Year 12 – From the Universe to the Atom – School of Physics HSC Physics Module

Origins of the Elements

Inquiry question: What evidence is there for the origins of the elements?

Students:

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 (ACSPH138)
analyse and apply Einstein’s description of the equivalence of energy and mass and relate this to the nuclear reactions that occur in stars (ACSPH031)
account for the production of emission and absorption spectra and compare these with a continuous black body spectrum (ACSPH137)
investigate the key features of stellar spectra and describe how these are used to classify stars
investigate the Hertzsprung-Russel 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)

Structure of the Atom

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

Students:

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
- Milikan’s oil drop experiment (ACSPH026)
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 (ACSPH026)

Quantum Mechanical Nature of the Atom

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

Students:

assess the limitations of the Rutherford and Bohr atomic models
investigate the line emission spectra to examine the Balmer series in hydrogen (ACSPH138)
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:
- $E = hf$
- $E = \frac{hc}{\lambda}$
- $\frac{1}{\lambda} = R \Big[\frac{1}{n^2_f} - \frac{1}{n^2_i}\Big]$ (ACSPH136)
investigate de Broglie’s matter waves, and the experimental evidence that developed the following formula:
- $\lambda = \frac{h}{mv}$ (ACSPH140)
analyse the contribution of Schrodinger to the current model of the atom

Properties of the Nucleus

Inquiry question: How can the energy of the atomic nucleus be harnessed?

Students:

analyse the spontaneous decay of unstable nuclei, and the properties of the alpha, beta and gamma radiation emitted (ACSPH028, ACSPH030)
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:
- $N_{t} = N_{o}e^{-\lambda t}$
- $\lambda = \frac{ln(2)}{t_{\frac{1}{2}}}$
where $N_t =$ number of particles at time $t, N_o =$ number of particles present at $t = 0, \lambda =$ decay constant, $t_{\frac{1}{2}} =$ time for half the radioactive amount to decay ACSPH029)
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 (ACSPH033, ACSPH034)
analyse relationships that represent conservation of mass-energy in spontaneous and artificial nuclear transmissions, including alpha decay, beta decay, nuclear fission, and nuclear fusion (ACSPH032)
account for the release of energy in the process of nuclear fusion (ACSPH035, ACSPH036)
predict quantitatively the energy released in nuclear decays or transmutations, including nuclear fission and nuclear fusion, by applying: (ACSPH031, ACSPH035, ACSPH036)
- the law of conservation of energy
- binding energy
- Einstein’s mass-energy equivalence relationship $(E = mc^2)$