Research
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Gaia hypothesis
The study of planetary habitability is partly based upon extrapolation from knowledge of the Earth 's conditions, as the Earth is the only planet currently known to harbour life The Gaia hypothesis , also known as Gaia theory or Gaia principle , proposes that organisms interact with their inorganic surroundings on Earth to form a self-regulating , complex system that contributes to maintaining the conditions for life on the planet.
A block of aerogel in hand Aerogel is a synthetic porous ultralight material derived from a gel , in which the liquid component of the gel has been replaced with a gas . The result is a solid with extremely low density [ 1 ] and thermal conductivity . Nicknames include "frozen smoke", [ 2 ] "solid smoke", "solid air" or "blue smoke" owing to its translucent nature and the way light scatters in the material; however, it feels like extruded polystyrene ( Styrofoam ) to the touch. Aerogel was first created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid in "jellies" with gas without causing shrinkage. [ 3 ] [ 4 ] Aerogels are produced by extracting the liquid component of a gel through supercritical drying .
Aerogel
Se donner le mot :: Expressions idiomatiques
Bienvenue Christopher Hal l et Pierre Verville vous entraînent dans leur monde rocambolesque à la découverte des expressions idiomatiques. Se donner le mot , c'est l'apprentissage du français à l’aide de 52 expressions idiomatiques. C'est l'outil par excellence pour faire des découvertes linguistiques dans un cadre créatif, interactif et ludique. Résolution d'écran minimale : 1024x768.
Anime