Sound is effective in horror films for several reasons. Silence can raise suspense and tension, while a soundtrack can accompany and escalate action sequences. A lesson activity had students watch a trailer for "The Shining" without sound to guess missing audio, such as an immediate soundtrack, voiceover, dialogue, and a child's scream. They also learned about diegetic sounds, which characters can see and acknowledge, and non-diegetic sounds that only the audience can hear, like a soundtrack or voiceover. When watching with sound, some of the student's guesses about missing effects were correct, but the music played throughout the entire trailer.