1. Lead density high, electrical conductivity good, also is cheaper than the copper, therefore must suitablly make the electric wire compared to the copper
2. The lead is to the human body harmful heavy metal! . Because the micro lead can enter in food, then the human meets the chronicity to be poisoned, the reflection which changes is slow, heavy metal accumulation.
3. The mercury is virulent! The clinical thermometer and the human contact too intimately, use time exists riskThe clinical thermometer is the glass and the mercury mix, brittle, If has broken the thermometer, because mercury virulent, moreover is easy to volatilize, can create the danger. Also mercury melting point -38. 8 degree Celsius, quite are low...
4. Titanium quality of material firm, most essential is the density small, made the wing very to be light, uses in making the airplane the wing is again appropriate only.
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