The outward expulsion as the bullet enters is due to the material being pushed to the side and sliding back up toward the lower pressure area which is behind and to the side of the bullet - initially following the contour of the shock wave in front of (round nosed bullet) or attached to the nose of the bullet (pointed bullet). Behind the bullet and it's shock wave, there is a vacuum as the bullet passes, the now emulsified apple material rushes in to fill the void. When the material comes back together, some follows the bullet, some shoots backward to dissipate the energy that was generated in the collapse back into the void behind the bullet. It's a bit like dropping a pebble into a pond, but more dramatic and considerably faster. Some water sprays up and to the side, after the pebble has entered the water it leaves a "hole", water rushes in and a second vertical spout occurs. Watermelons and hypersonic bullets are much more dramatic. Regards, Bob.... -------------------------------------------------------------------- "Beer is proof that God loves us and wants us to be happy!" - Benjamin Franklin From: "ADavidhazy" <ANDPPH@ritvax.rit.edu> > Hi Greg, > > The collection of photographs hopefully will give the faculty some incentive to > get a little more involved with web activities. Most do not have even a > rudimentary personal website to this date! This little project is my personal > "contribution" to get my colleagues to become a bit more "connected". We will > see what "develops"! (what is the equivalent in digital realm?) > > > Do you know why an apple explodes out both the entry and the exit point when > > you shoot it? Seems to me it would only blow out the exit hole but the photos > > show otherwise. > > Well, I think it takes a physicist to really explain it but I believe that the > stuff that goes out backwards is caused by the material, early on in the event, > not being able to go forwards (too much apple ahead) and the area or direction > of least resistance for stuff the projectile pushes out of the way is > backwards. Eventually the front rips open and then material is pushed and also > carried forwards by the bullet. > > > By the way that string shot is fabulous, no, marvelous, no, > > stupendous! Is 'stupendous' really a word or a coined marketing phrase? > > Actually it is a set of tightly stretched rubber bands. The top and bottom > parts of the bands don't yet "know" that the middle has been cut away. Doc > Edgerton did similar things with string and Loren Winters has a photo of a > single rubber band or sheet photographed in sequence by 8 different flashes > with different color filters on each for a stunning image. > > Stupendous is a word. It is most often associated with my picture of a bullet > cutting a series of rubber bands! :) > > Andy > >
