In 1880, two brothers found that squeezing a crystal can generate electricity
Pierre and Jacques Curie, working as young lab assistants in Paris, discovered that pressing certain crystals like quartz and tourmaline produces a measurable electric charge on their surfaces. They built their own instruments from tinfoil, glue and wire to prove it, and also found the reverse effect: an electric field could deform the crystal. Piezoelectricity now powers quartz watches, ultrasound machines and lighters.