Mdestructive Techniques Involving at www.japanese-home-gardens.com

Although mdestructive techniques involving infrared and :!traviolet examination or photography have for ;.ears been applied to erasure problems and to ink and paper analysis, newer procedures that utilize infrared luminescence are now being used to differentiate ink and to decipher erasures.

Minerals are the building blocks of rocks. Some rocks are made up of only one mineral while others contain many of them. Only rarely do useful minerals occur in sufficient concentrations to make commercial exploitation worthwhile [Key]. Increasingly sophisticated technology means, however, that deposits that were uneconomic to work a few years ago can now be profitably exploited. New techniques have also made it possible to re-work the waste heaps of some mines. Scarcity due to an increased demand or to depletion of richer reserves can also make the extraction of low-grade ores profitable without necessarily involving a change of the basic mining techniques being employed.

So far, we have described a model which has proved its worth in numerous schools; but there are other ideas and techniques which should be considered. These can supplement our main model, and perhaps in certain areas replace it. The variations discussed in this chapter are in no way an exhaustive review of all the initiatives that teachers have taken, but they are intended to demonstrate the great variety of forms that involving parents in education can take, many of them fun as well as rewarding.