Conflict indicates outright confrontation. Two people arguing. Two armies fighting. Or even something slightly less aggressive, such as someone who desperately needs money losing their winning lotto ticket. Tension, on the other hand, is what I like to think of as the threat of conflict. You’ll have tension in a scene in which your characters are hunkered down in a bunker waiting for the next artillery bombardment. You won’t have any actual conflict in this scene, since nothing is actually happening to the characters. But you do have plenty of tension because characters and readers alike know something is about to happen.
Think of conflict and tension as pistons, working in concert, pushing and pulling to provide contrast within the story. If you’ve got your conflict going gangbusters in every single scene, you’re going to find yourself in the ironic position of having created a monotonous story. Tension allows you to dial down the excitement and the altercations without losing reader attention. In fact, tension-heavy scenes can often be more gripping, simply because readers know the conflict is coming and they can’t do anything to stop it.
So bottom line: you need to strive to have either conflict or tension in every scene. But recognize the difference, so you can balance and enhance the effect of each.
K.M. Weiland