From the Universe to the Atom

This lesson comprises eight (8) master classes focusing on:

• Electrons, Protons, Neutrons
• Bohr's atomic model
• Quantum model of the atom
• Nuclear decay
• Energy in nuclear reactions
• The Standard Model
• The Big Bang Theory
• Astrophysics

Content:

PH12-15

What evidence is there for the origins of the elements?

• Investigate the processes that led to the transformation of radiation into matter that followed the ‘Big Bang’ 
• Investigate the evidence that led to the discovery of the expansion of the Universe by Hubble
• Analyse and apply Einstein’s description of the equivalence of energy and mass and relate this to the nuclear reactions that occur in stars
• Account for the production of emission and absorption spectra and compare these with a continuous black body spectrum
• Investigate the key features of stellar spectra and describe how these are used to classify stars
• Investigate the Hertzsprung-Russell diagram and how it can be used to determine the following about a star:
  • characteristics and evolutionary stage
  • surface temperature
  • colour
  • luminosity
• Investigate the types of nucleosynthesis reactions involved in Main Sequence and Post-Main Sequence stars, including but not limited to:
  • proton–proton chain
  • CNO (carbon-nitrogen-oxygen) cycle

How is it known that atoms are made up of protons, neutrons and electrons?

• Investigate, assess and model the experimental evidence supporting the existence and properties of the electron, including:
  • early experiments examining the nature of cathode rays
  • Thomson’s charge-to-mass experiment
  • Millikan's oil drop experiment
• Investigate, assess and model the experimental evidence supporting the nuclear model of the atom, including:
  • the Geiger-Marsden experiment
  • Rutherford’s atomic model
  • Chadwick’s discovery of the neutron

How is it known that classical physics cannot explain the properties of the atom?

• Assess the limitations of the Rutherford and Bohr atomic models
• Investigate the line emission spectra to examine the Balmer series in hydrogen
• Relate qualitatively and quantitatively the quantised energy levels of the hydrogen atom and the law of conservation of energy to the line emission spectrum of hydrogen using:
  • \( E=hf \)
  • \( E=\frac{hc}{\lambda} \)
  • \( \frac{1}{\lambda}=R[\frac{1}{n^2_f}-\frac{1}{n^2_i}] \)
• Investigate de Broglie’s matter waves, and the experimental evidence that developed the following formula:
  • \( \lambda=\frac{h}{mv} \)
• Analyse the contribution of Schrödinger to the current model of the atom

How can the energy of the atomic nucleus be harnessed?

• Analyse the spontaneous decay of unstable nuclei, and the properties of the alpha, beta and gamma radiation emitted
• Examine the model of half-life in radioactive decay and make quantitative predictions about the activity or amount of a radioactive sample using the following relationships:
  • \(N_t=N_0e^{-\lambda t} \)
  • \( \lambda=\frac{\ln 2}{t_{\frac{1}{2}}} \) where \( N_t \) = number of particles at time \( t \), \( N_0 \) = number of particles present at \( t=0 \), \( \lambda \) = decay constant, \( t_{\frac{1}{2}} \) = time for half the radioactive amount to decay
• Model and explain the process of nuclear fission, including the concepts of controlled and uncontrolled chain reactions, and account for the release of energy in the process
• Analyse relationships that represent conservation of mass-energy in spontaneous and artificial nuclear transmutations, including alpha decay, beta decay, nuclear fission and nuclear fusion
• Account for the release of energy in the process of nuclear fusion
• Predict quantitatively the energy released in nuclear decays or transmutations, including nuclear fission and nuclear fusion, by applying:
  • the law of conservation of energy
  • mass defect
  • binding energy
  • Einstein’s mass–energy equivalence relationship \( E=mc^2 \)

How is it known that human understanding of matter is still incomplete?

• Analyse the evidence that suggests:
  • that protons and neutrons are not fundamental particles
  • the existence of subatomic particles other than protons, neutrons and electrons
• Investigate the Standard Model of matter, including:
  • quarks, and the quark composition hadrons
  • leptons
  • fundamental forces
• Investigate the operation and role of particle accelerators in obtaining evidence that tests and/or validates aspects of theories, including the Standard Model of matter

PH12-5

• Derive trends, patterns and relationships in data and information
• Assess error, uncertainty and limitations in data
• Assess the relevance, accuracy, validity and reliability of primary and secondary data and suggest improvements to investigations

PH12-6

• Use modelling (including mathematical examples) to explain phenomena, make predictions and solve problems using evidence from primary and secondary sources
• Use scientific evidence and critical thinking skills to solve problems

PH12-7

• Select and use suitable forms of digital, visual, written and/or oral forms of communication
• Select and apply appropriate scientific notations, nomenclature and scientific language to communicate in a variety of contexts
• Construct evidence-based arguments and engage in peer feedback to evaluate an argument or conclusion