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.

Creative Commons

Creative Commons (CC) is a non-profit organization devoted to expanding the range of creative works available for others to build upon legally and to share. The organization has released several copyright-licenses known as Creative Commons licenses free of charge to the public. These licenses allow creators to communicate which rights they reserve, and which rights they waive for the benefit of recipients or other creators. An easy-to-understand one-page explanation of rights, with associated visual symbols, explains the specifics of each Creative Commons license. Creative Commons licenses do not replace copyright, but are based upon it. They replace individual negotiations for specific rights between copyright owner (licensor) and licensee, which are necessary under an "all rights reserved" copyright management, with a "some rights reserved" management employing standardized licenses for re-use cases where no commercial compensation is sought by the copyright owner. The result is an agile, low-overhead and low-cost copyright-management regime, profiting both copyright owners and licensees. Wikipedia uses one of these licenses.

Nursery rhyme

A nursery rhyme is a traditional poem or song for young children in Britain and many other countries, but usage only dates from the late 18th /early 19th century. In North America the term Mother Goose Rhymes, introduced in the mid-18th century, is still often used.

History

Lullabies

The oldest children's songs of which we have records are lullabies, intended to help a child sleep. Lullabies can be found in every human culture. The English term lullaby is thought to come from "lu, lu" or "la la" sound made by mothers or nurses to calm children, and "by by" or "bye bye", either another lulling sound, or a term for good night. Until the modern era lullabies were usually only recorded incidentally in written sources. The Roman nurses' lullaby, "Lalla, Lalla, Lalla, aut dormi, aut lacta", is recorded in a scholium on Persius and may be the oldest to survive.

Many medieval English verses associated with the birth of Jesus take the form of a lullaby, including "Lullay, my liking, my dere son, my sweting" and may be versions of contemporary lullabies. However, most of those used today date from the 17th century. For example, a well known lullaby such as "Rock-a-bye, baby on a tree top", cannot be found in records until the late-18th century when it was printed by John Newbery (c. 1765).

Kevin MacLeod

Kevin MacLeod or Kevin McLeod may refer to:

See also