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Physics Project (Egg Drop, again!)

  1. May 9, 2005 #1
    I just got my project from physics, and its that annoying, classic egg drop situation. I have a lot of restrictions, and its out of 20 points, so its pretty hard. I would LOVE it if any one of you could maybe contribute any ideas and suggestions and such. Thanks a bunch!

    Restrictions and Point Deductions:


    Time of fall is less than 2 seconds= no deduction
    Time of fall is between 2 seconds and 4 seconds= -1 pt
    Time of fall is between 4 seconds and 10 seconds= -2 pts
    Time of fall is greater than 10 seconds= -3pts


    If landing and at rest within 40cm squared target area on the ground= no deduction
    If landing and at rest outside 40cm sqared target area on ground= -1pt deduction


    If final resting place of egg is within 5 cm of ground level= no deduction
    If final resting place of egg is between 5 cm and 10 cm off the ground= -1 pt
    If final resting place of egg is between 10cm and 35cm off the ground= -3 pts
    If final resting place of egg is greater than 35 cm off the ground= -4 pts


    Use of padding around the egg= -3 pts
    Use of catching device with a base greater than 400cm squared= -1 pt
    Use of catching device with a base greater than 1200cm squared= -2 pts
    Use of a catching device higher than 30cm= -1 pt
    Use of any type of casing/box/bottle/enclosing covering the egg= -1 pt
    Use of duct tape/any type of tape= -2 pts


    If egg cracks but does not leak= -1 pt
    If egg breaks and leakage occurs= -4 pts

    Engineering Effort

    If the device shows minimal effort/though= -5 pts

    !Remember that this project is out of 20 pts, so to get an A, I can only miss 1!

    (I just want to get some ideas of how other pros would do it, so suggestions and comments and idea would be greatly appreciated.)

    Thanks Again!
  2. jcsd
  3. May 10, 2005 #2
    From what height is the egg to be dropped?
    Is the way the egg is released restricted in any way? (who/what drops it?)
  4. May 10, 2005 #3
    Please clarify - I think you mean 400 square cm? As in a square with 20cm to a side?
  5. May 10, 2005 #4
    Each restriction is obviously directed at a few "clasic" solutions (pad the egg, slow the fall, pad the landing). I'm guessing that the best mark will be something that uses both permitted techniques, but to a limited degree...

    Add a parachute that slows the fall to just under 2 seconds, and ...
    Construct a catching device just under 400 square cm (?) and just under 30cm high, that ends up holding the egg just under 5cm from the ground.
  6. May 10, 2005 #5
    off a ledge on the second story of a gym. Not THAT high, maybe 20 feet, more or less...

    It is not restricted... I drop the egg, how many ways are there to drop an egg?

    Ya sry thats what I meant

  7. May 10, 2005 #6


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    Here's an idea and story for you. Indy racing has a lot of scientists/engineers working to make it a safer sport for the drivers. They noticed at one point many drivers were getting head injuries in rear-end accidents. Typical reaction would be to put more foam behind the drivers head for padding - wrong answer. The foam they were using had too much 'bounce' and was a contributing factor.

    So a deformable foam that offered a plastic collision (not elastic) would use up the kinetic energy in its deformation would also allow the egg to be closer to the ground as it deformed, a 2-for-1 deal!

    Styrofoam (expanded polystyrene) would be a good choice and comes in different densities that would offer different characteristics. Does that count as padding? Hopefully less than regular egg-crate foam would.
  8. May 10, 2005 #7
    ya, any type of Styrofoam would be considered a padding. I just learned that fluids and gas are NOT considered padding. Soooooo..... I was thinking about maybe a pool or something. Also, to solve the accuracy issue, a net with a sag in the middle would make the egg roll to the middle, erasing the issue of accuracy.
  9. May 10, 2005 #8


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    You mean an airbag is allowed but styrofoam isn't?

