wp_enqueue_script and header.php

Hello, in my header file I am trying to include jQuery UI Dialog and I am using wp_enqueue_script to do like so:

wp_enqueue_script('jquery');
	wp_enqueue_script('jquery-ui-core');
	wp_enqueue_script('jquery-ui-dialog');
	wp_enqueue_script('swfupload'); //for testing enqueue fn
	wp_head();

However, this puts out only jquery.js and swfupload.js. I have tried enqueueing just jquery ui dialog with a path to the script and an array of dependencies for jquery ui dialog (as according to jquery UI’s development bundle which lists dependencies.) That still only printed out jquery.js.

I tried

wp_enqueue_script('jquery-ui-dialog');

by itself and it still just put out jquery.js.

Am I missing something?