Var & Vart

Var and vart is used in questions. It means where, but in different ways.
Say you wanted to know where you and your friends were going (a location).

Vart ska vi gå nu?
Where shall we go now?
In this case you should use "vart" because theres' activity involved in the question. You're asking about where you're going; wherever it is, you're *going* to get there.

"Var" is used in questions that asks where a certain thing is located:

Var är min strumpa?
Where is my sock?
Therefore, "Var" is used in questions about something static, not moving from its place.

Most swedes are lazy with these two words, they only use "Vart" in both cases which is wrong. I don't know what's up with them people :)