# Year 12 – From the Universe to the Atom

###### Material moved from options to core syllabus

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)

Resource – Emission and Absorption Spectra – 4 pages

Resource – Hertzsprung Russell Diagram – 3 pages

Resource – Origins of the Elements – 4 pages

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)

Resource – Nuclear model of the atom – 4 pages

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

Resource – Origins of the Universe – 3 pages

Resource – Quantised energy levels – 3 pages

Resource – De Broglie – Schrodinger – 2 pages

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 $(E = mc^2)$

Resource – Radioactive Decay – 3 pages

Resource – Fission and Fusion – 3 pages

Resource – Nuclear Energy Calculations – 4 pages