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Siemens Stiftung

The Ear, Hearing and Hearing Impairment: Differentiated frequency ranges in the cochlea

Labeled graphic:
Position of the receptors for tones of varying frequencies in the spiral canal of the human cochlea.

Frequencies between 16 hertz (hertz = vibrations per second, abbr.: Hz) and 20,000 Hz can be heard by the human ear.
To differentiate these frequencies, the receptors for high tones are at the beginning of the canal, those for the low tones at the apex of the cochlea.

Information and ideas:
The illustration is suitable for explaining or revising fundamentals of Physics like sound, frequency and vibrations.
Usable in a worksheet, for work together on the digital projector, or as an overhead transparency.

Further information regarding this graphic is available on the media portal of the Siemens Stiftung.

Relevant for teaching:
The human body
Structure and function of a sense organ
Perception of sound
Human hearing ability
Communication and understanding

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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

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Siemens Stiftung

The Ear, Hearing and Hearing Impairment: Sense organs - sense of feeling

Graphic:
How sensitively our skin reacts to temperatures can be seen in the sauna. After the heat, the cold gets our blood circulation going!

The skin gives us information about temperatures via receptors. As a rule, the heat in the sauna makes our blood pressure go down. The subsequent sensation of cold on the skin does not just stimulate the peripheral blood circulation. A reflex reaction via the autonomic nervous system causes our blood pressure to rise to the normal level again as well.

Information and ideas:
Use picture to introduce topic with the question "What can we feel with our skin?", e.g. cold, heat, wind etc.

Relevant for teaching:
The human body
Structure and function of a sensory organ
Reception of stimuli and processing of information
Senses discover the environment

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Siemens Stiftung

Speech signal - individual word

Chart:
Screenshot of the oscillographic curve of the spoken word "dogs".

Speech sounds are fluctuating sound signals where the composition of frequencies changes all the time.
Aperiodical overlap periodical parts. Unlike noises, some of which have similar frequency curves, sound in speech is always the carrier of meaning or of messages sent out by the speaker. Other noises like smacking of lips, hissing, rhythms, basic pitch are typical of the individual (acoustic fingerprint) but not essential for the speech content!

Information and ideas:
Supplementary to worksheets and transparencies.

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

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Siemens Stiftung

Speech recognition sentence - syllable - phoneme

Chart:
The components of speech, from phoneme to sentence presented visually.

The graphic shows the oscilloscope curve of the spoken sentence "It?s raining cats and dogs" and excerpts from the units from which speech is composed: sentence, word, phoneme.

Information and ideas:
Speech recognition and speech synthesis are very topical themes in the field of information and communication technology.
Further information on this graphic is available as information sheet on the media portal of the Siemens Stiftung.

Relevant for teaching:
The human body
Structure and function of a sense organ
Reception of impulses and information transmission
Sensory perception

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Siemens Stiftung

Microphone - transparent

Graphic:
With a moving coil microphone (dynamic microphone), the coil moves in "time" with the sound and produces a tone-frequency current.

In a microphone the mechanical energy of the sound waves is transduced into electric energy. From the mechanical vibrations the microphone produces an electric signal of the same frequency and amplitude.

Information and ideas:
Explanation of the process of sound transduction as it occurs in the inner ear of a human being using a technical device familiar to the students.

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

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Siemens Stiftung

Injuries to the ear through violence

Photo:
"Ouch!" Pulling at somebody's ears not only hurts, it can be dangerous and injure the ear both internally and externally!

Do not pull hard at somebody's ears or clip anyone round the ears because that can damage the sensitive ear.

Information and ideas:
A situation that can be observed in the school playground or at a children's playground. The photo can be used to start talking about the topic of how to protect the ears.

Possible questions:
What am I allowed to do to my ears?
What should I not do?
Why can a joke end up having serious consequences?

Relevant for teaching:
Hearing defects, hearing impairment
Personal health care

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Siemens Stiftung

Guitar, a classical string instrument

Photo:
Sound is produced by plucking strings and their vibrations are reflected by the resonance of the guitar body.

The vibration of the strings is transmitted to the body (soundboard) of the guitar which in turn vibrates and stimulates the air in the hollow body to vibrate itself. Finally a much bigger volume of air is now vibrating, the sound of the strings is much more clearly audible.

Information and ideas:
Guitar, violin and piano are good examples to illustrate the production of sound through vibrating objects on the one hand and, on the other hand, to show the importance and function of resonance bodies.

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

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Siemens Stiftung

How long will our energy sources last?

Chart:
A bar chart shows an overview of the remaining years of use of primary energy sources.

Of the fossil energy sources, petroleum will be the first to run out. What is the situation for the other fossil energy sources? Can new technologies delay the point in time when they run out? And is it really true that renewable energy sources never run out?
The time axis has a logarithmic scale.

Information and ideas:
Students learn that the logarithmic scale represents numbers ranging over several powers. More in-depth information regarding how long energy sources will last is provided in the "An overview of energy sources? information sheet.


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Siemens Stiftung

The Ear, Hearing and Hearing Impairment: Speech as highly complex sound signal

Graphic:
Oscillographic curve of the spoken sentence "It's raining cats and dogs".

Speech sounds are fluctuating sound signals where the composition of frequencies changes all the time.
Aperiodical overlap periodical parts. Unlike noises, some of which have similar frequency curves, sound in speech is always the carrier of meaning or of messages sent out by the speaker. Other noises like smacking of lips, hissing, rhythms, basic pitch are typical of the individual (acoustic fingerprint) but not essential for the speech content!

Information and ideas:
Supplementary to worksheets and transparencies.

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