CBSE Class 9 Answered

Sound is produced by vibrating objects. Particles of the medium in contact with the vibrating object first displaced from its equilibrium position and then bump into its neighborough.  Solids are denser because the distances between molecules in them are very small. Hence, molecules take comparatively less time to run over its neighboring molecules. When Sound propagates through the solid, disturbance created by sound moves through a medium and immediately transferred the motion to its next nearest particle and set them into motion. They turn into similar motion with other particles. Particles do not change their place but their motion is carried forward.

 Transverse wave in which particles oscillates up and down about their mean position. Energy transfers through the individual particles of the medium moves about their mean position in the direction perpendicular to the direction of wave propagation.