"Where is Canada?"
The main difference between the both is the focus of the sentence. If you're wanna find out the location of the object, you use где and then the object. However, when the focus is more on an object than its location (e. g. your friends are late and you're calling them impatiently), then you will put the object before где. At least that's what I figure, the same thing is with Polish. I guess it's a matter of looser syntax - it lets you change the meaning and focus of the sentence with just switching the order of the words.