When Room 7 and Room 9 visited Armagh Planetarium we designed and built our own rockets. We used plastic bottles, masking tape, a weight and card to design and make the rockets.  Once we had constructed our rockets we brought them outside where they were half filled with water before being put on the launcher.  Once there, they were filled with compressed air and we had loads of fun watching them launch high into the air.  After watching how far some of the rockets reached we realised that that the cone at the top of the rockets and the fins along the side were important in order for it to be more aerodynamic.