A nursery school or kindergarten is an educational establishment for children aged three to five. The first was established in Germany in 1836 by Friedrich Froebel. Provision of nursery education varies widely between countries. In the UK, fewer than half of three and four-year olds have nursery education. In France, all children attend a state-run ecole maternelle from the age of three. In Japan, education is compulsory only from the age of six, but 90% of children attend a private nursery school from the age of three. The first kindergarten in Britain was opened by a German exile, Johannes Ronge, in Hampstead, London, in 1851, based on the philosophy of Froebel. Nursery education was extended in 1911 to working- class children by MargaretMcMillan and her sister Rachel, who worked in London's docklands. The Education Act of 1944 did not make nursery school compulsory. Increasing parental pressure from the 1960s led to a slow expansion, although at the end of the 1980s the UK still lagged behind most European countries in the provision of nursery-school places. Although 45% of three-and four-year-olds were in education in 1992, only half of these were in genuine nursery classes or schools; the rest were in primary classes. Research Nursery School
If a steelpoker is pushed into the fire and left there for a time the handle becomes warm. Heat travels through the metal by a process called conduction. This process is complex. It differs between metals and non-metals. When a metal is heated the free electrons which it contains begin to move faster, i.e., their kinetic energy increases. The hot electrons then drift towards the cooler parts of the metal and at the same time there is a drift of slower-moving (cooler) electrons in the reverse direction. In those substances where no free electrons are present the process of conduction is entirely different. In such cases the heat energy is conveyed by longitudinal waves, similar to sound waves, but of considerably higher frequency. These waves are transmitted in tiny energy packets called 'phonons'. Most metals are good conductors of heat; silver and copper are exceptionally good. On the other hand, substances such as cork, wood, cotton and wool are bad conductors. Both good and bad conductors have their uses.
The best kettles, other than electric kettles, are made of copper, since heat is conducted most rapidly through this metal. The 'bit' of a soldering iron is also made of copper, so that when its tip is cooled through contact with the work, heat is rapidly conducted from the body of the bit to restore the temperature of the tip and maintain it above the melting point of solder. Bad conductors have a very wide application. Beginning with our personal comfort, we prevent loss of heat from ourselves by a covering of poorly conducting material. Textiles are bad conductors of heat, since they are full of tiny pockets of air enclosed by the fibres of the material. Air, in common with all gases, is a very bad conductor of heat. It is usual to say that wool is warmer than cotton. Technically, of course, we imply that it has a lower thermal conductivity than cotton. A stone floor feels cold to the bare feet, but a carpet on the same floor feels warm. This difference arises from the fact that stone is a better conductor of heat than a carpet. To begin with both the stone floor and the carpet are at the same temperature. Since the feet are warmer than either, heat tends to flow from the feet. Stone, being the better conductor, conveys heat away from the feet more rapidly than the carpet. Consequently, the feet feel cold on the stone but warm on the carpet. Precisely the same effect is experienced when handling a garden fork in winter. The iron part of the fork feels cold, but the wooden handle warm.
Loss of heat by conduction through the walls of an oven is reduced by constructing it with double walls. The space between is packed with slag wool or glass fibre. These substances are not only very poor conductors but also have the merit of being non-inflammable. Material of low thermal conductivity used for the purpose of preventing heat loss is called lagging. Another example is the covering of hot-water storage tanks and pipes with a layer of plaster mixed with asbestos or other insulating material. Similarly, cold-water pipes may be lagged with strips of felt or sacking to prevent freezing during very cold weather. Research Transmission of Heat
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Research Nursery School
