Nel vs Sul
I understood that "nel" translated to "in" and "sul" translated to "on".
Now, two different translation questions in the Food category: (1) "La salsiccia e nel piatto" I answered "The sausage is IN the plate". Duolingo suggested another translation of "The sausage is ON the plate".
(2) "L'insalata e nel menu" I answered "The salad is ON the menu". Duolingo suggested another translation of "The salad is IN the menu".
To me, in both cases the translation should be "ON" the thing. In English, it doesn't really make sense that a salad is IN the menu (or that the sausage is IN the plate for that matter!!).
Could someone please clarify the uses of "nel" and "sul" in these instances?
What you're doing is very dangerous :P Prepositions aren't directly translatable even between related languages like French and Italian; you're better off learning the cases of use, or which preposition goes with which words. In the specific cases you mentioned, plates are considered containers in Italian, so food goes inside the cavity; you can say "su" if you put things outside the cavity or the plate is flat, e.g. a tray. A menu instead is both a list (so dishes are inside it) and a piece of paper, so depending on context "su" would be fine too.