Jem's Pykrete Challenge

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In this activity, learners make pykrete by freezing a mixture of water and a material like cotton wool, grass, hair, shredded paper, wood chips, or sawdust. Learners discover that pykrete has some interesting properties, since compared to normal ice it melts slowly and is much stronger and tougher. Use this activity to talk about the advantages and disadvantages of different types of materials. Notes: Since pykrete will melt, testing should be done outdoors. Video is not available in the US, but it is not needed to understand how to do the activity.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
4 to 24 hours

Estimated Materials Cost:
1 cent - $1 per student

Age Range:
Ages 4 - adult

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per student)

  • A long narrow box (an empty plastic wrap or foil box is suggested, but feel free to experiment)
  • Water
  • Your special 'pykrete' material, such as cotton wool, grass, hair, shredded paper, wood chips, or sawdust
  • A set of bathroom scales


  • Earth and Space Science
    • Earth Structure
      • Oceans and Water
  • Engineering and Technology
    • Engineering
      • Mechanical Engineering
      • Metallurgy and Materials Engineering
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
    • Chemistry
      • Chemical Bonding
    • States of Matter
      • Solids
    • Structure and Properties of Matter
      • Atomic Structure

Informal Categories

  • Outdoor Activity


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



  • All rights reserved, BBC, 2012