Where can I get info on the Amendments?

So I have to write a mid term paper for my government class and I have to write about an amendment. So my question is there a site that I can go one to get the history and background on an amendment? I'm writing on the 4th amendment and I already have the information on what it is and how its used and blah blah but I can't find background history on it like why it was created and everything like that I mean I think I already found why it was created but I was just curious if anyone knew of any site about it because I just want to be SURE! If it was in my government book this would be real easy but my government book have no info on the amendments.