title: How to make a div move up and down like a floating baloon
body: <p><strong>Overview</strong></p>
  
  <p>I want a div to be moved up and down, slowly, looking like a baloon floating in the air. </p>
  
  <p><strong>Findings</strong></p>
  
  <p>I came up with this and note the external script attached to it : <a href="http://jsfiddle.net/FLMp8/1/" rel="nofollow">link</a></p>
  
  <p><strong>Issue</strong></p>
  
  <p>One, it is not very smooth and it looks like breaking. Two, as you can see, the image looks like its being squashed when it moves up and down. How can I make it move smooth or is there another way to do it?</p>