Piezoelectricity (pee-EH-zoh-EL-ek-TRIS-ih-TEE) comes from the Greek word "piezo," which means "squeeze." Piezoelectric materials generate electricity when squeezed, and they expand or twist when electrified. Many substances can be piezoelectric, if they've got the right shape. Salt, sugar, quartz, and other common substances can form piezo crystals. The material is relatively unimportant; what matters is the crystal structure.
Piezoelectric crystals act the way they do because of asymmetry. A piezoelectric crystal is off-balance--it has more atoms on one side than the other. When the crystal is squeezed, the imbalance increases, creating an electric charge. If you connect both sides of the crystal in a circuit, you can generate an electric current. he piezoelectric nature of quartz is used in digital clocks and watches, as well as gas stove lighters. Some kinds of inkjet printers use piezoelectric crystals to squeeze ink out of tiny tubes. Many cheap buzzers and musical gadgets use piezo speakers to make sound.Scientists use piezoelectricity to explore and transform the nanoscale world.