Sound is produced when something vibrates. The vibrating body causes the medium (water, air, etc.) … Vibrations in air are called traveling longitudinal waves, which we can hear. Sound waves consist of areas of high and low pressure called compressions and rarefactions, respectively.
Sound vibrations travel in a wave pattern, and we call these vibrations sound waves. Sound waves move by vibrating objects and these objects vibrate other surrounding objects, carrying the sound along. Sound can move through the air, water, or solids.
Read through the notes which explain these concepts. Applications to real life situations are also included. To consolidate knowledge watch the crash course revision video on the link provided.