I seem to recall seeing a documentary several years ago shot at a high frame rate (that is, played back in extremely slow motion) that showed when objects fall to the ground (think glass, etc) they don’t break on immediate contact. Rather, they bounce ever so slightly and break on the second contact with the ground. When discussing this with a friend of mine, he simply didn’t believe it, and it’s been too long since I saw it for me to swear that it’s true. Anyone know anything about this?
I don’t know about other things but when I worked in a dept store during X-mas I had the great fun of getting rid of glass orinments. I think I dropped one on accident and it bounced once then broke when it hit the ground the second time. I thought it was a fluke so I tried a number of times and they all did the same thing. I found that they could bounce a few inches off the ground and break on the coming down again.
perhaps the first bounce produces hairline fractures in the object which break upon the second bounce.
Edward, you really should have conducted a test. Drop a glass ornament, but have someone catch it after the first bounce. Then drop it again. Does it break this time before bouncing, or does it still bounce then break?
My guess is that the first time it strikes the ground, it stretches the object to its elastic limit, so it bounces instead of breaking. If the second bounce occurs before it regains its shape, it breaks. In the case above, I would guess the twice dropped ornaments would still not break until the second bounce.
I would also guess that a drop at sufficient momentum (i.e., from a greater height) would cause the object to break on the first bounce.