Exposition through dialogue is usually a necessary evil in screenplays. Make no mistake, it is an evil. Exposition refers to communicating the facts an audience needs to accurately comprehend your storyline. Exposition can be visual. or it can be handled through dialogue. The golden rule of exposition through dialogue is this: avoid it at all costs. As with most things in screenwriting: show, don’t tell. Imagine the following scenario: two children are stuck on a seesaw with a bomb strapped to it. A tilt sensor has been built into the device if the seesaw tilts too far either way. An FBI agent is trying to coach the children and their parents to safety. Let’s take a look at exposition through dialogue: hey kids, nobody move, I’ve seen this kind of device before! It has a K29 variable mercury center attached to it, tilt the bomb too much and it’ll go off, so everybody stay very, very still until we figure out how to disarm it. Long, drawn out, and insulting an audience who feels they are being unnecessarily spoon-fed the facts. Now let’s look at an alternative visual exposition: hey kid, slowly lower yourself down. Stop! Back up! Same concept is communicated but with elevated suspense and zero boredom.