Is There a Difference Between Schemata and Mental Model?

The terms schemata, or schemes, and mental model are often confused. Can you describe the difference between the two? They do have a lot in common, so i can understand how they would be confused. A mental model is the expectation that some one has about a product or an experience. It's what do i expect when i'm going to read a book? I'm going to go to the movies. What does a training course mean to me? Younow.