How to sell nonsense in your screenplay (the Klein-Hasslepark Effect)

Recently I saw “Source Code,” a movie I enjoyed even though ultimately the explanation for what is happening is nonsense. (I know some of you will disagree, but I can't get into it without spoilers and the point below is valid even if this one isn't nonsense, because plenty of movies are.)

The key to movies like this is keeping things moving so the audience doesn't have time to think about it until afterward, and keeping the explanations short.

“Source Code” has a repetitive aspect but each iteration moves quickly and introduces another element to keep our interest, and the keeps things moving along at a good clip. It's like hucksters at the county fair or time-share salespeople who talk so fast that your brain can't keep up and just gives up.

However, don't give your mad scientist too much exposition because in all probability it will be boring and the audience will switch off and that gives them dangerous time to consider whether anything is making sense. You don't want them to do it. Better to say something like, “This is the first time the Klein-Hasslepark Effect has affected anything larger than a proton! That's why your wife no longer has human form!”

And then hope for actors and a director as good as the folks behind “Source Code.”