Many students hold a range of atom models, including hybrid models consisting of combinations of different models and incorrect ideas

Students’ atomic models include: (1) A planetary model, in which the electron orbits in a circle of constant radius, (2) a transitional model, in which the electron moves along a sinusoidal path, and (3) a probabilistic model, in which the position of the electron is uncertain. They often confuse and conflate two or more models.

Resources to Address This

• Use this teaching guidance to inform your approach to developing student’s ideas about atomic structure and nuclear decay. It compares an unstable and stable nucleus and their behaviour over time.

  The material can be used to introduce the concepts of nuclear stability and then half-life.

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• Rutherford’s experiment is one of the key points in the development of nuclear model and so has great significance. Use these materials to start a discussion about the experiment and its significance in the development of atomic theory, connecting the scattering effect to Coulomb’s Law.

  There is also a description about how to use a physical analogue of the experiment which the students can carry out to help them understand the forces involved and how the ‘alpha’ particles behave.

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• This resource develops students’ understanding of the scale of the size of the nucleus in comparison with the size of the atom. It helps to develop a mathematical relationship for the distance of closest approach of alpha particles using Coulomb’s Law and some example calculations. These are then used to discuss the sizes of atoms and nuclei.

  There is also a useful discussion about the upper limit of nucleus size and some of the issues with a nuclear model which lead to the development of quantum physics.

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• This set of videos discusses a range of approaches and models which can be used to develop and understanding of the models used for atoms and the nucleus.

  This includes some approaches for describing the changes which occur during nuclear decay and half-life along with some precursor work on states of matter.

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• This video outlines the Standard Model and can be used to discuss the changes which result in beta decay within the nucleus.

  The video can enhance students’ understanding of why beta decay can occur and why this leads to the production of particles which are not found within the nucleus (electrons and positrons).

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References

• Unver, A. O. and Arabacioglu, S., (2015) Helping pre-service science teachers to understand atomism through observations and experiments, Journal of Baltic Science Education, 14 (1)

  64-84.

• Prather, E., (2005) Student' Beliefs about the role of atoms in radioactive decay and half-life, Journal of Geoscience Education, 53 (4)

  345-354.

• Petri, J. and Niedderer, H., (1998) A learning pathway in high‐school level quantum atomic physics, International Journal of Science Education, 20 (9)

  1075-1088,

  https://doi.org/10.1080/0950069980200905.

  DOI: 10.1080/0950069980200905

• Müller, R. and Wiesner, H. (2002) Teaching quantum mechanics on an introductory level, American Journal of Physics, 70 (3)

  200-209.

  DOI: 10.1119/1.1435346

• Fischler, H. and Lichtfeldt, M. (1992) Modern Physics and Students' Conceptions, International Journal of Science Education, 14 (2)

  181-190.