Summary: You see a movie at a movie theater; you watch a movie at home.
When I first started teaching English some twenty-five years ago, a constant area to cover in a lesson at some point was the difference between seeing and watching, for example, seeing a movie and watching a movie. Most of the English books that we teachers used in our classes had at least one unit devoted to covering the topic. Other books also explained the related difference between hearing something and listening to something. In classes, we generally described the difference simply like this: You see a movie in a theater, and you watch a movie at home. Or to put it differently, you saw a movie on a large screen and watched a movie at home on a small television set (for example, with a VCR (a very old device used to play videotapes)). Remember, this was at a time when only the wealthy owned large-screen TVs and DVDs did not even exist, so the distinction between the two types of screen was quite a marked one and was therefore all the easier to explain.
The grammar rule: see vs watch
For those students who were more curious and had more questions, I would typically explain that seeing a movie had something to do with the larger screen typically found only in cinemas, which created a more immersive experience. Watching seemed to be a more deliberate, active activity – one had to make a conscious effort to watch something, whereas seeing something was slightly more passive, as if it were occurring before your eyes and you happened to see it. My students seemed to accept this explanation unquestioningly, even if the distinction seemed an unnecessary one.
I never noticed native speakers of English making this mistake, and it was taken as a given that this distinction was an important one, though one that wasn’t completely necessary for the most basic level of communication. So imagine my surprise when I started to notice, some twenty years later, native speakers making this error. In fact, at least among the group that I teach – high school students in San Francisco – the dominant usage is to watch a movie; rarely do I hear students saying that they are going to see a movie.
Complicating things is the fact that home screens are getting larger, and many of the smaller independent cinemas, at least in San Francisco, seem to be quite small in comparison with the stadium-seating in the giant multiplex cinemas, so it could be argued that the home experience, especially if you throw into the mix a $5000 home theater system, is just as immersive, if not more so, as the one in some movie theaters.
It is also completely possible that the language is changing, and the distinction between watching and seeing is disappearing; it certainly seems that way among many of the people I know and interact with. However, if you’re a traditionalist, a purist, or dare I say even a prescriptivist, we see a movie at the theater and watch a movie at home.
On a related point – we typically also see (not watch) other related visual arts– we see plays, we see performances, and we see recitals.
Finally, in a few days I should be able to upload a see vs watch grammar worksheet in our new Worksheets section, if you’d like to test yourself or your students.