Teacher’s notes
Models of the atom from Democritus to Rutherford
Integrated strands
Science concept
The atom is composed of many different kinds of sub-atomic particles which are arranged in particular ways.
Nature of Science Theme
- All science knowledge is, in principle, subject to change…
- Scientists’ understandings change as new evidence becomes available.
DSSA Investigation Focus
- Students typically investigate existing science knowledge…
- Role-playing is one way that students can investigate existing science knowledge.
Rationale
Scientific knowledge about the atom has evolved as new evidence has been discovered. The discovery of sub-atomic particles changed how scientists view the atom. This is an area where students can gain an understanding of how science ideas change over time.
Activity
Curriculum level 5-8 Material world Topic
Atoms, ions, and molecules
Type of investigation
Modelling
What you need
- From Democritus to Rutherford: Developing our understanding of atomic structure (a play).
Note: Supporting activity resources are provided below.
Focus
- How would early scientists have shown that matter was made of units too small to be seen?
- Why do you think scientists’ views of atomic structure have changed over time?
- How do scientists develop ideas about structures that are too small to see with the naked eye?
- Have scientists’ ideas about atoms changed over time only because their instrumentation has become more powerful?
- What might drive scientists to keep looking for new explanations?
Exploration
- Get students to read and/or act out the play.
Extension
- Research the contribution made by one or some of the scientists mentioned at the end of the play: Anderson, Aston, Avogadro, Berzelius, Bohr, Cannizzaro, Curie, de Broglie, Fermi, Gay-Lussac, Hahn, Heisenberg, Heitler, Irene Joliot-Curie, Landolt, London, Newton, Marley, Meitner, Mendeleef, Mosely, Pauli, Planck, Priestley, Proust, Schrödinger.
Reflection
- Why do we need more than one type of model for complex phenomena? (No one model can represent all the features of a reality. Where something is complex, scientists pick the model that is most relevant to the aspect under investigation.)
- How do scientists use other ideas to develop better understanding? (For example, they build on other ideas either directly or by challenging them.)
- Do scientists have a complete understanding of the structure of atoms and how they act?
- How do models help scientists understand the complexities of subatomic particles?
- If you were going to extend this play to the modern day, whose ideas would you include, and why? (For more on atomic models see Selecting models of an atom.)