rocket first launch off

Yesterday me and the rest of SWL went out to the field and had our first launch off with our rockets and our administrator Lincoln helped us out.
To launch it we had to have a bike pump 1.5l fizzy bottle safety glasses a launch pad wich for us was the field pressure gage measure jug and water. first we had to set up the launcher that is the bike pump if you didn't know then we had to measure the water into the bottle after we filled the water up to the measure then we connected the bottle to the bike pump.
then we used the pump and made sure nothing was wrong with it.Last but not least blast off our first try didn't launch until 10 seconds after Lincoln pushed it.