How it reaches our ear:

1. The source: Imagine you strum a guitar string. The string vibrates back and forth, pushing and pulling on the air molecules nearby.

2. Compression and rarefaction: These vibrations create areas of compression (where the air molecules are closer together) and rarefaction (where they're further apart). Think of it like dominoes falling in a line, pushing each other forward.

3. Chain reaction: The compressed air molecules bump into their neighbors, pushing them closer together and creating a new compression area. This, in turn, pushes on the next set of molecules, and so on. The rarefaction zones travel similarly, with areas of lower density moving through the air.

4. The sound wave: This chain reaction of compressions and rarefactions forms a sound wave that travels outward from the source. The distance between each compression or rarefaction is called the wavelength, and the number of waves passing a point every second is the frequency. These two factors determine the pitch and loudness of the sound we hear.

5. Reaching your ears: When the sound wave reaches your ear, the compressions and rarefactions push and pull on your eardrum, causing it to vibrate. These vibrations are then transmitted to tiny bones in your middle ear and eventually to the hair cells in your inner ear, which convert them into electrical signals that your brain interprets as sound.

Difference on Air: