Invisible Ink

INTRODUCTION

Invisible ink is an important part in many spy books and movies and many children are fascinated by it. In this experiment, invisible ink will be made and a solution will be made to show what was written with the invisible ink. The ink is made by mixing water and baking soda. The solution that can make the ink visible is a mixture of turmeric and rubbing alcohol. The turmeric solution is able to make the ink visible because it is a pH indicator. Turmeric has the ability to change color when reacting with baking soda, a base, to show the invisible ink message.

This is experiment should be done in a lab with adult supervision or, if doing it at home, in a kitchen with adult supervision.

GENERAL WARNINGS, CAUTIONS AND DANGERS

  • This experiment will stain, wear eye protection, gloves and an apron (or old clothes).
  • Do not eat, this experiment is not edible.

EQUIPMENT

  • Measuring Glass
  • Medium Sized Glass Bowl
  • Measuring Spoons ( 1 Tablespoon and 1 Teaspoon)
  • Glass Rod/ Spoon
  • 2 Paintbrushes/ Q-Tips
  • Plain White Blank Copy Paper

SUPPLIES

  • Water
  • Baking Soda
  • Rubbing Alcohol
  • Turmeric

PROCEDURE

Making the Invisible Ink:

  1. Fill a measuring cup with ½ cup of water.
  2. Add 1 tablespoon of baking soda to the measuring cup.
  3. Stir the baking soda into the water with a stir rod or a spoon.

Writing the Message:

  1. Use a paintbrush or a q-tips to draw a picture or write a message with the invisible ink on plain white copy paper.
  2. Wait 15 minutes for the paper to dry.

Color Changing Solution:

  1. While waiting for the paper to dry, add ½ cup of rubbing alcohol to a medium sized bowl.
  2. Add 1 teaspoon of turmeric to the rubbing alcohol.
  3. Stir the turmeric and rubbing alcohol with a clean stir rod or spoon.
  • The solution can stain. Glassware is recommended for this step for easy clean up.

Using the Solution:

  1. After the 15 minutes are up, use a clean paintbrush to apply the solution (made in the steps above) to the dry paper from step 5. The end result should exposed the message in a dark orange color.
  • Make sure gloves are on during this steps, solution can stain.

Disposal:

  1. All solid waste can be thrown in the trash and all liquid waste can go down the drain with water.

 

Helpful Videos:

 

 

Source:

Michelle. “Color-Changing Invisible Ink Activity.” ResearchParent.Com, 14 June 2023, researchparent.com/color-changing-invisible-ink/.

Cole, By: Neva. “Science Magic: Invisible Ink!: Blog.” Children’s Museum of New Hampshire (En-US), childrens-museum.org/blog/2020/04/science-magic-invisible-ink. Accessed 11 May 2024.