Play is a child's language, not words! They NEED play to understand how the world works! Let them get wet, play in the mud, make noise, run & jump!
When you lecture a child you bury them in a mountain of words they rarely understand. Keep you requests, reprimands, requirements, and rewards short & simple ("Please don't throw the ball in the house."). Don't follow that with sentence after sentence explaining why they shouldn't, or what could happen, or what will happen if they do it again. By the time you're done with that rant the kid often wonders what your original request was.
And if it's not going to hurt anything in that room, let them throw the ball!
Mary Bowles, MA, LMFT, RRT, MIAAN