Secret Goldenrod Messages

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In this activity, learners write invisible messages on goldenrod paper, and make the message appear and disappear using acids and bases. Goldenrod paper is paper that has been dyed with natural goldenrod pigment. The pigment is a natural indicator that changes from gold to red when exposed to bases (such as laundry detergent, baking soda), and back to gold when exposed to an acid (such as vinegar). The secret message is written with wax, which protects the surface of the paper from the applied solutions.

Quick Guide

Preparation Time:
5 to 10 minutes
Learning Time:
30 to 45 minutes
Estimated Materials Cost:
1 cent - $1 per student
Age Range:
Ages 6 - 14
Resource Type:
Activity
Language:
English, Spanish

Materials List (per student)

  • Measuring spoons
  • Powdered laundry detergent
  • 4 Plastic cups
  • Pencil or pen
  • Masking tape
  • Baking soda
  • Water
  • Vinegar
  • Goldenrod paper
  • Piece of white candle or crayon
  • Cotton swabs or paintbrushes

Keywords

Subjects

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

Informal Categories

  • Crime Science

Audience

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

Other

Access Rights:

  • Free access

By:

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