Fireplace crystals

Applying ideas Some stores sell jars of fireplace crystals. When sprinkled on a log, these crystals make the flames blue, red, green, and violet. Explain how these crystals can change the flame s color. What ingredients would you expect the crystals to contain ... 

Fireplace crystals May oontain salts of copper, selenium, arsenic, and antimony. Small amounts oan oause irritation to the mouth orstomach. (Larger ingestions oould oohoelvably result in heavy metal poisoning see specific heavy metal.)... 

Another glance into the atelier revealed the Maestro slumped over the crystal, exhausted. Clairvoyance always smites him with a fearful headache. Between us, Fulgentio and I helped him to the chair by the fireplace. I poured him a glass of wine and he took it in shaky hands. 

He ignored the velvet cloth over the crystal ball, as if to imply that he would not be distracted by hocus-pocus. He passed the fireplace and came to the big double desk near the windows, littered on the Maestro s side with books and on mine with the packets of reagents I had left there, plus the letter I had been working on when I was sent shopping. Sciara reached for the paper. 

We focus on a node W, saw the crystal along the plane that dissects (symmetrically) the distance to a nearest-neighbor node, throw the part that does not contain W into the fireplace, and then repeat the procedure until we are left with a solid containing W. This solid represents the First BrUlouin Zone (FBZ). 

Have you ever bought color crystals for your fireplace — to make flames of different colors Or have you ever watched fireworks and wondered where the colors came from ... 

As was remarked at the beginning of this chapter, the example of a jigsaw puzzle shows us that a parallelepiped unit cell is not the only choice. Now, we will profit from this extra freedom and will define the so-called Wigner-Seitz unit cell. Here is the prescription for how to construct it (Fig. 9.5) We focus on a node W, saw the crystal along the plane that dissects (symmetrically) the distance to a nearest-neighbor node, throw the part that does not contain W into the fireplace, and then repeat the procedure until we are left with a solid containing W. This solid represents the First Brillouin Zone (FBZ). 

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