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Energía térmica

Diagrama:
Ecuaciones para la energía térmica de gases, así como la variación en función de la temperatura de la respectiva capacidad calorífica molar a volumen constante.

La energía térmica o interna de una sustancia es la suma de las energías cinéticas de sus átomos y moléculas. Esta energía puede medirse en forma de temperatura. Si se aplica calor a la sustancia, aumenta la velocidad de las partículas y, con ello, la temperatura. En los gases moleculares, la contribución de calor, además del movimiento de traslación, puede provocar también la excitación de otras formas de movimiento (rotación y oscilación). Esto se expresa en el desarrollo escalonado de la capacidad calorífica molar (diagrama derecho). La capacidad calorífica molar de una sustancia indica cuánta energía se debe aportar para aumentar en 1 °C la temperatura de 1 mol de una sustancia. En las sustancias gaseosas se cumple: si las partículas de gas solo tienen movimiento lineal (traslación), la cantidad de calor que se debe aportar para aumentar en 1 °C la temperatura del gas permanece constante 3R/2. En el caso de los gases moleculares, las moléculas comienzan a rotar a partir de una determinada temperatura. En esta región (incremento lineal en el diagrama) es necesario aportar más energía para aumentar la temperatura en 1 °C, ya que la energía no se convierte solo en el movimiento de traslación, sino también en la excitación de la rotación. Cuando todas las partículas se hallan en rotación, la energía que se debe aportar para aumentar la temperatura en 1 °C vuelve a ser constante 5R/2. El incremento en la transición de la rotación a la oscilación puede explicarse de manera análoga.

Información e ideas:
La figura de conjunto resume el tema de la energía calorífica en el ejemplo de los gases. En la directriz "¿Qué es la energía?? figuran explicaciones exhaustivas y aclaraciones sobre el calor en cuerpos sólidos.

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Detection reaction for unsaturated fats (5)

Photo:
After the test tube containing the butter is shaken for about three minutes, a blue coloration appears, as can be seen in the photo.

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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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The Ear, Hearing and Hearing Impairment;: Shark - hearing with the entire body

Graphic:
Slice image of the hearing organ (lateral-line organ) of a shark.

The shark as example of an animal that hears mainly with a part of its body surface.
Caption:
(a) pores
(b) inner canals filled with gelatinous fluid
(c) sensory cells containing the so called cilia
(d) nerves


Information and ideas:
The graphic is suitable for comparing the sensory cells in the human ear. Everyday context: methods of electroacoustic recording of sound with normal microphone and surface microphone.
Further information on the measuring method "audiometry" is available as information sheet on the media portal of the Siemens Stiftung.

Relevant for teaching:
Structure and function of a sensory organ
Reception of stimuli and processing of information
Senses discover the environment
Sound/acoustics: hearing range, hearing frequency limit

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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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Color mixing with light-emitting diodes

Photos:
Colors can be generated according to the additive color mixing process even with two unregulated colored LEDs.


Colors can be generated according to the additive color mixing process even with two unregulated colored LEDs.

Information and ideas:
Precise instructions and teaching ideas for building a variable LED color mixer can also be found on the media portal of the Siemens Stiftung.

Medientypen

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Lernalter

11-18

Schlüsselwörter

Color Theory Light Semiconductor

Sprachen

Englisch

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Siemens Stiftung

The Ear, Hearing and Hearing Impairment: With eyes blindfolded

Photo:
To illustrate the topic "Seeing with your ears?.

When the sense of sight is not working, another sense can replace the eyes. We pick up a lot of information about our environment from our ears and can thus, in part, at least, substitute the sense of sight.

Information and ideas:
For example, students can try out themselves on a listening walk whether they can guess where they are.

Relevant for teaching:
The human body
Structure and function of a sensory organ
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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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

; ; ;: Child with hearing aid

Graphic:
A boy and girl sitting at desks; the girl is wearing a hearing aid.

From the 2009 UN Convention on the Rights of Persons with Disabilities we can derive that children with and without disabilities should be taught together.
The graphic can serve as an example of how technical aids can be used in the case of disabilities.

Information and ideas:
Use graphic as introduction to topic of hearing damage. A handicap is visible to everyone (see hearing aid, compare with armband worn by the blind.)

Relevant for teaching:
Hearing damage, hearing impairment
How hearing works
Sound transduction
Impairment of sensory organs