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In two separate bags, learners mix water with Epsom salts and detergent. They discover that one mixture becomes cold (dissolving is an endothermic process), and one becomes hot (dissolving is an exothermic process). Learners can then try different powders or different amounts of powders to compare results. This activity also gives ample opportunity for group observations and discussion about what characterizes a chemical reaction. Extensions are listed on page 9 of the activity guide. This activity is part of the 21-activity guide published by OMSI, No Hassle Messy Science with a Wow. All activities in this guide use household materials and all lesson plans include preparation directions, demonstrations, procedure sheets, cross-curricular connections, and scientific explanation of content.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 6 - 14

Resource Types:
Activity, Experiment/Lab Activity, Lesson/Lesson Plan

English, Spanish

Materials List (per group of students)

  • sealing plastic bags (Ziploc™) 2 per group
  • small plastic cups 2 per group
  • permanent markers (e.g. Sharpie™) 1 per group
  • spoon (e.g., teaspoon size) 2 per group
  • pop-top squeeze bottles1 per group
  • Epsom salts ¼ cup per group
  • detergent (with sodium carbonate)¼ cup per group
  • water 1 cup per group


  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
      • Heat Transfer
    • Energy
    • Chemistry
      • Chemical Reactions
      • Solutions
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Formulating Explanations


To use this activity, learners need to:

  • see
  • read
  • touch

Learning styles supported:

  • Involves teamwork and communication skills
  • Involves hands-on or lab activities


Foreign language versions of this resource:

Components that are part of this resource:

Includes alignment to state and/or national standards:

Access Rights:

  • Free access


  • Oregon Museum of Science and Industry


  • All rights reserved, Oregon Museum of Science and Industry, 2007

Funding Sources:

  • National Science Foundation
  • Camille and Henry Dreyfus Foundation