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Siemens Stiftung

Waves in the water

Photo:
If you want to give the students an initial impression of sound waves, the propagation of waves in water is very useful.

When a stone is thrown into the water, concentric circles spread out from the spot where the stone hit the water. Sound waves move away from the source of sound in a similar way.

Information and ideas:
The well-known photo may be a help for students to picture the propagation of sound waves in their minds. (Strictly speaking a water wave and a sound wave differ with respect to the direction of the vibration - transversal and longitudinal respectively!)

Relevant for teaching:
Acoustic phenomena
Vibrations and waves

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Siemens Stiftung

Ultrasound materials testing - principle

Labeled graphic:
From the delay differences of the echoes recorded, layer thicknesses, errors and consistency can be calculated with oscilloscope graphs.

In engineering the checking of the quality of materials is an important task. A cheap way of testing materials where the material to be tested is not destroyed is based on the reflection of sound on interfaces.

Information and ideas:
These tasks are good for showing how behaviour of sound is used in practice.
Furthermore, internet research is good for explorative learning.

Relevant for teaching:
Sound/acoustics: parameters
Vibration and waves

Medientypen

Bild

Lernalter

11-18

Schlüsselwörter

Electroacoustics Sound Wave (physics)

Sprachen

Englisch

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Siemens Stiftung

The Ear, Hearing and Hearing Impairment: Acoustic scattering

Graphic:
Acoustic scattering. One of several ways sound waves react when they hit an obstacle.

Scattering is a reflection of small structures in no particular preferred direction. It is very much dependent on frequency.

Information and ideas:
Can be checked with the students in an experiment.

Relevant for teaching:
Sound/acoustics: parameters
Vibrations and waves

Übung

Siemens Stiftung

Types of sound (matching exercise)

Matching exercise (with sound):
Students identify and name the various types of sound from sample audio clips - verbally and by matching the corresponding sound curve (oscillogram).

The oscillograms can be matched to the individual sample audio clips by dragging and dropping.
The type of sound can be named by dragging and dropping or manually on the interactive whiteboard.

Medientypen

Übung

Lernalter

11-18

Schlüsselwörter

Sound Wave (physics)

Sprachen

Englisch

Dieses Material ist Teil einer Sammlung

Anderer Ressourcentyp

Siemens Stiftung

How is sound produced?

Interactive graphic:
The production of sound is illustrated. The path of sound from the sound source via the sound medium to the sound receiver is described step by step.

An oscillating loudspeaker diaphragm shows the pulses transmitted to the air particles. Further propagation by means of air compression and air rarefaction as a longitudinal wave is shown graphically.


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Video

Siemens Stiftung

The Ear, Hearing and Hearing Impairment;: Tuning fork as "simple? sound

Video (00:10 minutes):
Example of a simple periodic sound signal is the relatively pure sound of a tuning fork. The video shows the oscilloscope graph!

The pure periodic sound is the simplest sound event. It corresponds to a regular sine vibration (= harmonic vibration) of pure frequency. The sound of a tuning fork is the nearest of all non-synthetic sound sources to this ideal.

Information and ideas:
Suitable for demonstration purposes but also good for self-study on the part of the students. Idea: show the video without sound to begin with. The students should then guess what sort of noise/sound it might be.

Relevant for teaching:
Acoustic phenomena
Sound/acoustics: parameters
Communication and understanding
Vibrations and waves

Medientypen

Video

Lernalter

11-18

Schlüsselwörter

Sound Wave (physics)

Sprachen

Englisch

Dieses Material ist Teil einer Sammlung

Audio

Siemens Stiftung

The Ear, Hearing and Hearing Impairment;: Tuning fork as "simple" sound

Recording:
Example of a simple periodic sound signal is the relatively pure sound of a tuning fork.

The pure periodic sound is the simplest sound event. It corresponds to a regular sine vibration (= harmonic vibration) of pure frequency. The sound of a tuning fork is the nearest of all non-synthetic sound sources to this ideal.

Information and ideas:
Recording to illustrate different sorts of sound (or students have to identify them).

Relevant for teaching:
Sound/acoustics: parameters
Communication and understanding
Vibrations and waves
Acoustic phenomena


Dieses Material ist Teil einer Sammlung

Anderer Ressourcentyp

Siemens Stiftung

The Ear, Hearing and Hearing Impairment;: Sound propagation and obstacles

Information sheet:
What happens when sound hits an obstacle? The wave nature of sound is explained.

Sound waves propagate concentrically or spherically. A free or undisturbed sound field is one where there are no obstacles in the path of the sound waves. In everyday life, however, the sound field is usually disturbed or blocked by obstacles, for example, walls or people.
There are a number of ways a sound can behave when it hits an obstacle: refraction, reflection, dispersion, absorption, diffraction. All these possibilities arise ultimately because of the wave nature of sound.

Information and ideas:
This information sheet provides a good overview of the most important basic concepts of the wave nature of sound.

Relevant for teaching:
Sound/acoustics: parameters
Vibrations and waves


Dieses Material ist Teil einer Sammlung

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Siemens Stiftung

The Ear, Hearing and Hearing Impairment: Sound absorption

Graphic:
If sound waves strike an obstacle with a corresponding material structure, they are absorbed, i.e. the entire mechanical energy of the sound is converted into thermal energy.

This effect is enhanced by sound barrier walls made of porous materials. By means of multireflection and dispersion, the passage of sound in such materials is extended considerably. The sound peters out.

Information and ideas:
Reference to students' everyday world: silence after snowfall.
Can be checked with the students in an experiment.

Relevant for teaching:
Sound/acoustics: parameters
Vibrations and waves

Anderer Ressourcentyp

Siemens Stiftung

The Ear, Hearing and Hearing Impairment: Sound (link list)

Link list:
Many interesting links regarding the topic "Sound".

Information and ideas:
Suitable as a source for internet inquiry for the teacher and students.


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