This is how to make a catapult using a ziploc bag. All you need is a recloseable bag and ammo that is the size of a marble or something. It can be anything, mushed up sandwich balls, penuts, meatballs. First blow up the bag all the way and then close it. Then let a little bit of air out of it and close it again. After a while you will know how much to take out. Then take your finger and push one of the corners into the bag. Now take the ammo and stick it in the corner you pushed in. Aim it so the corner inside the bag is facing away from you. With both hands push really fast but not hard and the corner will go out and the ammo will fly across the room. I do this in lunch and its funny watching a meatball careem into someone's table and knock everything over or watching kids reactions when they get smacked in the face. Don't let the teachers know how your doing it though or they are going to stand next to your table watching you like a hawk.
