What Car Award 2010 and 2011

[Ninx]

I am usually too scared to post here but this has got my goat good and proper.

Please explain the difference between what and which to me. It must have been done a million times but hopefully there will be newbie pedants who can help

OK, this got me thinking. It also got me googling, I have to confess. In short, Which suggests there is a response chosen from a restricted set, for example Which Car could imply 'which of these xxx cars' and that the person asking the question has knowledge of what the set is; whereas What refers to an open set, ie the person asking does not have any clue as to the possible answer.

Another way of putting it:
What car would you choose?
Which family car would you choose? Or which car will you take today?

Thanks for getting me thinking!

Oh thanks for that NumptyMum!