The Egg Drop Challenge! Dun dun dun...
At my school, our teachers challenged us to build a device that would protect an egg when it was dropped from an 18 foot high balcony. The goal of the challenge was to learn how 3 of our classes (engineering, physics, and algebra) fit together. It's easier to see connections in real life (ish) challenges than on a worksheet.
We started out by getting into groups and assigning roles. I was the team lead, Riana was our builder, and Julianne was our documentarian. We mostly stuck to those roles, but since we only had three people, we helped each other out a lot, especially during the build part.
Step 1: Identifying Needs and Constraints
We were given a limited list of materials:
- Hot glue
- Hot glue gun
- Packing peanuts
- Paper clips
- Cotton balls
- Pipe cleaners
- Rubber bands
Our egg-saving device had to be less than 12" by 12" by 12", and we had one class period to come up with our design and list of materials. We also had 3 more class periods to build the device, one to test it with a plastic Easter egg, and 2 more to make adjustments. Then we would do the final drop.
Step 2: Research the Problem
After doing some research, we found that there are three main categories of egg-saving devices.
1. The first absorbs the force by putting materials like packing peanuts, cotton, or newspaper around the egg to prevent the egg from having to take much of the force. It is pretty basic, and just involves stuffing a box with packing materials. However, most designs incorporate some aspect of this category.
2. The second minimizes the amount of force that is put on the egg by slowing its descent. This is usually accomplished with balloons or a parachute. We didn't have access to balloons, so if we wanted to use this type of design, we would have to make a parachute out of newspaper.
3. The third design for egg-saving devices uses suspension to direct the force elsewhere. Usually, it works by suspending the egg inside of a container with rubber bands or some other elastic material. This design looked more difficult than the others, but it was by far the coolest looking.
Step 3: Develop and Select a Solution
Our group knew right away that we didn't just want to stuff some newspaper in a box and call it a day, so we decided to make our egg-saving device with the third type of design: suspension.
We decided that we would have the egg in a 4" cube with packing peanuts, and that cardboard box would be suspended inside of a 10" cardboard cube by rubber bands from the corners of the little box to the corners of the big box. We used two rubber bands per corner and lined the inside of the big box with packing peanuts, just in case.
Our group knew that this design was going to be fairly difficult, but we felt like it would teach us the most about physics and engineering.
Step 4: Create a Prototype
Making the egg-saving device was, as expected, the most difficult part of the challenge. We were given two days to build, which we knew was already going to be tight, but on the first day, we didn't have packing peanuts.
Day one, we started out by making two nets: one for each cube. We weren't able to assemble them until we were ready to suspend them because we wanted to make sure that the rubber bands were as secure as possible. We finshed the nets with about 15 minutes to spare, but until we lined the larger box with the packing peanuts (that weren't there), we couldn't finish.
Day two, we had packing peanuts and worked as quickly as we could to line the larger box. Once we finished, we started working on assembling the boxes with the rubber bands, but we ran out of time. Because the teachers gave us the packing peanuts late and a majority of the groups weren't ready, they gave us one extra day.
On the final day, we were able to finish our project.
Step 5: Test and Evaluate Prototype
We tested our prototype by dropping it off of our school's balcony. We weighted a plastic egg with rocks to make it closer to the weight of a real egg. The egg was placed in the smaller box, and we pushed it off of the balcony. After, we quickly ran to the box and opened it up to discover...that we had cracked our plastic egg.
The next day, our teachers had us test the prototype with a real egg. Our group already knew the outcome, so we put the egg inside a plastic egg before placing it the egg-saving device. When we opened up the box, we discovered that...the egg survived! We weren't entirely sure why, but we think it's because the weighted egg was too heavy.
Step 6: Improve and Redesign Prototype
Even though the real egg survived, our team still felt like we should make some improvements to the egg-saving device. It had also taken quite a beating after being thrown off the balcony so many times.
We reglued the packing peanuts on the inside and tightened the rubber bands. Then, we reglued the box. We finished fixing the prototype early, so we added some drawings to the outside.
Step 7: Test and Evaluate Final Design
It was time for the final drop. We said a prayer and set the egg in the smaller box, hoping that the egg-saving device wouldn't become its final resting place. We pushed the egg off of the balcony, and the landing was so loud that everyone was sure that the egg had shattered. However, when we looked inside, the egg was fine!
We finished up by calculating the egg's momentum, force, and speed, among other things. We created a lab report and presented the project to the rest of the grade. We decided that our design was effective, and we would recommend the Egg Drop Challenge to others.