Why does the teacher do this?

There is a teacher in my school, who looks at me quite frequently. He isn't a pervert that i know of , and he seems a very nice guy. Hes married, and is quite a good teacher from what iv heard, but i'v never been taught by him. Well anyway, i catch him looking at me, not like my body or anything , like hes fascinated as though hes trying to find out more. I'm don't look like a lot of girls in my school, i'm more exotic looking, but i'm really curious. I was standing outside and he was looking at me through the window whilst talking to another teacher, and in the corridor he was standing there and he glanced at me a few times. I really don't think he fancies me, i'm not the type who has school girl crushes either. If ever i see him he looks as if curious. btw i dont fancy him or anything so nice answers please