Refraction through a rectangular block (including wave front diagrams)
I can describe what refraction is, draw accurate diagrams of refraction and use the idea of wavefronts to explain what causes refraction.
Refraction through a rectangular block (including wave front diagrams)
I can describe what refraction is, draw accurate diagrams of refraction and use the idea of wavefronts to explain what causes refraction.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Refraction is when waves travel from one transparent medium to another, causing a change in direction.
- When waves slow down, they turn towards the normal line (angle of incidence > angle of refraction).
- When waves speed up, they turn away from the normal line (angle of incidence < angle of refraction).
- Refraction can be investigated using a clear rectangular block, ray box and narrow slit, pencil, paper and a protractor.
- Refraction occurs when one side of a wavefront enters the new medium before the other, causing a change in wave speed.
Keywords
Refraction - Refraction occurs when waves travel from one transparent medium to another, causing a change in wave speed and direction.
Normal - The normal is an imaginary line drawn at 90° to a surface.
Angle of incidence - The angle of incidence is the angle between the incident ray and the normal.
Angle of refraction - The angle of refraction is the angle between the refracted ray and the normal.
Wavefront - Wavefronts are lines drawn to represent the peaks of a wave.
Common misconception
Pupils sometimes rote-learn what specific examples of refraction look like, rather than developing a more general understanding of the direction waves turn based on changes in wave speed.
Teach pupils the general theory of refraction and apply it to a variety of different examples where wave speed changes (e.g. sound waves refract in the opposite direction to light at an air-glass boundary due to the different wave speeds).
To help you plan your year 11 physics lesson on: Refraction through a rectangular block (including wave front diagrams), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 11 physics lesson on: Refraction through a rectangular block (including wave front diagrams), download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 physics lessons from the Electromagnetic waves unit, dive into the full secondary physics curriculum, or learn more about lesson planning.
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Lesson video
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Starter quiz
6 Questions
loses its brightness as it passes through the object
passes through the object
bounces off the surface of the object
Exit quiz
6 Questions
