Modeling involves making a representation of something. Creating a tiny, functioning volcano is an example of modeling. Teachers use modeling when they have a class election that represents a larger one, like a presidential election.
Modeling is anything that represents something else, usually on a smaller scale. Military commanders use physical and computer modeling to plan offensives. Modeling is helpful because it allows you to take a good look at something that is too big or impractical to see otherwise. If a tall beautiful person tells you he has a modeling career, he’s not a miniature version of something, but he does make money being a model. Outside the US, it’s often spelled with two l’s.