How Can I Explain Sin to an Elementary-Aged Child?

https://www.godtube.com/resource/mediaplayer/wzdpypnx.mp4;https://content.swncdn.com/godtube/2015/03/13/491858/491858_480p_posters13.jpg;https://www.godtube.com/watch/?v=WZDPYPNX;