how to build a water rocket out of a 2 liter bottle

...the western city of Osaka on Thursday, saying that a liter (2.1 pints) of any kind of...to run as long as you have a bottle of water to top up from time to time," ... TV Tokyo. "It does not require you to build up an infrastructure to recharge your ...? There's no rocket science here: you can't get more energy out than you put in... educate people about very simple scientific ideas. How can we do better?...