absorption


absorption
/ab sawrp"sheuhn, -zawrp"-/, n.
1. the act of absorbing.
2. the state or process of being absorbed.
3. assimilation; incorporation: the absorption of small farms into one big one.
4. uptake of substances by a tissue, as of nutrients through the wall of the intestine.
5. a taking in or reception by molecular or chemical action, as of gases or liquids.
6. Physics. the removal of energy or particles from a beam by the medium through which the beam propagates.
7. complete attention or preoccupation; deep engrossment: absorption in one's work.
[1590-1600; < L absorption- (s. of absorptio), equiv. to absorpt(us), ptp. of absorbere to ABSORB + -ion- -ION]

* * *

Transfer of energy from a wave to the medium through which it passes.

The energy of the wave can be reflected, transmitted, or absorbed. If the medium absorbs only a fraction of the energy, it is said to be transparent to that energy. When all energy is absorbed, the medium is opaque. All substances absorb energy to some extent. For instance, the ocean appears transparent to sunlight near the surface, but becomes opaque with depth. Substances absorb specific types of radiation. Rubber is transparent to infrared radiation and X rays, but opaque to visible light. Green glass is transparent to green light but absorbs red and blue light. Absorption of sound is fundamental to acoustics; a soft material absorbs sound energy as the waves strike it.

* * *

      in wave motion, the transfer of the energy of a wave to matter as the wave passes through it. The energy of an acoustic, electromagnetic (electromagnetic radiation), or other wave is proportional to the square of its amplitude—i.e., the maximum displacement or movement of a point on the wave; and, as the wave passes through a substance, its amplitude steadily decreases. If there is only a small fractional absorption of energy, the medium is said to be transparent to that particular radiation, but, if all the energy is lost, the medium is said to be opaque. All known transparent substances show absorption to some extent. For instance, the ocean appears to be transparent to sunlight near the surface, but it becomes opaque with depth.

      Substances are selectively absorbing—that is, they absorb radiation of specific wavelengths. Green glass is transparent to green light but opaque to blue and red; hard rubber is transparent to infrared and X rays but opaque to visible light. Thus, radiation of an unwanted wavelength may be removed from a mixture of waves by letting them pass through an appropriate medium. Those substances that are designed to absorb a particular wavelength or band of wavelengths are called filters.

 As radiation passes through matter, it is absorbed to an extent depending on the nature of the substance and its thickness. A homogeneous substance of a given thickness may be thought of as consisting of a number of equally thin layers. Each layer will absorb the same fraction of the energy that reaches it. The diagram—> shows a beam of waves passing from right to left through a series of layers (d1, d2, d3) of a medium. If the fractional absorption is taken as 33 percent, or 1/3, after the beam passes through the first layer d1, its initial energy (E0) will be reduced to E0/3. One-third the energy E0/3 will be absorbed passing through layer d2, and the beam will enter layer d3 with energy 1/3 (E0/3), or (E0/9). Similarly, each successive layer absorbs one-third of the energy it receives. Thus for radiation of a given wavelength, an infinitesimally thin layer will reduce the energy of a wave by a fractional amount that is proportional to the thickness of the layer. The change in energy as the wave passes through a layer is a constant of the material for a given wavelength and is called its absorption coefficient.
 

* * *


Universalium. 2010.

Synonyms:

Look at other dictionaries:

  • absorption — [ apsɔrpsjɔ̃ ] n. f. • 1586; lat. absorptio 1 ♦ Action d absorber. L absorption de l eau par les terrains perméables; d une crème par la peau. Physiol. Absorption digestive : passage des produits de la digestion dans le sang et la lymphe, au… …   Encyclopédie Universelle

  • Absorption [1] — Absorption. Die Absorption der Gase durch feste Körper und Flüssigkeiten ist eine Wirkung derselben Molekularkräfte, welche die Erscheinungen der Adhäsion und der Lösung hervorbringen. In vielen Fällen, ohne daß feste stöchiometrische Beziehungen …   Lexikon der gesamten Technik

  • Absorption — may refer to:Chemistry and biology*Absorption (chemistry), absorption of particles of gas or liquid in liquid or solid material *Absorption (skin), a route by which substances can enter the body through the skin *Absorption (pharmacokinetics),… …   Wikipedia

  • Absorption — oder absorbieren (von lateinisch absorptio bzw. absorbere, „(ab /auf)saugen“) steht für: Absorption (Chemie), die Aufnahme eines Stoffes durch einen anderen Absorption (Physik), verschiedene Transformationsvorgänge, vor allem in der Akustik;… …   Deutsch Wikipedia

  • Absorption [2] — Absorption, photochemische. Da Licht, das auf irgend welche Substanzen chemisch einwirkt, dabei offenbar eine gewisse Arbeit leistet, so ist zu erwarten, daß es stärker absorbiert wird, als wenn keine chemische Einwirkung stattfindet. Ueber die… …   Lexikon der gesamten Technik

  • Absorption — Ab*sorp tion, n. [L. absorptio, fr. absorbere. See {Absorb}.] 1. The act or process of absorbing or sucking in anything, or of being absorbed and made to disappear; as, the absorption of bodies in a whirlpool, the absorption of a smaller tribe… …   The Collaborative International Dictionary of English

  • absorption — ab·sorp·tion n: the application to the states of rights guaranteed by the U.S. Constitution while Powell [ v. Alabama ] was sometimes described as having absorbed the right to counsel, the Court there clearly limited any such absorption W. R.… …   Law dictionary

  • Absorption — (lat., »Ein , Aufsaugung«). 1) Die A. der Gase durch Flüssigkeiten ist im allgemeinen bei niederer Temperatur größer als bei höherer und wird sehr stark durch den Druck beeinflußt. 1 Lit. Wasser verschluckt bei 15° stets 1 L. Kohlensäure, unter… …   Meyers Großes Konversations-Lexikon

  • Absorption — (lat., »Aufsaugung«), die Eigenschaft fester und flüssiger Körper, Gasarten in sich aufzunehmen oder auf ihrer Oberfläche zu verdichten. Gut ausgeglühte, fein poröse Holzkohle hat die Fähigkeit, Gase einzusaugen, in sehr hohem Grade;… …   Kleines Konversations-Lexikon

  • absorption — [n1] assimilation, incorporation consumption, digestion, drinking in, exhaustion, fusion, imbibing, impregnation, ingestion, inhalation, intake, osmosis, penetration, reception, retention, saturation, soaking up, suction, taking in; concepts… …   New thesaurus

  • Absorption [3] — Absorption der Sonnenwärme, s. Geothermik …   Lexikon der gesamten Technik


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.