Piezoelectric Flash Rocks
Two Quartz rocks which have piezoelectric properties. Hit them together and generate light and sparks. Piezoelectricity is the ability of certain crystals to produce a voltage when subjected to mechanical stress. The word is derived from the Greek piezein, which means to squeeze or press. The effect is reversible; piezoelectric crystals, subject to an externally applied voltage, can change shape by a small amount. The effect is of the order of nanometres, but nevertheless finds useful applications - for example fine focusing of optical assemblies, etc.
- 2 quartz rocks with piezoelectric properties
- Spark and glow in the dark when rubbed against each other
- Do not hit these rocks together - just rub
- Best observed in a darkened room
- A product of the USA
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