How to make one div of many to slide down?

How to make one div of many to slide down?

Hi,
I am looking at this example: http://docs.jquery.com/Effects/slideDown#speedcallback

That makes all DIVs to slide down on the page, but what to do if I just want to make one DIV of several to slide down?

I have tried this but it didn´t work:
<script>
  $(document).ready(function(){
   
    $(document.body).click(function () {
      if ($("div:first").is(":hidden")) {
        $("contact").slideDown("slow");
      } else {
        $("contact").hide();
      }
    });

  });
  </script>
<div id="contact">dddd</div>