the electron and the gamma photon, began to conflict with the existing models scientists held about the nature of matter
  • Soon after, new theories about the nature of matter began to emerge from Max Planck, Niels Bohr and Albert Einstein, who are seen as the pioneers of Quantum Theory
  • Unsurprisingly, the understanding of quantum mechanics and the nature of matter has changed over time
    • Scientists use the existing models to make predictions eg. wave theory
    • Sometimes the results of their experiments were not as predicted and did not fit with the existing model eg. the photoelectric effect
    • Scientists then have to change the model so that it can explain the new evidence eg. wave–particle duality

Development of Scientific Theories

  • When a new theory is suggested, such as de Broglie’s idea of particles acting as waves, the theory needs to be evaluated
  • Other scientists evaluate the theory in a process called peer review
  • When enough evidence is found to support the theory, it is validated
  • De Broglie’s theory is currently accepted to be correct until any conflicting evidence is found

Peer Review

  • Scientists across the world form a scientific community
  • Scientific claims from new research that is published in journals must be peer-reviewed or evaluated by other scientists who are experts in that field of science
  • During the peer review process, scientists must check:
    • Validity – does the research achieve what it says it does? Is the method appropriate and how have any errors been addressed?
    • Originality – are the results new or has anyone else already carried out similar research? If so, has their work been credited?
    • Significance – are the findings of the research important or ground-breaking?

Evaluating Scientific Claims

  • Claims that are from research that is not peer-reviewed should always be questioned
  • There could be a multitude of problems. These could be the method used, the accuracy of results or the conclusions drawn
  • Research should also be checked if it is:
    • Repeatable by the same scientists who carried it out
    • Reproducible by other teams of scientists

Timeline of the great advancements in quantum theory since 1900

Author: Katie

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.

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