AQA A Level Physics复习笔记2.5.6 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• Claims that are from research that is not peer-reviewed should always be questioned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