Although they are cool, unfortunately, growing crystals, making a replica of a volcano, etc. is not what schools are looking for in science projects these days. I just judged the science fair at my kids school. The best projects involved doing an actual experiment. You can find experiment ideas online, but here is one example I can give you that was really good: Have your son research different types of bridges to get an idea of what is already known about the strength of them (be sure to note this in the report). Then have your son make a hypothesis about what type bridge he thinks will be the strongest and why. Then have him do an experiment where he builds 2 different types of bridges out of craft sticks and glue. Then add weight to each bridge in increments (always use metric measurements in the report) to see which one can withstand the most weight before collapsing. Be sure your son states whether his original hypothesis was valid (true) or invalid (untrue). Your son's school should provide detailed, written instructions of what they expect for the project. Be sure to read them and follow them carefully. Leave plenty of time to do any project. Good luck.