Why Are We Doing the Egg Drop Lab?
The Job
The job of a Mechanical Engineer does not end at the workshop or at the manufacturing plant.
Once the parts are manufactured according to the specifications, proper care should be taken in
packing the products for transportation. Poorly packed products lead to breakage, distortion, or
improper functioning of the part. There is a strong need to pack these products properly to
survive transportation, stacking etc. A well packed product also enhances the image. Keeping
these points in mind, your job is to design a housing for your egg. The housing should be
designed in such a way that the egg will survive being dropped from the maximum height
possible. Build this housing by making use of the materials provided. You are also advised to
team up with 3 or more students to work on the experiment. When the designs are complete each
group’s housing will be tested by dropping the housing along with the egg inside from
incremental distances until the egg breaks. Remember, if cost of material is a factor, then you
will be attempting to design the best egg drop apparatus at the lowest cost.
Physics Background information
When the egg reaches the ground, the falling egg has a large amount of downward
momentum and it must get rid of that downward momentum in such a way as to not break. The
solution to the problem becomes one protecting the egg by extracting its accumulated downward
momentum gracefully.
To stop, the egg must transfer all of its downward momentum into something else, such
as the earth. It can transfer its momentum into the earth by exerting a force on the ground for a
certain amount of time. A transfer of momentum, known as an impulse, is the product of a force
times a time, [Force x Time]. To transfer the momentum from the egg, the egg can exert a large
force on the ground for a short time or a small force for a long time, or any combination in
between. If the egg hits the bottom unprotected, it will employ a large force for a short time
which will most likely be very bad for the egg. That is to say, the bottom surface will push back
on the egg with an equally strong but oppositely directed force causing the egg to crack.
The best option is to increase the time of the impulse, thus decreasing the force. Also, the
egg will fare better when the force is distributed evenly [symmetrically] over the entire surface
of the egg. That is to say, the egg also has pressure from within itself pushing outwardly. If the
two forces are equal, the egg will not break.
To make the transfer of momentum graceful enough to leave the egg intact, a protective
package must prolong the momentum transfer and symmetrically distribute the force of impact.
The longer it takes for the egg to get rid of its downward momentum, the smaller the forces
between the egg and the slowing materials. Landing on a soft surface will prolong the
momentum transfer and help to reduce any localized [peak] force on the egg. Symmetrically
distribute the slowing forces uniformly on the egg. It is a very important aspect of the
experiment. Even a small force can break an egg if it's exerted only on one point of the egg.
The Egg Drop Contest:
1. There will be several drops from various heights. Your egg must survive lower
heights to progress to the highest! We will try a few smaller heights before the drop
from the second floor of TMA. Only those who survive (not leaking) the smaller
drops may proceed to the higher levels.
* A cracked egg is defined as one that is visibly leaking its contents (did not
survive). Hairline fractures are not considered cracks and may go on to a higher
level.
2. After each drop, you must be able to quickly open the container to show your egg.
Your grade will drop if not able to open quickly!
3. Container must be constructed with a hatch or a door so that the egg can be inserted or
withdrawn quickly. The contestant will be required to remove the egg from the
container to show judges that it did not break.
The Rules:
1. The main egg compartment cannot be bigger than 10 x 10 x 10 cm. All parts
MUST fit within 25 x 25 x 25 cm. Your device will be measured before dropping.
2. The container can be of any design, but may NOT include ready-made packaging
materials (bubble wrap, styrofoam, peanuts, etc.)
3. The total empty device may have a mass no greater than 600 grams.
4. A raw large egg will be provided.
5. The container must free-fall (no parachutes, nor helium balloons). Wings are
allowed, but device should descend straight down, not to the side.