FUN SCIENCE EXPERIMENT! In chap. 3 of the book Farmer Boy it says: "You can fill a glass full to the brim with milk, and fill another glass of the same size brim full of popcorn, and then you can put all the popcorn kernel by kernel in to the milk, and the milk will not run over. You cannot do this with bread. Popcorn and milk are the only two things that will go into the same place."