Sound waves are vibrations that travel through the air, water, or solid materials. When an object, like a musical instrument, produces sound, it creates waves by causing the surrounding particles to move back and forth. These waves can be detected by our ears, allowing us to hear different sounds, such as music or speech. Sound waves are classified as longitudinal waves, meaning the particles of the medium move parallel to the direction of the wave. They can vary in frequency and amplitude, which determine the pitch and loudness of the sound we perceive. Higher frequencies produce higher pitches, while greater amplitudes result in louder sounds.