The purpose of this activity is to recreate the classic egg-drop experiment with an analogy to the Mars rover landing. The concept of terminal velocity will be introduced, and students will perform several velocity calculations. Also, students will have to design and build their lander within a pre-determined budget to help reinforce a real-world design scenario.
Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standard Network (ASN), a project of JES & Co. (www.jesandco.org).
In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.
Click on the standard groupings to explore this hierarchy as it applies to this document.
- Colorado: Math
- Colorado: Science
- Common Core State Standards for Mathematics: Math
- 2. Fluently divide multi-digit numbers using the standard algorithm. (Grade 6)  ...show
- b. Solve unit rate problems including those involving unit pricing and constant speed. For example, if it took 7 hours to mow 4 lawns, then at that rate, how many lawns could be mowed in 35 hours? At what rate were lawns being mowed? (Grade 6)  ...show
- International Technology and Engineering Educators Association: Technology
- Next Generation Science Standards: Science
- Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions. (Grades 6 - 8)  ...show
- Students should understand that objects accelerate as they fall.
- Identify several components of a Mars lander designed by engineers.
- Design and build an egg-lander within a confined budget.
- Define and understand terminal velocity.
- Recognize similarities and differences between their model lander design and the Mars Landing Spacecraft design.
- One egg
- One Zip-Lock™ (or other "zipper" brand) sandwich bag
- Styrofoam or plastic cups
- Low-density foam (available at most fabric stores)
- Pack of balloons
- Tape (masking or transparent)
Before the Activity
- Gather all necessary materials.
- Make enough copies of the Egg-cellent Lander Order Form for each group to have one copy.
- Designate a testing area with a hard landing surface (i.e., tile or concrete) to drop the student's egg-landers (a balcony, window, or even a ladder work perfectly).
With the Students
- Challenge each student group to design a safe landing craft for their raw egg.
- Explain to the students that each group only has $1 to purchase materials.
- Pass out one Egg-cellent Lander order form to each group.
- The groups should sketch their design on their order form before they pick up their materials.
- Pass out one egg to each group. Have the groups immediately place their egg in a zipper bag to prevent any accidental messes.
- Allow the groups time to build their egg-landers.
- Test the egg-landers in the designated area.
- A group will have successfully completed the mission if their egg remains unbroken after the fall.
- Ask the students to come up with some ideas on how to safely land a delicate falling object like an egg. (Possible answers may include: padding or foam, airbags or balloons, springs, parachutes, etc.).
- What two types of engineers would most likely work on building a lander for a delicate and expensive falling object like a Mars rover? (Answer: aerospace and mechanical engineers)
Activity Embedded Assessment
- When falling, a balloon will immediately reach its terminal velocity. Drop a fully inflated balloon from 5 feet and record the time it takes to hit the ground. Have the students calculate its terminal velocity by the simple equation,
- Have students explain the best part of their design and what could go wrong with it (and what could be fixed in future models). Remind students that engineers go through the deign/build/redesign process many times before they arrive at a finished product.
- If the balloon used in the Embedded Assessment was only inflated one-half the amount and still dropped from a 5 ft. height, would it hit the ground in more or less time? Would its terminal velocity be slower or faster? (Answer: The balloon would take less time to hit the ground, and its terminal velocity would be faster. Because the balloon has a smaller area when it is deflated, it will experience less drag.)
- If a coin were taped to the fully inflated balloon to add more weight and dropped from a 5 ft. height, would it hit the ground in more or less time than the inflated balloon without the coin? Would its terminal velocity be slower or faster? (Answer: The balloon would take less time to hit the ground and its terminal velocity would be faster. A heavier item has a faster terminal velocity than a light item of the same aerodynamics.)
- We performed the egg-lander experiment on Earth rather than on Mars where the atmosphere is much thinner. What problem could this present if we tested our designs on Mars? (Answer: Because the atmosphere is so thin, the lander would not come close to reaching its terminal velocity, which is very fast. Instead, it would keep gaining speed while falling until it finally hits the ground.)
- Additional materials not listed in the Materials List may be purchased and added to the Egg-cellent Lander Order Form if a more difficult and diverse selection is desired. For example, both large and small balloons could be purchased.
- Prices may be adjusted in the Egg-cellent Lander Order Form to make the design more challenging. For example, balloons could cost twice as much as foam.
- In order to make the terminal velocity harder to reach, do not allow the groups to fully inflate their balloons.
Chris Yakacki, Geoffrey Hill, Daria Kotys-Schwartz, Malinda Schaefer Zarske, Janet Yowell
© 2004 by Regents of the University of Colorado.
Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Last modified: September 3, 2015