Some students struggle to draw ray diagrams showing refraction when the boundary is depicted as vertical if they have been introduced to the concept with horizontal boundaries.

Light, Sound and Waves


Diagnostic Resources

The following worksheets may help to identify whether students hold this particular misconception.

For more information, see the University of York BEST website.

Resources to Address This

  • Thinking about actions to take: Seeing With Light (11-14)

    Ref - Li03TL06

    This resources lists approaches to improve teaching.

    • exploring the phenomenon of refraction through many different examples
    • developing more complex examples on the foundations of an account of the simple phenomena

    Make sure some of the examples include a vertical boundary.

    View Resource
  • Episode 317: Reflection and refraction of waves (16-19)

    Ref - TAP; Teaching vibrations and waves; Reflection and refraction;

    This episode starts from the phenomenon of refraction and moves on to Snell’s law.

    Make sure some of the examples include a vertical boundary.

    View Resource


The following studies have documented this misconception:

  • Andersson, B and Kärrqvist, C. () How Swedish pupils, aged 12‐15 years, understand light and its properties European Journal of Science Education, 5 (4),


    DOI: 10.1080/0140528830050403.

    Review sheet

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