Being a science fair project, I am sure the teacher is not expecting much, but that's no reason not to go the extra mile.
I always wanted to make a gyroscope atom as a project, but never was required to make a science project, so my dream was never realized, so I pass it on to anyone who wants to make it... :)
Find three clear rings (plexiglass, resin, whatever type of ring you can find) each one smaller then the next, then attach these by drilling a hole at two apposing sides, making sure the wholes are aligned, the middle ring will need four holes, two for the inside ring, two for the outside ring. Make sure they are perpendicular. Attach semi-transparent orbs around these rings (this can be done several ways, but easiest would be to cut the orbs in half and attach them to the rings with glue. (make sure you have room to rotate the rings inside each other with the rings) Also, remember the electrons must balance each other on the rings one at each opposite side of each other, and also remember only 2(n^2) atoms on each ring (where n is the ring number, 1, 2, 3 etc)
Now you can use leds to light up the rings which would light up the atoms, or you can use motors to rotate the rings.
I personally wanted to use magnetism to levitate the middle nucleus, but a simple rod/string across the inner most ring would be sufficient, though the nucleus would rotate along with the electrons (not a big deal since I don't think it is proven otherwise). If you could do the magnetism, your teacher would defecate, I am pretty sure.
Anyhow, whatever you choose, I am sure it will rock, and whatever you do, you should take a couple pictures and post them here so we can see your handiwork!
Good luck!