Invisible Ink Demonstration

Add to list Go to activity
Activity link broken? See if it's at the internet archive
In this chemistry demonstration, learners will discover that phenolphthalein is a chemical that displays different colors depending on the acidity or basicity of the environment. Learners will be surprised to see a "secret message" appear in bright pink ink when it is sprayed with Windex containing ammonia (a base). They compare this to what happens when the message is sprayed with Windex containing acetic acid (nothing!).

Quick Guide

Preparation Time:
5 to 10 minutes
Learning Time:
Under 5 minutes
Estimated Materials Cost:
$5 - $10 per group of students
Age Range:
Ages 6 - 18
Resource Types:
Activity, Demonstration, Experiment/Lab Activity
Language:
English

Materials List (per group of students)

  • phenolphthalein solution
  • cotton swab or artist's paint brush
  • white typing paper or paper towel, roll
  • 100 mL beaker, glass or plastic cup
  • ammonia or Windex spray with ammonia
  • acetic acid or vinegar

Keywords

Subjects

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

Informal Categories

  • Crime Science

Audience

To use this activity, learners need to:

  • see
  • see color

Learning styles supported:

  • Involves hands-on or lab activities

Other

This resource is part of:

Access Rights:

  • Free access with registration

By:

Rights: