Sirius Black: Brilliant, Snape. Once again you've put your keen and penetrating mind to the task and as usual come to the wrong conclusion.
At Hagrid's, when Harry, Ron and Hermione are there the first time in the film, there is a large birdcage, blue cup and saucer, watering can and small wood planter (with seedlings) on the windowsill. Later, when Hermione visibly throws the first stone, as the stone flies through the window the watering can and blue cup's positions differ and the wood planter and large birdcage are actually gone! When she throws the second stone they are back on the windowsill.
In order to acquaint himself with his three lead actors, director Alfonso Cuaron had each of them write an essay about their characters, from a first-person point of view. Emma Watson, in true Hermione fashion, went a little overboard and wrote an 16-page essay, Daniel Radcliffe wrote a simple one page paper, and Rupert Grint never even turned his in, as he said that is what Ron would have done.