There's a binary color device on this website that will teach her binary as well as logic gates, just go to "Eye Openers" from the main page and scroll down and find it (or Ctrl F it). I've seen it help a lot of Electrical Engineering students convert between binary and decimal in their heads.Also, I made a training device that used marbles and leverage to describe binary when I was in community college.
I got a 5/16" piece of brass (hollow square stock) that was about 2' long (I think) and drilled holes with the following spacing.
|.25"|1"|1"|1"|2"|4"|
Anyway, once I got the holes drilled, I used brass rods (I think about .040" thick) to make a hook for the "center" (the second hole from the end) and little marble holders for the four holes to the left of the center. This isn't really the center, but it is where the thing will pivot.
For the hole to the right of the center, I used a plastic tube that was wide enough to accomidate marbles and long enough to hold fifteen of them. I ended up at a pet store buying aquarium tubing, I don't remember the diameter.
Once the thing is balanced (I used a brass weight and a left-over piece of the brass rod) one marble in the tube has the same affect as one marble in the first holder on the left side. Two marbles in the tube has the same affect as one marble in the second holder on the left. Four marbles in the tube has the same affect as one marble in the third holder on the left. This will work on any combination of number between 0 and 15.
It works on leverage. Since we calculate moments (turning force) as force times the perpendicular distance, one marble two inches from the center has the same moment as two marbles one inch from the center. So if I put a marble eight inches from the center, I would have to use eight marbles one inch from the center in order to balance it out.
I'm out of town right now, but I will post a picture when I get back home.
--CS