查了下美国的project,
Project is bigger than regular homeworks. It requires more thinking and more research than the usual answering-the-questions homework.
Most of the time you have to work with others in a team, to come up with a specific topic which falls in the suggested fields the professor provides, then construct the structure of the project, and do research on the areas you have defined. After the research is done, you need to team up with your teammates to write up a report, or that sort of things. If the professor requires the team to do a presentation, you may want to prepare some handouts to students for easy understanding and practice your report with timing in mind.
It's basically not harder than the homework. It just requires much more work and deeper thinking.