Bob Steele: I think you are probably right, about the chips becoming attached back to the magnet, and then the blue shavings. (We were wondering what the blue shavings were, haha)
We did try using a bigger drill bit, which did succeed getting through some of it, (I used a 1/2 inch bit) but because that is almost the size of the magnet... heh.
As for the 2 destroyed drill bits: They were NOT new ones, they were several years old, and we have at least 2 more of the same size.
And for the physics course, that's true, but where is the experimentation with that?
(Besides, I haven't taken physics yet, sadly. Not open for me until next year. )