Phonons, rotons, and layer modes of liquid 4He in aerogel

Fak1, Plantevin, Glyde

  • 1Departement de Recherche Fondamentale sur la Matiere Condensee, SPSMS/MDN, CEA Grenoble, 38054 Grenoble, France.

Physical Review Letters
|October 21, 2000
PubMed

Related Concept Videos

Molecular Comparison of Gases, Liquids, and Solids02:26

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no regular arrangement (no fixed shape); in a gas, they are far apart with no regular arrangement (no fixed shape). Particles in a solid vibrate about fixed positions (cannot flow) and do not generally move in relation to one another; in a liquid, they move past each other (can flow) but remain in essentially constant contact; in a gas, they move...
Phase Transitions: Vaporization and Condensation02:39

Phase Transitions: Vaporization and Condensation

The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
Speed of Sound in Solids and Liquids00:51

Speed of Sound in Solids and Liquids

Most solids and liquids are incompressible—their densities remain constant throughout. In the presence of an external force, the molecules tend to restore to their original positions, which is only possible because the constituents interact. The interactions help the constituents pass on information about external disturbances, like sound waves. Therefore, sound waves travel faster through these media. Compared to solids, the constituents in a liquid are less tightly bound. Thus, sound waves...
States of Matter01:20

States of Matter

Solids, liquids, and gases are the three states of matter commonly found on Earth. A solid is rigid and possesses a definite shape. A liquid flows and takes the shape of its container, except it forms a flat or slightly curved upper surface when acted upon by gravity. Both liquid and solid samples have volumes nearly independent of pressure. A gas takes both the shape and volume of its container.
Scientists have discovered a fourth state of matter, plasma, that occurs naturally in the interiors...
Deriving the Speed of Sound in a Liquid01:09

Deriving the Speed of Sound in a Liquid

As with waves on a string, the speed of sound or a mechanical wave in a fluid depends on the fluid's elastic modulus and inertia. The two relevant physical quantities are the bulk modulus and the density of the material. Indeed, it turns out that the relationship between speed and the bulk modulus and density in fluids is the same as that between the speed and the Young's modulus and density in solids.
The speed of sound in fluids can be derived by considering a mechanical wave propagating...
Liquid–Solid Solutions01:29

Liquid–Solid Solutions

The process of a solid dissolving in a liquid to form a solution is governed by the solubility limit, which is the maximum amount of the solid substance, or solute, that can be dissolved in a specific volume of the liquid or solvent. As the solute dissolves, it reaches a point where no more solute can be dissolved at a given temperature - this is known as the saturation point. However, if further solute is added and it manages to dissolve, the solution becomes supersaturated. Supersaturated...