In terms of chronological status, it has been months since I have posted here, and I am now an eleventh grader (with another Physics-based interest). As of now, there are multiple technologies in existence that could possibly be used to run vehicles in the near future: hybrid systems, bio-fuels (ethanol), fully-electric cars (such as the Tesla), hydrogen fuel cells, etc. What I have been pondering about is whether or not it is possible to run a mechanical engine on controlled explosions caused by the reaction between Hydrogen and Oxygen (creating H20 as a result; electrolysis separates the H2O into usable fuel). This uses both Chemistry and Mechanical Engineering, so I don't know if I posted this in the correct forum; sorry if this question needs to be moved. Do you think this water-engine is possible? Give your opinion(of course, with some reasoning).