Reeve's Cup magic

well....some of u may hav seen this trick before...haha its a simple trick which uses a simple science theory.... but mi practice a few times...if not will kena loophole:) so mi uploaded it on youtube...hmm...so the jest of it is hw come the red ball manages to pass through the metal cup every time??? well...there's nth special abt the cup though...the red ball oso nth special...and there's no special mechanism for the cup to open a hole for the ball to go through ya:)...btw the death-note notebook in the background is my bro's de...dun wry...wont write ur name inside de ya:) enjoy:)