Crystals in Technology

Liquid crystals sit between solid and liquid. Their molecules flow like a liquid but stay neatly aligned like a crystal. An electric field shifts that alignment, controlling how much light passes through — which is exactly what a display needs to switch a pixel on or off.

Piezoelectric crystals turn pressure into electricity, and the reverse: apply a voltage and they vibrate. Beyond watches, this drives ultrasound scanners, sonar, and the igniter in a gas lighter that produces the spark.