R.J.
She's experimenting with gravity & physics. (Will it hit the wall with my eyes shut? When I use my left hand? With one eye shut? If I scream at the same time? Will is ALWAYS slide down the wall? Will THIS roll as well? Why not? Try again! Can I eat through my EAR??? Wonder of wonders... what about my HAIR???)
She's more interested in cause & effect right now than food. Probably because she's just finished a growth spurt. (During growth spurts kids eat like they're bottomless pits, but right after them, they can frequently live on less than what a bird would).
I really loved this stage (this is also the stage where you find things in weird places... like anything rectangular in anything else rectangular; like the sandwich in the VCR, or the box of kleenex in or under the bed OR when you find things in other relationships... like every single sock in reach piled on the shoes, or whole rolls of toilet paper dumped in the toilet bowl)... but I realize most parents don't.
To combat it
1) NEVER clean up after her (my son cleaned up each and every mess he made starting at about a yearish... of course with my help, but he didn't stop until the mess was cleaned up).
2) Give her a warning: If you throw it, you must not be hungry. She throws it, and down she goes. When she really gets hungry, she won't throw it. (Kids really don't starve themselves).