I initially developed this project about 10 years ago as a more practical alternative to the classic egg drop activity. As time has passed and I’ve tweaked it in a variety of ways, I’ve come to like it even more than the classic egg drop (and not just because of the easy clean up). Because Graham crackers are less expensive and easier to handle than raw eggs, it is possible to do extensive testing and multiple revisions of the packaging, which is an important part of the engineering process. Sending the Graham crackers through the mail adds a compelling real-world aspect to the project. Furthermore, mailing the Graham crackers adds an element of suspense and delayed gratification.
I don’t limit the quantity of building materials that students can use because I have found that this is often difficult to do from a classroom management perspective – the last thing I want to be doing during a lesson is counting the number of toothpicks used in a structure. Instead, I incentivize students to limit their material usage by rewarding the groups with the lightest and smallest successful structures.
Graham Cracker Drop:
Like an Egg Drop, but with Less Mess
• Do Now: Write down a definition of the word “brittle.” You may write your definition from your current knowledge or you may use a dictionary or glossary.
• Discuss: what traits do brittle substances have in common? How do they respond to impact? What are some examples of brittle substances/objects?
• Let students know we’ll be using Graham crackers today. Warn students not to eat Graham crackers during class. If everyone manages to successfully avoid eating their materials during class, everyone can have Graham cracker, peanut butter, and sliced banana sandwiches at the end of class. (Modify snack to accommodate allergies, if necessary.)
• Randomly divide class into lab groups.
Graham Cracker Drop: Pre-Testing
• Introduce the guided inquiry:
o For each type of protection, Graham crackers will be dropped from a height of 3 feet. Drops will be face first, edge first, and corner first. Protection will include reinforcing the Graham cracker with thin particle board and padding with folded paper.
o Guide students as needed to create clear charts for data collection.
o What would be a good control for this experiment? Discuss as a class. If needed, lead students towards the idea of dropping un-protected Graham crackers.
o Conduct experiments, collect data, and have a class discussion of the results.
Graham Cracker Drop: The Main Event
• Assign challenge: Design the smallest and lightest device that will allow a Graham cracker to survive an 8 foot drop using drinking straws, construction paper, tape, cotton swabs, paper clips, popsicle sticks, cotton balls, and rubber bands. Among all the groups that finish with an unbroken Graham cracker, the winners will be the students with the device that has the smallest combined weight and length. (Calculated by adding the longest dimension of the device, in centimeters, added to the weight of the device, in grams.)
• Require teams to draw a design prior to receiving their materials. When students have a finished and labeled plan, they may begin construction.
• Warn them that they will get a maximum of one Graham cracker to use during the construction phase and a second Graham cracker to actually drop.
• Encourage students to take photos of their finished devices with their phones. If any student does not have a phone, arrange for pictures to be emailed to him/her.
• When all students have built their devices, hold the Graham Cracker Drop.
• Reward the students on the winning team by giving each of them a Graham cracker wrapped as a present.
• Discuss the results (perhaps over Graham cracker sandwiches). Which designs were the most successful? Why do you think this is true?
• Write a reflection: How was your actual device similar to the device you drew in the planning stage? Were you satisfied with your device’s performance? What would you do differently next time?
Graham crackers, scale, rulers, drinking straws, construction paper, tape, cotton swabs, paper clips, popsicle sticks, cotton balls, rubber bands, gift-wrapped Graham crackers (as prizes), bananas and peanut butter (for a snack)
Mailing a Graham Cracker:
More Graham Cracker Protection, Now with Delayed Gratification
• Do Now: Imagine that you need to send a graham cracker to someone through the mail. How likely do you think it is that the Graham cracker will arrive whole?
• Watch a short video about how mail is delivered so that students gain an understanding of what their graham cracker will go through. https://youtu.be/bB7dhE_TW9g
• Check homework: Randomly select students to read their reflections about the last lesson.
• Randomly divide class into lab groups.
