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Homework Help: Naked Egg drop

  1. Oct 27, 2011 #1
    So. This annoying project attack's again. I have to create a box to catch an unadulterated egg at the base of my school balconies. Starting at 18 ft. I have no clue were to even start! worse part, its due very soon and my 'group' refuses to help. I do not know what to do. my only limits are the egg must be raw with nothing attached and my box can not be bigger than 12in*12in*12in. If the egg breaks in any way, I fail. PLEASE HELP ME!!!!!

    Crazed AP student.....
  2. jcsd
  3. Oct 27, 2011 #2
    What are some things that you can do to decrease the impact upon collision?
  4. Oct 27, 2011 #3
    I would consider using a dense cotton wool layer perhaps suspended on a stretched latex type of "trampoline". The egg cotton wool will absorb some KE, so will the latex, but the egg my bounce back up some height and back down on the trampoline for a few cycles until all the KE is eventually dissipated.
  5. Oct 27, 2011 #4
    I bet viscious liquid would work--fill a plastic box with honey or something similar and maybe pad the bottom with something soft.
  6. Oct 27, 2011 #5
    Surface tension of the fluid would be enough to probably crack the egg. The egg would crack on impact at the speed it would have dropped from 18ft. The more viscous the fluid, the "harder" the initial impact.
  7. Oct 27, 2011 #6
    Do a test run with a couple materials. You should be able to develop some idea as to which materials will work, and which wont.

    It can go numerous ways. The material could be elastic, and hence provide an oscillating egg that is damped exponentially. Moreover, this effect could be a bad approach as the egg experiences an impact force every bounce.

    You may also want something that absorbs the kinetic energy almost fully, but slowly retains its original shape such that it does not produce a bounce. This could result in too much of an initial impact.
  8. Oct 28, 2011 #7
    Experiencing an impact force every bounce is definitely not going to be a problem, as long as it can survive the first impact and bounces back on the trampoline with each subsequent oscillation! If the egg is going to crack on impact with anything, it will be when it first hits the absorbing surface. Each impact after the first will be less then the one before it.

    One thing to consider however is to try try and drop the egg such that its strongest surface impacts the absorbing material...ie. the smaller radiused end that lies along its axis of symmetry.
  9. Oct 28, 2011 #8
    That's not entirely true. The shell can be weakened after the first collision, and its strength would decrease further upon subsequent collisions.
  10. Oct 28, 2011 #9
    Why not put a soft foam on top of a viscous fluid? Or layer fluids?
  11. Oct 28, 2011 #10
    An egg shell is not the type of structure or made of a material that progressively/gradually gets weakened with every impact.

    Being a brittle structure, once an impact threshold is exceeded, the integrity of the structure is as good as compromised and catastrophic failure soon follows (if not immediately). Once a crack forms it is essentially game over.

    Impacts below this impact threshold (that do not result in any cracking) have no effect at all on reducing the strength of the structure/the impact threshold when considering the effects of subsequent impacts.
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