Sidewalk Chalk

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In this chemistry activity, learners witness an exothermic reaction, while making their very own, completely usable sidewalk chalk. This is also an excellent activity for exploring color mixing. In the "Now, Explore!" section, there are ideas for taking the activity one step further and experimenting with different amounts of water and plaster of Paris in order to see the effect on the final product.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
30 to 45 minutes

Estimated Materials Cost:
1 cent - $1 per student

Age Range:
Ages 8 - 14

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per student)

  • Plaster of Paris (available in the hardware or craft sections of most department stores)
  • Small paper cups (3.5 or 4 oz)
  • Measuring spoons
  • Plastic spoons
  • Liquid food coloring
  • Water
  • Newspapers


  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
      • Heat Transfer
    • Chemistry
      • Chemical Reactions
    • States of Matter
      • Changes of Phase
  • The Nature of Science
    • The Scientific Process
      • Asking Questions
      • Conducting Investigations

Informal Categories

  • Toys


To use this activity, learners need to:

  • see
  • see color
  • touch

Learning styles supported:

  • Links STEM to other topics of interest such as arts and humanities
  • Involves hands-on or lab activities


Includes alignment to state and/or national standards:

This resource is part of:

Access Rights:

  • Free access



  • All rights reserved, COSI Columbus, 2009