No one talks. Everyone stares at the display that indicates the current floor. It occurs in a variety situations - on buses, in doctor's waiting rooms, in laundromats, at the check out line of the grocery store, etc. The elevator effect is very important to you as a teacher. A classroom is a giant elevator, and you are its attendant.
Students board the elevator at the beginning of class, walking into a room full of strangers.
The door to the room shuts. They sit through a 50 minute ride, staring at you, or the board, or the ceiling the entire time. At the end of 50 minutes, the door opens and the students get off the elevator. Viewing the classroom as a giant elevator explains a number of rather curious things about student behavior in the classroom. This behavior is controlled by the elevator effect.