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Forwards and Backwards

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    Oregon Museum of Science and Industry

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Forwards and Backwards

In this activity, learners explore acids and bases by preparing six solutions that combine vinegar and ammonia, ranging from acid (all vinegar) to base (all ammonia). They add an indicator to each solution and compare the resulting colors to those on a pH scale chart. Learners then add drops of ammonia and vinegar to water and indicator, experimenting with the number of drops it takes to change the color of the water. This activity is currently used in the Chemical Reactions Unit in OMSI's Chemistry Lab. Cost estimates are per 100 learners.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
Under 5 minutes

Estimated Materials Cost:
$5 - $10 per group of students

Age Range:
Ages 8 - adult

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)


  • Physical Sciences
    • Chemistry
      • Chemical Reactions
      • Acids and Bases
      • Solutions
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations


To use this activity, learners need to:

  • see
  • see color
  • read
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



  • All Rights Reserved, Oregon Museum of Science and Industry, ©1997

Funding Source:

  • National Science Foundation, 9355628


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