Hi, I have never swung before, but I have a question for this group!

I was wanting to re-create the david vs goliath scene for a kids play and thought i could teach my 12 yr old how to swing in order to really captivate the crown. Would any of you think it possible (and safe) to re-create this using a ping pong ball or some other safe soft object at 20-25 ft?  any advice is welcome!

You can roll a sock up into a ball.  If you have a gray sock, it will also look like a big stone. 

The easiest and safest (this is a weapon) way would b to put a whip cracker on the sling and use no projectile. The crack of the cracker will b loud enough to get the reaction from the audience u r look for. And then the kid playing Goliath could have a prop foam stone that has sticky on it that he could smack to his forehead right after the crack of the sling and play dead. A lot easier and faster to learn to get the sling to crack good and u don’t have to worry about an errant shot hitting something or someone not intended too and making problems. This is a weapon, not a toy! I was always taught, you DoNot point a weapon at anything you are not will to destroy.