why is the chapter entitled the sound of the shell

In this chapter, for instance, Golding introduces the bespectacled Piggy as a representative of the scientific and intellectual aspects of civilization. Piggy thinks critically about the conch shell and determines a productive use for it—summoning the other boys to the beach. The conch shell itself is one of the most important symbols in the novel. The conch shell represents law, order, and political legitimacy, as it summons the boys from their scattered positions on the island and grants its holder the right to speak in front of the group.

Sorry- it's introduced in this chapter as a symbol of civilization- it's power lies in its "sound." Thus, the chapter's name.