I read somewhere that throwing things (including food) on the floor is a totally normal developmental stage. They apparently like to see what happens when something is in their hand and then not. I'm not explaining it very well and can't even remember where the heck I read it, so I'm probably not being very helpful.

But what I am trying to say is that it's normal and even healthy to do that - but annoying for you having to clean it up all the time!!
Sue x