Abstract:
Tourmaline is the crystalline form of the mineral aluminum borosilicate with 3m symmetry. Because tourmaline is a uniaxial polar crystal, it develops a spontaneous charge during a temperature change (pyroelectricity). Since the polar symmetry direction coincides with the long axis of tourmaline crystals, the two ends develop opposite charges. Consequently, a heated crystal suspended by a strand of thread is either attracted or repelled by a second heated crystal, due to the charges on the respective crystals. In this work, the crystals were heated by light sources of differing frequencies including; 650nm (red), 570nm (yellow), 510nm (green), and 475nm (blue) to create various charges. A device was created that demonstrates this effect. This device can be used to show the effects of pyroelectricity in a lab or classroom setting. Effects of the charged crystals were observed. Findings are presented in this work, along with the effects of humidity and ambient conditions on tourmaline's pyroelectric properties.
