$(document).ready(function(){
 
  
  var bouncespeed = 800;
  
  $('#bubble li').each(
    function () {
      $(this).css({top: '0px', left: '0px'});
     bounce(this);
   }
 );
  
  function bounce(circles) {
    newx = Math.floor(10*Math.random());
    newy = Math.floor(10*Math.random());
    newspeed = bouncespeed + Math.floor(0*Math.random());
   $(circles).animate({top: newx + 'px ', left: newy + 'px'}, newspeed, 'linear', function() { bounce(circles);});
  }

  
});