Sound is a type of energy that travels through the air (or other mediums) as waves. These waves are created by vibrating objects, which cause the surrounding air molecules to move and create pressure variations. Humans perceive these variations through their ears, allowing us to experience music, speech, and environmental noises. The study of sound encompasses various fields, including physics, music, and psychology. Sound waves can be classified into different types, such as ultrasound and infrasound, based on their frequency. Understanding sound is essential for numerous applications, from audio engineering to medical imaging.