Naked Egg Drop
Student pairs experience the iterative engineering design process as they design, build, test and improve catching devices to prevent a "naked" egg from breaking when dropped from increasing heights. To support their design work, they learn about materials properties, energy types and conservation of energy. Acting as engineering teams, during the activity and competition they are responsible for design and construction planning within project constraints, including making engineering modifications for improvement. They carefully consider material choices to balance potentially competing requirements (such as impact-absorbing and low-cost) in the design of their prototypes. They also experience a real-world transfer of energy as the elevated egg's gravitational potential energy turns into kinetic energy as it falls and further dissipates into other forms upon impact. Pre- and post-activity assessments and a scoring rubric are provided. The activity scales up to district or regional egg drop competition scale. As an alternative to a ladder, detailed instructions are provided for creating a 10-foot-tall egg dropper rig.
Figure 1. Students pose with their egg catcher.Copyright 2015 Denise Jabusch, University of California Davis
Engineers must understand well the concepts of energy transfer, conservation of energy, and energy dissipation in order to design uncountable real-world projects. They also need to understand the properties of materials in order to design complex systems. Materials can dissipate energy through various means, such as heat, light, and vibration. For example, engineers design skyscraper foundations using concrete and steel so that any given foundation can withstand the huge force of the building it supports as well as the dynamic forces it may experience during earthquakes. Engineers who design computer keyboards want to select a material that can be repeatedly tapped, can be easily and permanently be printed on for the letters, feels good under finger tips, is inexpensive and environmentally benign, and is cleanable. Identifying the materials that help to meet project constraints is an important aspect of the design process.
After this activity, students should be able to:
- Explain the transfer of potential to kinetic energy of a dropped egg and explain where the energy goes after it hits the egg catcher.
- Explain why some materials are better than others for absorbing the kinetic energy of a falling egg.
- Describe the relationship between height and the kinetic energy of a dropped egg.
- Explain design modifications made during the design process, weighing factors such as height and materials.