Railworks America

Hello all. I know there are a lot of intelligent individuals that cruise through the forums here and I have a very off topic and off the wall question I would like to pitch to you all. I am helping my son out with a science project; his teacher is asking the class to design a container that will protect an egg from a 500' drop. That's right, 500'. He is a pilot and is going to drop the containers the students design out of his airplane. I have done a bit of research on egg drops, but they all refer to experiments from 25' or less. 500' is a big leap. We tried something earlier, but ended in failure; we used a Sunny D jug, some pillow filling and some almost microscopic Styrofoam beads. Splat!! If you can help out, my son and I would greatly appreciate it. Oh, and the egg cannot be hard boiled.

Sure - first hard-boil the egg...

Well, I'm not intelligent, but I think I'd try something like what engineers use on race cars. Some kind of frame that will absorb the energy and deform but keep an internal cage relatively safe. So, I'd think you don't want to cushion the egg, but build a crushable container that will absord the energy of impact as it collapses. Sorry I can't think of any more concrete suggestion. Perhaps a little googling that sort of thing would give you some ideas.

emdsd90mac wrote:Hello all. I know there are a lot of intelligent individuals that cruise through the forums here and I have a very off topic and off the wall question I would like to pitch to you all. I am helping my son out with a science project; his teacher is asking the class to design a container that will protect an egg from a 500' drop. That's right, 500'. He is a pilot and is going to drop the containers the students design out of his airplane. I have done a bit of research on egg drops, but they all refer to experiments from 25' or less. 500' is a big leap. We tried something earlier, but ended in failure; we used a Sunny D jug, some pillow filling and some almost microscopic Styrofoam beads. Splat!! If you can help out, my son and I would greatly appreciate it. Oh, and the egg cannot be hard boiled.

Will the egg float in water? If so, put the egg in the jug filled with water. I am wondering if the sudden stop at the drop would cause the egg to be pulled down towards the bottom of the jug, but is decelerated (gently?) by the frictional mass of the water. A thick silicone grease might also work. The decelerating force of the dropped jug must be moderated below the breaking force placed on the shell of the egg somehow. Also, if this decelerating force is distributed evenly around the surface of the egg, perhaps by a fluid such as water or a heavy grease, this may work.

The force needed to break an egg, if distributed evenly around the surface of the egg, is greater then if it were applied to one point on the egg...

Just a thought...

Maybe surround it with a "net" made of rubber-bands to help absorb and disperse any impact? I dunno, just throwing out some idea.

Try building a spherical exterior shell. You could use two metal salad bowls. A sphere will absorb impact energy equally on all sides.
Is there a size limit to the exterior container?.

A thick goo filled ball would probably do it - you just want to stop the egg decelerating too quickly, and attempt to keep the pressure on the inside of the shell the same as the outside. Also not to apply a shock to any part of the shell, which is what breaks 'em. Is there a limit to the size?

Other ideas are something like one of those inflatable ball things you can get in and float, or a styrofoam container and a bunch of balloons ( although you might not ever find that one! ). Are there any limits to this "container" design?

Yes, the size limit is 10" X 10" due to the size of the window on the aircraft it's being dropped out of. I am now considering using a plastic 1 gallon gas can filled with gelatin. At 500', I know the container will break, but I am hoping the gelatin will provide enough energy absorption to allow for the eggs survival. But that leaves me with one other problem and that is terminal velocity; the heavier I make it the greater the terminal velocity equaling in a higher impact speed. Friday is the drop and it will be interesting.

Hmm, a very difficult issue.
As I did the egg throw experiment on a school excursion long ago, I know how difficult this is even at much lower heights.

A solution of enclosing the egg with water was proposed and that also was my first thought.
However, if you jump from very high into water you will be hurt severely or even be killed because at a certain impact speed, the water surface has the same nature as a concrete floor.
On the other hand, it might be different for sth. already enclosed by water.

But then how do you prevent the egg from too much movement inside the container so that it eventually not bursts from hitting the sides? What use as a good suspension?

I'm also sceptical about the use of other fluids such as gel.

I'd say that it is impossible to make this experiment a success.
The final speed and impact force caused by a drop of such a height seems to make it impossible. As everyone knows, eggs are very fragile and I think that 500' is simply way too high.

EDIT: But I'll ask a friend who's studying aeronautics and space technology.
There's a lot of maths involved and he might have a solution.

I'm wondering if putting the egg in a balloon or two ( not inflated ) to pre-stress the shell might help. Attaching it inside the container with some stretchy rubber to act as brakes and to keep it central would mebbe help a bit too, but that's getting pretty complicated :)

It needs to be pretty thick gel or the egg will just move through it and hit the edge of the container when it lands. Might be a better idea to try gradually thicker foam, thinnest nearest the egg.

Syrup, on Mythbusters they showed how hard it is to move through that stuff, fill the container with a mixture of syrup and maybe some molasses, that'll keep it from breaking.

Csxgp38-2 wrote:Syrup, on Mythbusters they showed how hard it is to move through that stuff, fill the container with a mixture of syrup and maybe some molasses, that'll keep it from breaking.

But will the suspension capability of such a viscous material be enough or will it just be compressed strongly by the sudden impact so that there is too much resistance to the egg?

Maybe also put the egg surrounded in the center of several partially inflated balloons, is this may act as a type of "air cushion" that could protect the egg.

micaelcorleone wrote: But will the suspension capability of such a viscous material be enough or will it just be compressed strongly by the sudden impact so that there is too much resistance to the egg?

I guess the only way to find out would be to do a scale test, small container full with 1 egg from as high up as possible and drop it, then if it breaks from 50 feet or whatever, it probably won't stand a chance at 500 feet.

Ok, so I have come up with this idea. Since I feel this is nothing more than an experiment in critical thinking and therefore an impossible task, I am going to use bubble wrap. A 10" by 10" cylinder of bubble wrap with the egg in the middle might do the trick. It provide excellent impact protection and is light weight enough to keep impact speed to a minimum. I don't know what the forecast is for the day of the experiment and I do not know where the "drop zone" will be. It's winter, we live at the base of the Sierra Nevada Mountains, so it's a bit chilly here. Cold air is more dense and will create more drag as the object falls. If we use a lighter weight vessel it won't achieve a high impact speed. I want to thank everyone for their inputs so far. I will be sure to pass on the final decision and results.