I assume you are pretty much done with the school year and have some time to research this over the summer. A couple of good books to read, which may well be in your local library, would be The Age of Spiritual Machines
or The Singularity Is Near: When Humans Transcend Biology
, both by Ray Kurzweil. There is some degree of goofiness to that particular notion of singularity. It is not the least bit clear how a human mind could be hosted in a machine, for example, nor what it would be like. How would people who are still in their natural bodies interact with these "transhuman" beings? Such a thing is well into the foggy future. A more interesting approach: http://www.physorg.com/news/2011-06-dr- ... gence.html
If you hope to eventually get a science fair project out of it, you'll have to figure out some kind of super-simplified model system. If you know how to program computers, you might think of turning the problem on its head and write a chatbot with different degrees of sophistication in its ability to chat with users. Users could score how "human" the chatting is, and you would get an idea of what a "transhuman" might have to be like to a real human in order to still be considered human. Google the terms "chatbot" and "chatterbot", possibly along with "open source" to find programs and techniques to do this. If you can set things up in a way that you could switch on or off some important parts of the chatbot and have people score them, then you could do a student's t-test of the results and see what features give more human-like scores.
You'll need to think about this for a while, and read up on it. It's an interesting problem.