Before I started listening to the Writing Excuses podcast I had never heard the terms "scene" or "act" in reference to prose. Plays or musicals are broken down into acts and scenes very definitively and movies have scenes, but prose is generally left at chapters. The truth of the matter is that prose has scenes and acts as well, they're just a little less straightforward.
Scenes come in many flavors. Genre plays a huge role in the length, purpose, and structure of each scene. In thriller novels, scenes are typically very short, each placing a tiny piece into the "plot puzzle". More involved works have longer scenes that either move the plot forward, develop characters, or reveal the setting. Calculated manuscripts may contain "sequels" to scenes, a cooling down period that helps to develop narrative rhythm. Most scenes come from a single viewpoint, although examples, such as Dune, exist in which multiple characters have viewpoints within the same scene. Scenes are separated with either a line break or the ending of a chapter. Epic fantasy chapters often have multiple scenes, whereas lighter reads usually use chapters as scenes.
The most common narrative outline using acts is the Three-Act Format. I saw a horror movie shortly after discovering the Three-Act Format. The fact that it was a movie played a part, of course, yet it was funny to find how clearly the acts began and ended. I could predict events that would happen based upon the Format as well. Unfortunately, the movie was somewhat boring after being dissected...First Acts are what you would call "rising action" in school. The Second Act has more escalation, sometimes character failure at the brink of success, and occasionally the climax at the end. "Falling action" makes up most of the Third Act (assuming there is "falling action"), with the climax toward the beginning if it didn't happen already.
Hopefully nobody's mind has been blown too hard. Scenes and acts in prose? The concept is a tad strange, but it makes sense and the notion can really help you with your writing, especially if you are an outliner.