Suspense

Definitions of suspense:

Suspense is a way of creating drama, it foreshadows future events that will eventually have an impact on the audience. In terms of films, they include unanswered questions in the plot which the audience are desperate to know the answer to. In some cases the audience know more than the characters do on screen, creating tension. Alfred Hitchcock calls this 'The Bomb Theory'.The affect this has on the audience is Visceral, which affects bodies physically. Examples of this include sitting on the edge of the seat, screaming in terror and increasing the heart rate.
  
Another form of creating suspense is by showing it through 'False Plateau'. This means that the audience is being lead onto believing something that is not actually the real thrilling event but then the real event follows after. An example of this is included in the movie Jaws, when two boys were believed to be sharks but they were just swimming with cardboard fins. As this made suspense and scared the people in the water and the audience, the relaxation afterwards leads onto the real suspense when they find out there is actually a real shark in the water.

Picture from Alfred Hitchcock's 'The Birds':