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.
When Malfoy and his friends bother Ron and Hermione, Harry shows up and messes with the three boys. He grabs hold of Malfoy's feet, lifts them in the air and pulls him across the snow. In the first close-up of the soles of Malfoy's boots, not a speck of snow is on them, though he was just walking in it! Then in the next close-up, his feet still in the air, the soles are now covered in snow.
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.