على = ملامس لما تحته ، وضعت القبعة على راسي فوق = غير ملامس ، افلم ينظروا الى السماء فوقهم؟

on = على above = فوق

Prepositions in Arabic called in a lot of old Arabic grammar books (Prepositions of meaning), so you can know the meaning of them and you will be able to use them according to the meaning: على on في in إلى to عن about فوق above and so on

on = على above = فوق we can use the word على for thing on table, as example: I'm sitting on chair = انا اجلس على الكرسي we cant use the word فوق instead of على for the phrase context for word فوق we use it to say that thing above another one they could be not in touch, for example : the lamp above me = المصباح فوقي i hope that is helpful.

*الاستخدام