    As Smokey Yunick of NASCAR fame would say, "it ain't cheating if you don't get caught"

    Its been years for me, but I think I'd challenge myself to use my old Dukes of Hazzard lunchbox as the container with little more than the sandwich bags and some bread and see if I could pull it off. Gotta have a challenge ya know! :smile:
  10. May 11, 2005 #9


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    Dukes of Hazzard? I had a Star Wars lunch box. Damn I wish I still had it.
  11. May 11, 2005 #10


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    My mom thought Star Wars would be a violent influence. So instead my fragile little mind was influenced by a TV show about moonshining, running from cops, and driving like a manic. :smile:

    Besides, they had a Dukes of Hazzard reunion here in Atlanta last year, Cooter was a GA congressman for a while, has his own musem in some resturant with a few hundred peices of memorabilia, and there's a new movie coming out that Rhys Millen was a stunt driver in staring Johnny Knoxville, Stifler, and Jessica Simpson. Go to an automotive event down here in the south and you're bound to learn all kinds of minutia.

    I'm curious what the OP has come up with for a plan.
  12. May 12, 2005 #11
    Uh, I know a way to go about this that would only lose you one point. You'd have to use a box, see, is the problem. But other than that, everything else is legal.

    Again, as the person said earlier, I'm pretty sure this innovation was come up with for race car drivers. The driver is strapped in a seat that is suspended on all sides.

    So. You build a box of wood or somesuch, doesn't really matter so long as it's stable, wrap the egg in a twist of nylon (women's stockings, for example) and nail the ends of the nylon twist to opposing sides of the box. Alternately, do the same thing with a box but stick the egg inside some sort of egg-shaped plastic container in the middle and string it up in the center by elastic bands stuck to each of the eight corners. (This is the professional way to do it, and probably a bit more expensive/hard to come by. I like the nylon one, and it works most of the time.)
  13. May 13, 2005 #12
    I like that idea, but I think it would be hard to make it land acurately. You could perhaps add some streamers or some kind of open parachute to slow the fall slightly and stop the box from tumbling... that might make it land squarely. Perhaps a catching device could also be used?
    It might be tricky (but doable, I think) to have the egg finish less than 5cm from the ground.
    As far as the encasing rule goes, what if you used a rigid but open cage instead of a box? Like a cubical frame made of aluminium?
  14. May 13, 2005 #13
    frames count as an inclosing :grumpy: :mad: :devil:
  15. May 13, 2005 #14


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    -1 pt deduction? so --1? so +1? :tongue2:
  16. May 13, 2005 #15


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    Offhand I'd try a combo solution as was previously suggested - a small pan of water, less than about 10" deep (25 cm), below the minimum area specified, with some sort of soft rubber/jelly pad at the bottom of the pan, up to 2" worth (5 cm). (You might be able to use jello, but I think water on top would dissolve it). Design a parachute system that will allow you to reliably hit the pan of water without exceeding the time limit. You'll probably have to glue the egg to the parachute lines, I suppose. Add an aiming system ( a long string and a weight will do) - if you're really paranoid, make the parachute follow the string down so you know you'll hit the target (who knows how windy it'll be?).

    Egg drops, water splacshes, and hopefully it hits the rubber/jelly pad slowly enough not to break.
  17. May 14, 2005 #16
    I'd start by finding what an egg can actually take - in terms of impulse. Add an adequate safety margin too.

    Then I'd make a device that catches the egg and slows it down without exerting a greater force than the egg's greatest allowable impulse.
  18. May 29, 2005 #17


    I tried this with a cardboard box and it worked!

    now i only have to find a way to make it be 5cm off the ground, so a smaller box, and a smaller box to fit into the target!

    thanks for the idea, though!
    Im gonna use it, I threw it down as hard as i could, and it didnt crack. Same with throwing it down off of my 2nd story roof. Thank god for my moms stockings!

  19. May 30, 2005 #18
    How's the landing accuracy? Can you nail a 40cmx40cm square?
  20. May 31, 2005 #19
    well, ya thats the hard part....

    i decided since it bounces away off the target, I put a cardboard box within the limits and will land it in there
  21. May 31, 2005 #20


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    I think you found the problem with elastic materials - bounce! A material that deforms would not have a bounce.

    You could try using a high viscosity liquid like pancake syrup. You then may need to figure out the density - in water the egg would sink, meaning that only the bottom surface of the water would need to be 5cm from the ground. The syrup may or may not have a higher density so you may need to find something else. Your mom should love such experiments in the kitchen.... :smile:
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