Piezoelectric (pronounced like “pee-ay-zoh-electric”) describes materials that create electricity when you squeeze, press, or vibrate them. It also works the other way: when you run electricity through these materials, they change shape slightly.

Think of it like this: certain crystals and ceramics have a hidden power. Press on a piezoelectric crystal, and tiny electric charges appear on its surface. Send electricity into that same crystal, and it squeezes or expands just a little bit. This two-way trick makes piezoelectric materials incredibly useful.

You've probably used piezoelectric technology without realizing it. Those long lighters that spark without needing a flint? They use a piezoelectric crystal. When you press the button, it squeezes the crystal, which instantly generates enough voltage to create a spark. Some electric guitars use piezoelectric pickups that turn the vibrations of the strings into electrical signals. Ultrasound machines that let doctors see inside the human body rely on piezoelectric crystals that vibrate millions of times per second.

Scientists discovered this property in the 1880s when they noticed that certain crystals generated electric charges under mechanical stress. Today, piezoelectric materials power everything from quartz watches to sensors that help detect earthquakes.