Foam

A foam is a substance that is formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the regions of gas.

An important division of solid foams is into closed-cell foams and open-cell foams. In a closed-cell foam, the gas forms discrete pockets, each completely surrounded by the solid material. In an open-cell foam, the gas pockets connect with each other. A bath sponge is an example of an open-cell foam: water can easily flow through the entire structure, displacing the air. A camping mat is an example of a closed-cell foam: the gas pockets are sealed from each other so the mat cannot soak up water.

Foams are examples of dispersed media. In general, gas is present in large amount so it will be divided into gas bubbles of many different sizes (the material is polydisperse) separated by liquid regions which may form films, thinner and thinner when the liquid phase is drained out of the system films. When the principal scale is small, i.e. for a very fine foam, this dispersed medium can be considered as a type of colloid.

Foam (disambiguation)

Foam may refer to:

See also

Gum (botany)

Gum is a sap or other resinous material associated with certain species of the plant kingdom. This material is often polysaccharide-based and most frequently is associated with woody plants, particularly under the bark or as a seed coating. The polysaccharide material is typically of high molecular weight and most often highly hydrophilic or hydrocolloidal.

As seed coating

Many gums occur as seed coatings for plant species; the adaptive purpose of some of these gummy coatings is to create a time delayed germination of certain flora seeds. An example of such a gummy coating occurs in the case of Western poison oak, a widespread shrub in western North America.

See also

Line notes

5 (gum)

5 is a brand of sugar-free chewing gum that is manufactured by the Wrigley Company. The name "5" hints at the five human senses (with the ad slogan "Stimulate Your Senses" and "Everybody Experiences it Differently"). 5 gum was introduced to United States markets in March 2007, in Canada in January 2008, in Russia, Europe and Australia in 2009, in China, India, Italy, Israel, Thailand, and Malaysia in 2010.

Products

The brand features 24 flavours of chewing gum, all of which are available in the United States with the exception of Cirrus, Zephyr and Evolution. The first three flavors introduced were Peppermint, Spearmint, and Cinnamon; second came Tropical and Berry; and in 2009, Winter mint and Bubble. In March 2010, two new flavors, both named "React" were introduced in the United States along with the slogan: "Everyone Experiences It Differently." "React" comes in both mint and fruit flavors. It was released in Australia in March 2011. 5 also offers a watermelon flavor called "Prism", a Green apple flavor called "Vortex" and a sour tropical flavor called "Swerve".

NGC 6334

NGC 6334 (also known as the Cat's Paw Nebula, Bear Claw Nebula and Gum 64) is an emission nebula and star-forming region located in the constellation Scorpius. It was discovered by astronomer John Herschel in 1837, who observed it from the Cape of Good Hope in South Africa.

Gallery

This portrait of NGC 6334 was created from images taken with the Wide Field Imager instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile.

This portrait of NGC 6334 was created from images taken with the Wide Field Imager instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile.

Wide view centred on NGC 6334.

Wide view centred on NGC 6334.

ESO's VISTA infrared view of NGC 6334.

ESO's VISTA infrared view of NGC 6334.

Play media

This video compares the near-infrared and submillimetre views of the star formation region.

This video compares the near-infrared and submillimetre views of the star formation region.

References

External links