site 1 -> http://www.ajc.pt/cienciaj/n12/gta.php3 [Simples] site 2 -> http://orbita.starmedia.com/~paladinohp/principal.html [Site azul] site 3 ->http://homepage.ntlworld.com/telescope/Rocketweb/Launcher.htm [Ingles] Site 4 http://www.clubequark.org.br/experiencias/foguetes_de_agua.htm