Sorry, but some of you may think this is a stupid question. (I'm only 16 years old.) I have just now gotten into the field of tensors and topology, after studying vector calculus and differential equations and I have two questions: a) What exactly is a covector? b) What is the difference between a contravariant and covariant tensor, and any mixture of the two, in a geometrical sense? (I already know the transformation equations but I find it hard to deduce a relative view of these.) Any help will be especially appreciated as I cannot find any source that will explain this to me. Thank you.