demonstrations:uncrushable_egg

Uncrushable Egg

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★★☆ Some safety precautions required to perform safely

Categories: Materials, Force

Alternative titles: Impossible Egg Crush

Summary

In this demonstration, participants attempt to crush an egg by squeezing it in their hand. Despite applying strong force, the egg does not break when the pressure is evenly distributed. However, uneven pressure, such as pressing on one side or squeezing with a ring on, causes the egg to crack.

Procedure

  1. Place a raw egg in the palm of your hand.
  2. Wrap your fingers completely around the egg.
  3. Hold the egg over a sink or bowl and squeeze by applying even pressure all around. Notice that the egg does not break.
  4. Next, hold the egg between your thumb and forefinger and squeeze at the top and bottom. Observe the outcome.
  5. Place the egg in your palm again and press firmly on only one side of the shell without squeezing evenly. Record what happens.
  6. Try squeezing the egg again while wearing a ring on one finger of the squeezing hand. Compare the results to the previous trials.

Wonder Zone: Impossible Egg Crush - Cincinnati Museum Center:


Breaking An Egg With One Hand Experiment | Impossible Egg Crush Experiment | Egg Experiment For Kids - Playing With Rain:


📄 Impossible Egg Crush - Steve Spangler: https://stevespangler.com/experiments/impossible-egg-crush/

Variations

  • Compare fresh eggs with older eggs to see if the shell strength changes.
  • Try the experiment with boiled eggs to compare shell strength when the contents are solid.
  • Test different bird eggs (e.g., chicken, quail, duck) for strength differences.

Safety Precautions

  • Use a gardening glove to avoid potential cuts.
  • Perform the experiment over a sink, bowl, or plate to catch spills.
  • Wash hands thoroughly after handling raw eggs to prevent salmonella risk.
  • Avoid eating eggs that have cracked during the demonstration.
  • Use adult supervision if young children are conducting the experiment.

Questions to Consider

  • Why does the egg resist breaking when squeezed evenly? (The curved shell distributes the pressure evenly, acting like an arch.)
  • Why does the egg crack when pressed on one side? (Uneven force concentrates stress at one point, breaking the shell.)
  • How does this relate to how hens sit on their eggs without breaking them? (The hen’s weight is spread evenly, but a chick pecks at one spot with uneven force.)
  • What does this experiment show about the strength of natural structures? (It demonstrates how nature uses shapes like arches for strength and efficiency.)