Another easy way to make the top of a waterfall like he did here with the powerade is to go buy one of those metal pipes that look really gay and make sure the bowl screws in to the shaft of the pipe where you can unscrew it off.

Like the one on the top of this picture: Image:Metal-pipes.jpg - Wikipedia, the free encyclopedia

then drill a hole in the top of a bottle cap so that it is the same size as the screw-in bottom section of the bowl from the pipe WITHOUT the threads of the screws, doing this allows you to securely screw in the bowl to the bottle cap. If you're like me, you like smoking out of all different things, so i just keep this cap n bowl around with all my other smoking stuff, if ever i get the desire to make a gravity bong, lung, waterfall etc. i just whip it out and i already have the hardest part done