Piezoelectricity is a phenomenon where certain materials generate an electric charge in response to applied mechanical stress. This effect occurs in materials like quartz and certain ceramics, which can convert mechanical energy into electrical energy and vice versa. When these materials are squeezed, twisted, or otherwise deformed, they produce a voltage. This property is widely used in various applications, such as in microphones, speakers, and sensors. For example, in a microphone, sound waves create vibrations that compress the piezoelectric material, generating an electrical signal that corresponds to the sound.