Some students believe moving the observer's position will move the image produced by lens/lenses

Light, Sound and Waves


Resources to Address This

  • Teaching ray optics (11-16)

    Ref - Practical Physics;  Light and optics; Refraction of light;

    At introductory level, simple experiments can help students to realize that light travels in straight lines and that an object is seen when light from the object enters the eye. A lens bends light rays so that the rays pass through an image point and we think we see the object at that point.

    When doing some 'exploring' get the students to note that moving the observer does not move the image.

    View Resource


The following studies have documented this misconception:

  • Goldberg, F. M. and McDermott, L. C. () Student difficulties in understanding image formation by a plane mirror. The Physics Teacher, 24,


    Review sheet

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