Here's why:
* Vibrations create waves: When something vibrates, it disturbs the surrounding medium (like air). This disturbance travels outward as a wave.
* Compressions and rarefactions: Sound waves, like those created by vibration, are longitudinal waves. This means the particles of the medium (air) move back and forth in the same direction as the wave travels.
* Compressions are areas where the particles are pushed closer together, increasing density and pressure.
* Rarefactions are areas where the particles are spread further apart, decreasing density and pressure.
So, the compressions are the regions of higher density and pressure created by the vibrating object pushing the air particles closer together.
