11. The compression wave and therefore the air molecules move at exactly the speed of sound in the medium. 12. This system should not be confused, however, with the propagation of sound as compression waves in liquid. 13. A wide variety of compression waves are created, but only some ( primarily the odd harmonics ) are reinforced. 14. The only explanation for fast emission propagation is the dual of the active traveling wave, the active compression wave . 15. Active compression waves were proposed as early as 1980 by P . J . Wilson due to older experimental data. 16. P-wave refraction evaluates the compression wave generated by the seismic source located at a known distance from the array. 17. When the deflagration begins, a zone of significantly elevated pressure travels outward through both air masses as a compression wave . 18. :: Sound waves are compression waves , they move through the air by quickly compressing and decompressing the surrounding molecules. 19. These different waves ( compression waves and the different polarizations of shear waves ) may have different speeds at the same frequency. 20. A compression wave comes from tiny pieces of the medium conducting it along, smashing into the next piece, and so on.
