Presidents - A cherry tree

I am doing a unit on Presidents with my 2nd grade class.  They have little to no knowledge about who a president is, so we are learning- slowly but surely. :) I started out the unit by watching a short 10 minute video about Abraham Lincoln & George Washington.  They learned the fictional story about George Washington and the cherry tree.  We then made our own tree with our hands.  There are 44 hand prints (one for each president) and the students wrote the presidents' names next to each leaf.  We may not fully grasped who a president is, but we do know there have been 44!