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Egg Drop

In this demonstration, students discover a practical way of determining whether or not an egg is raw or hard-boiled.

The Classic "Egg-Drop" experiment has been a standard in science instruction for many years. Essentially, students are asked to construct some type of container that will keep a raw egg from cracking when dropped from ever-increasing elevations. In this exploration, students design, evaluate, and suggest improvements for a container that will protect their precious payload: an egg.

There are three basic ways to increase the likelihood of safely dropping an egg:

  1. Slow down the descent speed.
  2. Cushion the egg so that something other than the egg itself absorbs the impact of landing.
  3. Orient the egg so that it lands on the strongest part of the shell.

Parachutes are an obvious method for slowing the decent speed, as long as the design includes a way to keep the parachute open.

The largest end of the egg has an area of air trapped between the egg's two membranes. This air space forms when the contents of the egg cool and contract after the egg is laid. It accounts for the crater you often see at the end of a hard-cooked egg. Upon impact the heavier spherical yolk continues moving towards the ground. The compression of the airspace acts like an air bag for the eggs' valuable contents. Building an artificial cushioning device will also help absorb the impact of landing.

The arch structure at either end of the egg is stronger than its sides. Pressure is distributed down (or up) the arches so that less pressure acts on any one point. Orienting the arch downwards will increase the egg's survival.

On August 22, 1994, David Donoghue threw an egg out of a helicopter onto a golf course in the UK, from a height of 213 meters (700 feet). He now has the record for the longest egg drop without breaking in the world (all without an outside structure for added protection!).

You can relate the activity to the challenge NASA scientists had in building a lander for the Mars Exploration Rover. Physically, it had to withstand both the heat of entry into the Martian atmosphere and the impact of landing. Strategically, they also had to figure out a way that the rover could right itself no matter how it landed. Students love to see how the structure they've built often resembles the one conceived by NASA scientists.

Objectives

  • Demonstrate curiosity and show inventiveness.
    Brainstorm in a team to generate ideas.
    Use problem-solving strategies in building simple structures.

Materials

  • large plastic sheet/tarp/vinyl tablecloth
    ladder (optional)

    Per team of 2–3 students:

    1 extra-large egg
    1 bag of materials (may include cardboard cup, string, tape, balloons, straws, etc.)
    2 sheets of scrap paper and 2 pencils

Key Questions

  • What was successful/unsuccessful in your design? What makes an egg a good ‘subject’ for the drop experiments?

What To Do

Preparation:

  1. Scout out accessible locations around the school for the egg drop at different heights. 
  2. Make enough bags of materials for student groups.

Exploration:

  1. Challenge the students (in teams of 2–3) to build a structure in 40 minutes that will prevent an egg from breaking when dropped from a high place. Brainstorm ways to increase the likelihood of safely landing their eggs.
  2. Each group gets a bag of materials, 2 pencils, and 2 sheets of scrap paper.
  3. The students cannot assemble anything for the first 10 minutes. This time is to be used to brainstorm and to draw a mockup of their structure on the scrap paper provided.
  4. When the 10 minutes is up, circulate around the class to ensure that the students have thoughtfully mocked up their landers. 
  5. Place the eggs in individual egg holders and hand out to the teams. Remind students that they cannot use the egg holder as part of their design.
  6. Drop the eggs from a launch point into the drop zone, which is protected by a plastic sheet, ensuring that each lander is dropped from the same distance. 
  7. Once dropped, the students check out the egg to see if it has broken or if there are any cracks. 
  8. The team whose egg survives the highest drop wins.

Teacher tips 

  • The teacher should be the one to launch the eggs to ensure fairness and to reduce the risk of injury (if dropping from a high distance).
  • Many of the supplies in this activity can be collected and reused!

Extensions

  • How would you modify your design to make it better? Present your revised mockup to the class. Assign prices to each craft item and give students a budget. Students come to the “store” with their designs and the teacher hands out the materials they’ve requested. Show the students the Mars Exploration Rover landing video.

Other Resources

Science World Resources | Full Lesson & other activities | Eggstraordinary Eggsperiments