Incubation and Embryology - University of Illinois

Can You Crack Them?


Science, Language Arts


6 and up


Students will test the strength of the arch in eggs.


  • 4 raw eggs
  • modeling clay
  • a 12" x 18" board
  • bathroom scale
  • books to be used as weights
  • small garbage sack


  1. Soften eight pieces of modeling clay. Each should make a two-inch cube. Roll the clay into balls and flatten them slightly. The shape should look like a thick, round disk.
  2. Make a slight indentation in the top of each piece of clay so that it becomes a cushion for the egg. Place one on the top and bottom of each egg.
  3. Place the eggs on a garbage sack that is laying unopened on the ground as a drop cloth.
  4. Position the eggs so that they will support each corner of the board.
  5. Place the board on the eggs, checking to make sure all four eggs support the board evenly.
  6. Place books on the board, one at a time, being careful to keep them balanced in the middle of the board.
  7. Continue to do so until the eggs break. Usually, one side will give way first, so be ready to catch the books.
  8. Weigh the books to determine the weight that broke the eggs. Divide the number of pounds by the number of eggs and you will have the average weight each egg held until one broke.


Is there a better way to measure how much weight an egg can hold without breaking?

If only one egg broke, does that mean the other eggs could hold more weight? How could this be tested?

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