Mailing a Graham Cracker: Pre-Testing
• As a class, discuss the stresses that a mailed Graham cracker would be likely to face.
• Develop a way to test packaging for the ability to protect Graham crackers from bending. (If students don’t come up with a better alternative, place the edges of the Graham cracker on thick books and place a small weights in the middle to measure how much stress the Graham cracker can take before breaking.)
• Give each group 20 minutes to develop a system to protect Graham crackers from bending forces. Test them to see which ones are most effective (hold the most weight before the cracker breaks) and least effective (hold the least weight before the cracker breaks).
• Discuss the results. What can we learn from this testing? What characteristics should a Graham cracker mailing device possess?
Mailing a Graham Cracker: The Main Event
• Give students information on postal regulations (i.e., minimum and maximum dimensions, maximum weight, and address requirements)
• A single Graham cracker will be sent through the mail as either a letter or a large envelopes. The winning team will have the smallest and lightest package to arrive with a whole Graham cracker. (The winning package will have the smallest combination of length (cm) + mass (g).)
• Instruct students to address envelopes before filling them.
• Teams are given business envelopes, large envelopes (non-padded), drinking straws, construction paper, tape, cotton swabs, paper clips, popsicle sticks, cotton balls, and rubber bands.
• Once teams are finished building their package, weigh it and calculate the necessary postage.
• In writing, describe the process you and your partner went through to create your Graham cracker mailer. What do you think well? Do you expect your Graham cracker to arrive safely? What would you have done differently if you had more time or different materials?
• Draw a design for a package to successfully ship live fish through the mail. Label this design clearly, with particular attention to noting which materials are in the package. (Note: This is actually done, but we will not be sending fish through the mail.)
Graham crackers, scale, rulers, drinking straws, construction paper, tape, cotton swabs, paper clips, popsicle sticks, cotton balls, rubber bands, envelopes, stamps, video equipment
Receiving Graham Crackers:
Was Your Packaging Successful?
• Do Now: Swap your homework with someone else in the class. Study the other person’s package design and prepare yourself to describe it.
• Check Homework: Randomly select students to describe the package design of the person they swapped with. Confirm with the designer – was the description accurate? Talk about ways to make sure you communicate your ideas clearly.
• Read description of how live fish are professionally shipped “Once the animals in your order have been selected for shipment, they’re carefully placed in new freshwater or seawater of the proper pH and specific gravity inside multiple poly bags with thick liners to limit the chances of punctures or leaks. The bags are then filled with pure oxygen and sealed with a special aluminum fastener for an air and watertight seal. From there the bags are placed in special insulated coolers to maintain a stable temperature during the transit, and warmers or ice packs are used to compensate for extreme temperatures depending on the season. The cooler is placed in a corrugated cardboard box for proper identification of the contents, and then the package is shipped next day air to arrive at your door the following day. Live Freshwater Plants, Pond Plants and Live Foods ship 2nd Day Air.” (liveaquaria.com)
Wrapping Up Graham Cracker Mailing Project
• Measure and record length and mass of each package. Allow each pair of students to open their package in front of the class. Record if the Graham cracker is whole or broken.
• Based on results, award winners gift-wrapped Graham crackers.
• Based on your experience with this project and your experience using many packaged products throughout your life, what are some important considerations that package designers must take into account? Discuss at least 3 considerations and how they may be handled.
o Have a variety of packages in the classroom for students to refer to.
o Conduct a brief class discussion and brainstorming session around this writing topic to ensure that students fully understand it.
o Give student 30 minutes to write.
o Assign each student a partner with whom to swap their rough draft. Remind students what constructive criticism is. Give students 10 minutes to provide written constructive criticism to their peer.
o Give students additional time to revise their essay. They may turn in the essay at the end of class or at the beginning of the next class.
• Option to complete “Packaging” essay.
Packaged Graham crackers (post mailing), scale, rulers, gift-wrapped Graham crackers (as prizes), variety of packaged products