Sound: Frequency, Velocity, and Intensity Sound is a mechanical wave that propagates through a medium (such as air, water, or solids) due to the vibration of particles. The properties of sound—frequency, velocity, and intensity—are key to understanding how sound behaves and is perceived by humans and other organisms. 1. Frequency of Sound 2. Velocity of Sound 3. Intensity of Sound 4. Relationship Between Frequency, Velocity, and Intensity 5. Applications of