Hmmm, this experiment got the University of Sonno Bet thinking so they tried the experiment again by using another formula: Vf^2=Vi^2+2ad Data was collected by launching a small rocket and was filmed. Data collected ended up being: Vf=16.1m/s Vi=47.9m/s delta d=103m And by pluging all these values in they ended up with acceleration due to gravity as -9.87m/s^2 With an uncertainty value of 3.3%. Sources of errors include, air resistance and terminal velocity as the experiment was conducted within the atmosphere. It would be interesting to see more experiments conducted like these. Edit: OOC: Anyone know if these are up to date? http://kerbalspaceprogram.com/~kerbalsp/wiki/index.php?title=Kerbin