National Informal STEM Education Network: Why are Seashells so Strong?

In this Short Activity, learners explore seashells and various structural models to discover that seashells are a composite material made of both inorganic and organic materials.

In this hands-on activity, visitors explore the structure of seashells and learn that seashells are a composite material made of both inorganic and organic materials. Visitors compare the mechanical properties of plaster bricks and dried sheets of glue, which helps them discover that both toughness and hardness are important mechanical properties. To see what a shell would be like if it were not so tough, visitors try to break normal shells and shells that have been either baked or soaked in bleach.


Shells have great mechanical properties, including high hardness and high toughness. Shells’ great mechanical properties are due to both their nanoscale structure and their combination of inorganic and organic materials.


  • That an object’s materials and structure determine its strength
  • That a composite material is a mixture of two or more materials
  • The difference between toughness and hardness
  • The differences in mechanical properties between dried glue sheets and plaster bricks
  • That bleach can remove organic material and baking can harm/degrade organic material


Nanometer-sized things are very small, and often behave differently than larger things do.

Scientists and engineers have formed the interdisciplinary field of nanotechnology by investigating properties and manipulating matter at the nanoscale.


Science Topics
Biology, Chemistry
Engineering Topics
K-6, Middle School, Educator
2nd Grade, 3rd Grade, 4th Grade, 5th Grade, 6th Grade, 7th Grade, 8th Grade
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