Refraction
Image
Graphic:
The wave front model of refraction on an interface makes it clear why the direction of the sound propagation changes.
Type of media:
Image (93.5 kByte)
Last update:
2018-04-22
License:
This medium is made available under a CC BY-SA 4.0 international license.
What does this mean?
How to reference this medium
This medium is made available under a CC BY-SA 4.0 international license.
What does this mean?
How to reference this medium
Description:
When waves cross over from one medium to another, the speed at which the waves spread changes. Consequently, the wave normals of the incident and broken waves have different directions. With light waves, the change in the index of refraction at the boundary is the cause; with sound waves, it is the change in the density.
The graphic illustrates the case when the speed of propagation becomes slower at the transition from the first to the second medium: The wave is broken at the perpendicular of the boundary surface.
An explanation of this phenomenon is provided by the Huygens' Principle: Every point on a wave front is the starting point for a new wave, known as an “elementary wave". The enclosing end of the elementary wave creates the new wave front.
Information and ideas:
Refraction at boundaries also occurs with sound waves (for example, in the atmosphere at the transition from warm to cold layers of air).
Relevant for teaching:
Sound/acoustics: parameters
Vibrations and waves
The graphic illustrates the case when the speed of propagation becomes slower at the transition from the first to the second medium: The wave is broken at the perpendicular of the boundary surface.
An explanation of this phenomenon is provided by the Huygens' Principle: Every point on a wave front is the starting point for a new wave, known as an “elementary wave". The enclosing end of the elementary wave creates the new wave front.
Information and ideas:
Refraction at boundaries also occurs with sound waves (for example, in the atmosphere at the transition from warm to cold layers of air).
Relevant for teaching:
Sound/acoustics: parameters
Vibrations and waves
Related media:
There are no other media directly related to this file.
Learning resource type:
Information sheet
Subjects:
Physics
Grade levels:
Grade 7 to 9; Grade 10 to 13
School types:
Middle/high school; Vocational training
Keywords:
Light; Optical refraction; Optics; Sound; Wave (physics); Geometrical optics; Light (basic phenomenon); Refraction; Sound (basic phenomenon); Sound propagation; Sound wave; Wave optics
Bibliography:
Siemens Stiftung Media Portal
Author:
MediaHouse GmbH
Rights holder:
© Siemens Stiftung 2018