1. A source of vibration: This could be anything that moves back and forth, such as a plucked guitar string, a vibrating vocal cord, or a speaker cone. The vibration creates disturbances in the surrounding air.

2. A medium for the wave to travel through: Sound waves are mechanical waves, which means they need a physical medium to propagate. Typically, this is air, but sound can also travel through liquids and solids.

3. A receiver to detect the vibrations: This could be our ears, which convert the sound waves into electrical signals that are interpreted by the brain as sound, or a microphone, which converts the sound waves into an electrical signal that can be amplified and recorded.