Cannot Enqueue Scripts?

Hi all,

I’m attempting to load a javascript file (eventually will be multiple js and css) into the header of the site. As far as I can tell, it should be a simple process of defining a custom function in functions.php and using add_action() to register it?

Here is my code (in functions.php):

function load_scripts_and_styles() {
	$root = get_theme_root_uri();
	$dir = $root . 'evos/js/functions/functions.js';

	wp_enqueue_script('functions', $dir);
}
add_action( 'wp_enqueue_scripts' , 'load_scripts_and_styles' );

I cannot understand why this isn’t working, I would of thought it would be simple or at the least I would get some kind of error?

Thanks in advance