The China Hammer Mystery

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In this activity, learners are asked to examine the differences between two materials in a pair. Learners deduce which material was “original” and which has been altered, and propose an application for the “altered” material. Through this activity, learners compare their lab experience to “real world” knowledge and get a chance to be creative and propose new inventions. Safety note: The major hazard in this lab is burns from liquid nitrogen or hot water. [Activity is publicly available through a web crawler capture on]

Quick Guide

Preparation Time:
5 to 10 minutes

Learning Time:
45 to 60 minutes

Estimated Materials Cost:
$10 - $20 per group of students

Age Range:
Ages 11 - 18

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • Rubber ball with glass transition temperature well below room temperature
  • Rubber ball with glass transition temperature near room temperature
  • Shape memory alloy spring
  • Normal metal spring
  • Microscope slide
  • Microscope slide with hydrophobic coating
  • Superabsorbent granules from diapers
  • Table salt
  • Tap water
  • Hot plate
  • Beakers
  • Plastic baggies
  • Dewar of liquid nitrogen
  • Insulated container
  • Tongs
  • Superballs
  • Small cups
  • Eye droppers
  • Paper towels
  • Microscope
  • Paper
  • Pens/pencils


  • Engineering and Technology
    • Engineering
      • Metallurgy and Materials Engineering
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
    • Chemistry
      • Chemical Reactions
      • Solutions
    • States of Matter
      • Solids


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities

Culture, ethnicity, and gender

  • Girls

    • Explicity developed for this group


Components that are part of this resource:

Access Rights:

  • Free access


  • Hackett, Emily


Funding Sources:

  • NSF Grant DMR, 1120296
  • NSF Grant DMR, 0079992