Science Wish List Photogates and Timer Stands ($150-$500) Marble Launcher (CPO 6 sets for $795) http://www.freyscientific.com/SupplementalCurriculum/CPOScience/CurriculumResourceGuidesandEquipmentKits /Marbl eLauncher/tabid/252/Default.aspx Duct Tape - Lots and lots of duct tape!