[jQuery] hover with unordered list

[jQuery] hover with unordered list

I'm tryin to do a hover effect for a using a unordered list....this is what my code looks like:
<script>
$("#categories > li").hover(function(){
     alert("the mouse is over");   
},function(){
        alert("the mouse is out");   
});
</script>
<div id="categories">
<ul>
<li>Category 1</li>
<li>Category 2</li>
<li>Category 3</li>
<li>Category 4</li>
<li>Category 5</li> 
</ul>
</div>
i've tried different variations for selecting the element including $("#categories > ul > li"), but nothing is happening. I'm sure i'm overlooking something....