Re: Resubmitted: Marble breaks Coke bottle; steel bearings-never...(?)

 My guess is that since marbles and coke bottles are
ceramics, they are virtually non-compressible, and therefore the impact
creates a stress _point_ at which the energy is concentrated propagating a
stress fracture in both structures.  Steel however, is malleable and
therefore, even though it _seems_ just as hard upon casual observation, it
actually "gives" and absorbs some of the impact.  Check your ball bearings
carefully before and after the event.  You should see a small dent or mark
on it where it hit.  If you have a good loupe or microscope to examine it
with you will probably be amazed at how much it has deformed at that spot.
Let me know if this proves to be the case.

Rick