is the charge that accumulates in solid materials in response to applied mechanical stress. Substances that exhibit piezoelectric properties to a greater or lesser extent are crystals (Tourmaline, Quartz, Topaz, Rochelle salt and sugar cane), certain ceramics and biological matter such as bone, DNA and various proteins. Quartz and Rochelle salt exhibit the greatest amount of piezoelectrical properties and since the ingredients and instructions for making Rochelle salt are relatively straightforward I decided to make some to play with. I found some helpful guides here
, but diverged from both guides several times without ill effect. Here are my instructions for making Rochelle salt (Potassium Sodium Tartrate), which yielded at least 5 tablespoons full of the salt and several large single crystals in a few days.
I've recorded two mechanical force tests of a single crystal using both a digital and analog oscilloscope here