KingradKong

You'd be better off with a team of physicists, geologists are only good with really big plates. ;)

Also an electron microscope wouldn't be the best tool for the job. I would worry that the electrons would eventually change the spin states of the magnetic regions erasing your data. You would need a decent flux/energy level of the electrons to get good enough imaging of the platter, which would mean dumping a lot of energy into it. Instead I would go with a Spin Polarized Scanning Tunneling Microscope. It requires much less energy at the interface (it is a tunneling current after all). Setting up an automated recording device to image the surface wouldn't be much work, though the scan would certainly take a significant amount of time, though you wouldn't need to do atomic level imaging, so the speed could be optimized. Likely you would need to modify your instrument with multiple scanning heads which could bring down the scan time to a reasonable amount of time.

Under very optimistic conditions you could get a whole 1TB platter read in 128 days with a single head. With multiple heads (I'd imagine you could quickly(6 months to a year) build an instrument with... 16 tips) resulting in an 8 day throughput per 1TB platter.

Then again the technique might require reading subsurface residual magnetic encoding. Meaning epitaxial removal of the magnetic material which has been zeroed may show a clear image of the old data. Then you would need to come up with a good method for each magnetic material used currently. Perhaps typical ion bombardment would be enough with enough tweaking of the parameters. Perhaps a solution phase removal would work.

I am a chemist. Want to send me a sample vial of your sweat so I can analyze what compounds are resulting in the colouration?

I think what you are doing is awesome! I remember, at age six, playing Super Solvers Outnumbered for countless hours! Now that I think about it, math was always a breeze for me throughout school and I can't help but think that my childhood gaming habit helped with that. Being able to incorporate these basic skills into a childrens game is a noble cause and I wish you the best! If this game works out as you had hoped, will you be continuing a 'learning' series of gaming or is something else in your future?