The drastic change is the detonation this concept core, is also possibly most difficult to let the human accept. A detonation this word by the widespread application was in the first 1970s, it is used for to describe the Northeastern United States old city Caucasian to move to abundance suddenly the suburb the phenomenon. 1 sociologists discovered that when moves into some inhabited area the black proportion achieves a ghd south africa sale specific spot - - 20%, the entire community quilt “the detonation”: Still lived in this community's Caucasians will leave immediately. Before the detonation spot is the qualitative change approaches a key spot, looks like the boiling point and the critical point. Before the 1990s the early New York petty crime dropped suddenly, had a detonation spot, before the free time step gentleman walking shoe is in fashion once again, also some detonation spot, just like each new technology is introduced in the process some detonation spot. in 1984 Sharp Corporation promoted when for the first time the low price facsimile machine has sold 80,000. Afterward three years, facsimile machine's sales number rises with steady steps gradually. Person's who quantity to 1987, had the facsimile machine already sufficiently let each people think that he should have a facsimile machine. in 1987 has become the detonation spot. In the past has sold 1,000,000, up to 1989, also has sold 2,000,000 new facsimile machines. The handset sale is also following the similar path. The entire the 1990s, the handset in toward was more exquisite, is cheaper, a service better development, until 1998, this technology has achieved the detonation spot, each people had a handset suddenly. All popular tides have a detonation spot. University of Illinois's sociologist Jonathan? Krey has made one item about the community in the role model (role models) quantity the research - - these role model ghd specials south africa which the young people affects to the community in including counts Investigation Bureau to recognize has the high social position crowd - - specialists, manager and the teacher. When the role model accounts for the community population between 5%~40%, community young people's early pregnancy rate and drop-out rate not wide difference. But, when the role model occupies the ratio is lower than 5%, the question is detonated. For instance, when the role model accounts for the ratio to drop a percentage point, from the drop, the black school-age child's drop-out rate will double many. Lights in this detonation, the underage young girl's early pregnancy rate also doubled and re-doubled nearly increases - - when has not achieved detonation, the early pregnancy rate maintains invariable nearly. We usually recognized depending on the intuition that the community environment's change and the social question's reduction is one slow and the stable process. But sometimes they not according to this rhythmic ghd africa variation; When arrival detonation, the school will lose the control to the student, the family life can collapse immediately.