Number of displayed posts

by

The WordPress function get_posts() supports:

'posts_per_page'  => 10,
'numberposts'     => 10,

so you should use:

$projects = get_posts(array('post_type' => 'projects', 'numberposts' => 10));

instead of 

$projects = get_posts(array('post_type' => 'projects', 'number posts' => 10));

If you want to show all posts, you can use 

'posts_per_page'  => -1

You can read more about this in the WordPress Codex:

http://codex.wordpress.org/Template_Tags/get_posts