Related: Any parents out there, a fantastic way to show kids not to put their fingers in doors is to put a carrot in there, close the door so it breaks, and (at

Related: Any parents out there, a fantastic way to show kids not to put their fingers in doors is to put a carrot in there, close the door so it breaks, and (at the right emotional level for your kid) show shock and horror that this happened. The demo seems to convey it better than telling/informing them of this danger.