I dont think a minecraft forum is the greatest place in the world to be seeking science fair project ideas
		
		
	 
 I dunno.  I think it's a good starting point. Like, how about redstone circuitry?  You can create a circuit in game that lights up different redstone lamps depending on which combination of switches are used.  That would translate into a rl circuit where you can use multiple switches to power different lights.
All depends on the grade level, tho. 

  might be good for 4th grade, but not 9th. XD