I have figured out a way to make a rocket fly get some soda and mix it up with water and put it into 4 straws divided in to 16 equal bits.Then get a plactic water bottle and fill it with vinegar (half a bottle). After put the 16 rods in it and quickly screw a fairy liquid bottle on top and give it a shake . Get 2 polls and stick them either side of a large strip of string ,get some card bourd and attach it to the rocket and string.