Does "on" mean on the surface of something?
I have seen a lot of people teaching "on" means "on top of", they are almost right, but before coming to insult me or freak out, I'll explain, On means Attach by one force; The key's on the table, When we say that sentence, what we really wanna say the key is attached to the table by gravity and not that the key is really on top of it, so that sentence can be translated for "A chave esta na mesa" in Portuguese.
Fine How can you prove me that?
The sentence: The graffiti is on the wall, can we say the graffiti is on top of the wall? No, We both know that's impossible 'because the graffiti is beside the wall, Another example is: He's on Mars means he's on the surface of Mars by gravity.
How can I something's on the surface of something? The question's very simple, you can say like so: the key's on top of the table. But using the preposition "on", everybody knows that the idea is, the object is on top of another, but when someone teaches other people like so, people can't get some sentences.
"on" means in contact with something by one force, and "on top of" means really on the surface of something.
Check it out in Portuguese at https://www.duolingo.com/comment/7028257