The document discusses different types of sound used in moving images including diegetic and non-diegetic sound. Diegetic sound is anything that characters in a scene could hear, including recorded sounds and additional Foley sounds added later. Non-diegetic sound consists mainly of music that characters cannot hear. The document analyzes sounds in film clips to understand how specific diegetic sounds like a blender, ball bouncing, and birds signing are used deliberately to heighten tension and signify meanings like an impending disaster.