Vibrations are rapid movements back and forth or up and down. They occur in various objects, such as strings on a guitar or the surface of a drum. When these objects vibrate, they create sound waves that travel through the air, allowing us to hear music or other sounds. Vibrations can also be found in everyday life, like when a phone vibrates to alert you. They are measured in frequency, which is the number of vibrations per second, usually expressed in hertz (Hz). Understanding vibrations helps in fields like engineering, music, and medicine.