Some students think that there is air between air molecules

More generally, some students think that between the molecules of a substance, the same substance exists. For instance, there is air between air molecules, water between water molecules, and rock between rock molecules.

References

• Andersson, B., (1990) Pupils' Conceptions of Matter and its Transformations (age 12-16), Studies in Science Education, 18, 53-85.

  This research shows that some of the misconceptions students have about matter are reinforced by the learning materials and approaches used in classrooms. Textbook illustrations can give false impressions about sizes, scales and movement and the limitations of models can give misleading ideas. This paper explains why teachers need to be aware of the misconceptions that can be produced and how to tackle some of them.
  
  Paper digest

• Adadan, E., Irving, K. E. and Trundle, K. C., (2009) Impacts of Multi-representational Instruction on High School Students' Conceptual Understandings of the Particulate Nature of Matter, International Journal of Science Education, 31 (13) 1743-1775.

  Teaching approaches continue to develop, and this paper compares two techniques to see if they can have an effect on reducing misconceptions about matter. The results show that both tested methods can successfully improve student understanding but the careful use of visual tools and appropriate simulations, selected after formative assessment, helps the most.
  
  Paper digest

• Lee, O., Eichinger, D. C., Anderson, C. W, Berkheimer, G. D. and Blakeslee, T. D., (1993) Changing Middle School Students’ Conceptions of Matter and Molecules, Journal of research in science teaching, 30 (3) 249-270.

• Talanquer, V. (2009) On Cognitive Constraints and Learning Progressions: The case of ''structure of matter'', International Journal of Science Education, 31 (15) 2123-2136.